U.S. patent application number 11/898410 was filed with the patent office on 2008-03-27 for process for production of molecular devices.
This patent application is currently assigned to NATIONAL INSTITUTE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY. Invention is credited to Seiichi Furumi, Shinro Mashiko, Akira Otomo.
Application Number | 20080076887 11/898410 |
Document ID | / |
Family ID | 28677556 |
Filed Date | 2008-03-27 |
United States Patent
Application |
20080076887 |
Kind Code |
A1 |
Furumi; Seiichi ; et
al. |
March 27, 2008 |
Process for production of molecular devices
Abstract
An object of the present invention is to provide a method of
effectively producing a nano-particle and a nano-wire, and others.
Specifically, the present invention provides a method of producing
a molecular device including: the use of a molecular structure
having a higher atomic density in the periphery than in the
interior and bonding residues in the periphery; and a step of
crosslinking the bonding residues, and the method of producing a
molecular device according to claim 1, characterized in that the
molecular structure is constituted by a skeleton portion having a
skeleton structure, and a terminal portion which is arranged in the
outer shell of the skeleton portion, has a higher atomic density
than that of the skeleton portion and has bonding residues; and
that in the step of crosslinking the bonding residues, the bonding
residues in the terminal portion of the molecular structure are
crosslinked to form the molecular structure into a shell structure,
and others.
Inventors: |
Furumi; Seiichi; (Tokyo,
JP) ; Otomo; Akira; (Tokyo, JP) ; Mashiko;
Shinro; (Tokyo, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
NATIONAL INSTITUTE OF INFORMATION
AND COMMUNICATIONS TECHNOLOGY
Tokyo
JP
|
Family ID: |
28677556 |
Appl. No.: |
11/898410 |
Filed: |
September 12, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10509380 |
Sep 27, 2004 |
7285604 |
|
|
PCT/JP03/03669 |
Mar 26, 2003 |
|
|
|
11898410 |
Sep 12, 2007 |
|
|
|
Current U.S.
Class: |
525/540 |
Current CPC
Class: |
C08G 73/0672 20130101;
C08G 73/02 20130101; B82Y 30/00 20130101; C08F 291/00 20130101;
C08G 73/0206 20130101; C08G 83/003 20130101; C07C 233/40
20130101 |
Class at
Publication: |
525/540 |
International
Class: |
C08G 73/02 20060101
C08G073/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2002 |
JP |
2002-91548 |
Mar 29, 2002 |
JP |
2002-94211 |
Claims
1. A method of producing a molecular device including: the step of
obtaining a molecular structure having a shell structure by joining
the bonding residues of the molecular structure, wherein using a
molecular structure having a plurality of bonding residues in the
molecule, and a sensitizer, and imparting energy to the
sensitizer.
2. A method of producing a molecular device including: a step of
obtaining the molecular structure having a shell structure, using a
molecular structure having a higher atomic density in the periphery
than in the interior and having bonding residues in the periphery,
and a photo sensitizer molecule that is included inside the
molecular structure, or is covalently bonded, ionically bonded,
coordinately bonded, metallically bonded or hydrogen bonded with
the molecular structure; and joining the bonding residues by photo
irradiation to.
3. The method of producing a molecular device according to claim 2,
characterized in that the molecular structure is constituted by a
skeleton portion having a skeleton structure and a terminal portion
which is arranged in the outer shell of the skeleton portion, has a
higher atomic density than that of the skeleton portion, and has a
plurality of bonding residues; and that in the shell-forming step,
the bonding residues in the terminal portion of the molecular
structure are joined by irradiating the photo sensitizer molecule
with light.
4. The method of producing a molecular device according to claim 2,
characterized in that the plurality of bonding residues present in
the terminal portion are joined to obtain the molecular structure
having the shell structure.
5. The method of producing a molecular device according to claim 2,
characterized in that the method further includes the use of
molecules of a crosslinking agent, makes the molecules of the
crosslinking agent crosslink with the bonding residues, and a
plurality of molecular structures three-dimensionally joined
through the crosslinkable molecule.
6. The method of producing a molecular device according to any one
of claims 3 to 5, wherein the bonding residue is an optically
bonding residue.
7. The method of producing a molecular device according to any one
of claims 3 to 5, wherein the bonding residue has at least one of
double bonds and/or triple bonds.
8. The method of producing a molecular device according to any one
of claims 3 to 5, wherein the bonding residue is any one of a
cinnamic acid group, an .alpha.-cyano cinnamic acid group, a
coumarin group, a chalcone group, a cinnamylidene acetate, group, a
p-phenylene diacrylate group, an acetylene group, a diacetylene
group, a diphenyl acetylene group and an anthracene group.
Description
[0001] This application is a divisional of Ser. No. 10/509,380,
filed Sep. 27, 2004, which is a National Stage Application Under 35
U.S.C. .sctn. 371 of PCT/JP03/03669, filed on Mar. 26, 2003 which
is based upon and claims the benefit of priority from prior
Japanese Patent Application No. 2002-91548, filed on Mar. 28, 2002
and Japanese Patent Application No. 2002-94211, filed Mar. 29,
2002, the entire contents of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention relates to a method of producing a
molecular aggregate of which the linked form is controlled in a
molecular level, by irradiating a molecular structure having a
bonding residue in the periphery with light, and through taking
advantage of the photochemical process and the photophysical
process, selectively and effectively combining the periphery of the
molecule or mutual molecular structures. By applying the present
technique, it becomes easy to make various three-dimensional
molecular devices of highly dense molecules.
BACKGROUND ART
[0003] The present silicon semiconductor element has remarkably
improved the ability of computers by its hyperfine structure and
integrated structure into high density. In the silicon
semiconductor elements, an n-type or p-type semiconductor is made
by doping a very small amount of impurities into silicon. However,
by a progress of hyperfine processing, the number of impurity atoms
contained in one element has been extremely decreased, and as a
result, the element cannot work as a semiconductor any longer in
principle. The dimension of the element considered to be the limit
is a plurality of tens of nm, and if a hyperfine processing
technology be the limit is a plurality of tens of nm, and if a
hyperfine processing technology advances at a current pace, it is
predicted that the limit will be reached after a plurality of tens
of years.
[0004] In a fine processing technology by optical lithography using
a chemical amplification type photo resist, the applied light has
been shifted from visible light to ultraviolet light or deep
ultraviolet light, but the limit of resolution is considered to be
about 70 nm. Recently, an application of lithography using an
X-ray, a focused ion beam and an electron beam, which have shorter
radiation wavelengths has been investigated. However, in order to
use these radiation wavelengths, the development of a new photo
resist, an electron beam resist, an optical system and a mask, and
the reduction of a manufacturing cost are necessary and expected.
However, the technical and practical problems have not been
improved yet at this stage. Accordingly, the technology based on a
top-down concept reaches a limit.
[0005] As for a technology based on a bottom-up concept, a
technique using a scanning probe microscope captures attention at
present. One of the technologies can make a nanometric structure by
disposing and reacting atoms or molecules in an arbitrary place
with the use of a scanning tunneling microscope (STM). The study is
described, for instance, in a scientific magazine, Nature, 409, 683
(2001) by Y. Okawa and M. Aono. Another technology has succeeded in
the production of a self-organization film which is patterned in a
nanometric order, by drawing the pattern on a substrate with a
solution of thiol molecules coated on the top of a fine needle in
an atomic force microscope (AFM). The study is described, for
instance, in a scientific magazine, Science, 283, 661 (1999) by R.
D. Piner, J. Zhu, F. Xu, S. Hong and C. A. Mirkin. Both
technologies are excellent techniques for making a two-dimensional
structure in a nanometric region, but are difficult to construct a
three-dimensional structure, and are not practical from the
viewpoint of a manufacturing cost.
[0006] The above-described methods for making a device are based on
the concept of the so-called top-down technology, and have
difficulty in producing a three-dimensional molecular device having
a smaller size.
[0007] At present, a new molecular device of highly dense
molecules, which can be operated even though having a dimension of
a nanometric level, is energetically developed in a worldwide
scale. For instance, a single electron element capable of
controlling the switching on and off with one electron, and a
molecular device using a functional organic molecule as a molecular
structure are proposed. In order to put the molecular devices based
on new concepts to practical use, many problems must be still
solved. One big problem among them is how to selectively combine
individual molecules. This is the big problem of the bottom-up
technique, and is mentioned in Nikkei Science of a scientific
magazine, 2001, December, page 37. However, an effective method for
controlling the coupling of individual molecular elements has not
been found until now.
DISCLOSURE OF THE INVENTION
[0008] As a result of intensive research for the purpose of solving
the above described problems, the present inventors have found that
each molecular structure necessary in making a molecular device of
highly dense molecules, can be combined by photoirradiation or the
like. At least one problem out of the above described problems is
solved by the invention described below.
[0009] (1) The first invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a higher atomic density in the
periphery than in the interior and bonding residues in the
periphery; and a step of crosslinking the bonding residues". For
instance, a dendrimer has a higher atomic density in the periphery
(the branch part) than in the interior (so-called the core part).
In the present invention, a molecular device is produced by thus
using a molecular structure having bonding residues in the
periphery (the outside region) among molecular structures having
more atoms in the outside region of a molecule than in the vicinity
of the center of the molecule, and crosslinking (including
combining) the above described bonding residues. By crosslinking
the bonding residues in a molecular structure, nano-particles and
nano-wires can be produced, and by using these, a molecular device
having functional molecular structures and functional molecular
aggregates assembled at a high density, can be produced.
[0010] (2) Another invention according to the present application
is "the method of producing a molecular device according to the
item (1), characterized in that the molecular structure is
constituted by a skeleton portion having a skeleton structure, and
a terminal portion which is arranged in the outer shell of the
skeleton portion, has a higher atomic density than that of the
skeleton portion and has bonding residues; and that in the step of
crosslinking the bonding residues, the bonding residues in the
terminal portion of the molecular structure are crosslinked to form
a shell structure in the molecular structure". The molecular
structure thus acquiring the shell structure is also called a
nano-particle. The nano-particle has a space in a shell, and can
include various materials.
[0011] (3) Another invention according to the present application
is "the method of producing a molecular device according to the
item (1) or (2), wherein the bonding residue is an optically
bonding residue". Because the bonding residue is the optically
bonding residue, the reaction can be controlled by
photoirradiation.
[0012] (4) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the item (1), (2) or (3), wherein the bonding residue has at
least one of one or both of a double bond and a triple bond".
[0013] (5) Another invention according to the present application
is "the method of producing a molecular device according to the
item (1) or (2), wherein the bonding residue is any one of a
cinnamic acid group, an .alpha.-cyano cinnamic acid group, a
coumalin group, a chalcone group, a cinnamylidene acetate group, a
p-phenylene diacrylate group, an acetylene group, a diacetylene
group, a diphenyl acetylene group and an anthracene group". These
groups are effectively coupled, and are effective for crosslinking
such as intramolecular coupling and intermolecular coupling.
(6) Another invention according to the present application is "the
method of producing a molecular device according to any one of the
items (1) to (5), wherein the molecular structure is a
dendrimer".
[0014] (7) Another invention according to the present application
is "the method of producing a molecular device according to the
item (6), wherein the dendrimer is expressed by the following
formula (I) or (II)": ##STR1## wherein n represents an integer of
10 or less, and ##STR2## wherein n represents an integer of 10 or
less and R represents a linkage group.
[0015] Here, in the general formulas (I) and (II), n is an integer
of 1 to 10, preferably of 2 to 10, and further preferably of 3 to
8. In addition, R (a coupling group) in the general formula (2)
includes, for instance, an alkenyl group with C.sub.1 to C.sub.10
and an alkynyl group with C.sub.2 to C.sub.10, but is not
particularly limited so far as being a coupling group used for the
dendrimer.
(8) Another invention according to the present application is "the
method of producing a molecular device according to the item (7),
wherein R in the general formula (II) is an alkenyl group with
C.sub.1 to C.sub.10 or an alkynyl group with C.sub.2 to
C.sub.10".
(9) Another invention according to the present application is "the
method of producing a molecular device according to the item (7) or
(8), wherein each n in the general formulas (I) and (II) is an
integer of 2 to 10".
[0016] (10) Another invention according to the present application
is "a molecular structure (a nano-particle) having a shell
structure made by crosslinking the bonding residues of the
molecular structure which has a higher atomic density in the
periphery than in the interior and has the bonding residues in the
periphery, into a shell".
(11) Another invention according to the present application is "a
molecular device including the molecular structure having the shell
structure according to the item (10)".
[0017] (12) Another invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a plurality of bonding residues in the
molecule, and a sensitizer; and the step of joining the bonding
residues of the molecular structure by an energy imparting step of
imparting energy to the sensitizer, to obtain the molecular
structure having a shell structure". The energy imparted to the
sensitizer propagates to the molecular structure. The energy having
propagated to the molecular structure is used for joining the
bonding residues. Here, "plurality" for the number of bonding
residues means 2 or greater, and though varying with the structure
of the molecular structure, the number of bonding residues is
normally 4 or greater but 1,000 or less, preferably 8 or greater
but 512 or less, and further preferably 16 or greater but 255 or
less (hereafter, the same). The molecular structure obtained in
such a step includes a functional nano-particle having a shell
structure, and a molecular device comprising the functional
nano-particles has various functions according to the properties of
the various nano-particles.
[0018] (13) Another invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a plurality of bonding residues in the
molecule, and a sensitizer; an energy imparting step of imparting
energy to the sensitizer; one or both stages of an energy transfer
process of transferring the energy to the bonding residues from the
energy-imparted sensitizer, and an electron-imparting process of
transferring electrons to the bonding residues from the
energy-imparted sensitizer; and a step of obtaining the molecular
structure having a shell structure by using the energy transfer
process or the electron-imparting process as a driving force for
the chemical bonding reaction of the bonding residues". The
molecular structure obtained in such steps includes a functional
nano-particle having the shell structure, and a molecular device
comprising the functional nano-particles has various functions
according to the properties of the various nano-particles.
[0019] (14) Another invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a plurality of bonding residues in the
molecule, a sensitizer and a crosslinking agent containing a
plurality of bonding residues; and the step of crosslinking the
bonding residues in the molecule of the molecular structure with
the crosslinking agent by using an energy imparting step of
imparting energy to the sensitizer, to obtain a molecular aggregate
which three-dimensionally combines a plurality of molecular
structures". The molecular assembly obtained through such a step
includes a nano-wire. One example of the nano-wire includes one
having the molecular structures regularly disposed. Each molecular
structure functions as a molecular device having various functions
such as an optical memory effect. In addition, a molecular
aggregate (or a molecular device) having various functions can be
produced by combining the molecular structures one-dimensionally,
two-dimensionally and three-dimensionally one after another into a
linear shape, a grid shape or a radical shape. The position where
the molecular structure is combined, can be controlled by
controlling the position of the bonding residue in the molecular
structure, which leads to a control of the growing direction in the
molecular aggregate formed by a sequential coupling of the
molecular structure and the extension. In addition, spacings among
the molecular structures constituting the molecular aggregate, can
be controlled by controlling the length of a crosslinking agent.
Here, the number of bonding residues existing inside the
crosslinking agent is not particularly limited so far as being 2 or
more, but is preferably 2 or more but 10 or less, and further
preferably 2 or more but 4 or less (hereafter, the same). In
addition, if the crosslinking agent of a medium shows a liquid
crystal property, it is possible to impart directionality to a
nano-wire by applying an external field such as an electric field
and a magnetic field.
[0020] (15) Another invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a plurality of bonding residues in the
molecule, a sensitizer, and a crosslinking agent containing a
plurality of bonding residues; the energy imparting step of
imparting energy to the sensitizer; one or both of an energy
transfer process and an electron transfer process, which are stages
including energy transfer or electron transfer from the
energy-imparted sensitizer to one or both of the bonding residues
of the structure and the bonding residues of the crosslinking
agent; and the step of crosslinking the bonding residues in the
molecule of the molecular structure with the crosslinking agent by
the energy transfer process or the electron-imparting stage, to
obtain a molecular aggregate having a plurality of molecular
structures three-dimensionally combined through the crosslinking
agent". The molecular aggregate obtained through such steps
includes a nano-wire, for instance. One example of the nano-wire
includes one having the molecular structures regularly
disposed.
[0021] (16) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (12) to (15), wherein the energy imparted to the
sensitizer in the energy imparting step is an energy originating in
any one of an electron, an ion and an electromagnetic wave, or a
combination thereof".
[0022] (17) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (12) to (15), wherein the energy imparted to the
sensitizer in the energy imparting step is a light energy due to an
ultra-violet ray, a visible ray and an infrared ray".
[0023] (18) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (12) to (15), characterized in that the energy
imparted to the sensitizer in the energy imparting step is a light
energy due to an ultra-violet ray, a visible ray and an infrared
ray; and that the energy transfers from the energy-imparted
sensitizer to the bonding residues through an energy transfer
process".
[0024] (19) Another invention according to the present application
is "The method of producing a molecular device according to the
item (18), wherein the energy imparted to the sensitizer in the
energy imparting step is a light energy due to an ultra-violet ray,
a visible ray and an infrared ray, and the energy transfer in the
energy transfer process is a triplet energy transfer process".
(20) Another invention according to the present application is "the
method of producing a molecular device according to any one of the
items (12) to (19), wherein the bonding residue is an optically
bonding residue".
[0025] (21) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (12) to (19), wherein the bonding residue has at least
one of one or both of a double bond and a triple bond".
[0026] (22) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (12) to (19), wherein the bonding residue is one of a
cinnamic acid group, an .alpha.-cyano cinnamic acid group, a
coumarin group, a chalcone group, a cinnamylidene acetate group, a
p-phenylene diacrylate group, an acetylene group, a diacetylene
group, a diphenyl acetylene group and an anthracene group".
[0027] (23) Another invention according to the present application
is "a method of producing a molecular device including: the use of
a molecular structure having a higher atomic density in the
periphery than in the interior and having bonding residues in the
periphery, and a photosensitizer molecule that is included inside
the molecular structure, or is covalently bonded, ionically bonded,
coordinately bonded, metallically bonded or hydrogen bonded with
the molecular structure; and a shell-forming step of joining the
bonding residues by photoirradiation, to obtain the molecular
structure having the shell structure".
[0028] (24) Another invention according to the present application
is "the method of producing a molecular device according to the
item (23), characterized in that the molecular structure is
constituted by a skeleton portion having a skeleton structure and a
terminal portion which is arranged in the outer shell of the
skeleton portion, has a higher atomic density than that of the
skeleton portion, and has a plurality of bonding residues; and that
in the shell-forming step, the bonding residues in the terminal
portion of the molecular structure are combined by irradiating the
photosensitizer molecule with light".
[0029] (25) Another invention according to the present application
is "the method of producing a molecular device according to the
item (23), characterized in that the plurality of bonding residues
existing in the terminal portion are combined to obtain the
molecular structure having the shell structure".
[0030] (26) Another invention according to the present application
is "the method of producing a molecular device according to the
item (23), characterized in that the method further includes the
use of the molecule of a crosslinking agent, makes the molecule of
the crosslinking agent crosslink with the bonding residues, and
three-dimensionally combines a plurality of molecular structures
through the crosslinkable molecule".
(27) Another invention according to the present application is "the
method of producing a molecular device according to any one of the
items (23) to (26), wherein the bonding residue is an optically
bonding residue".
[0031] (28) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (23) to (26), wherein the bonding residue has at least
one of one or both of a double bond and a triple bond".
[0032] (29) Another invention according to the present application
is "the method of producing a molecular device according to any one
of the items (23) to (26), wherein the bonding residue is any one
of a cinnamic acid group, an .alpha.-cyano cinnamic acid group, a
coumarin group, a chalcone group, a cinnamylidene acetate group, a
p-phenylene diacrylate group, an acetylene group, a diacetylene
group, a diphenyl acetylene group and an anthracene group".
(30) Another invention according to the present application is "the
method of producing a molecular device according to any one of the
items (12) to (29), wherein the molecular structure is a
dendrimer".
[0033] (31) Another invention according to the present application
is "the method of producing a molecular device according to the
item (30), wherein the dendrimer is expressed by the following
formula (I) or (II)": ##STR3## wherein n represents an integer of
10 or less, or ##STR4## wherein n represents an integer of 10 or
less and R represents a linkage group.
[0034] Here, in the general formulas (I) and (II), n is an integer
of 1 to 10, preferably of 2 to 10, and further preferably of 3 to
8. In addition, R (a coupling group) in the general formula (II)
includes, for instance, an alkenyl group with C.sub.1 to C.sub.10
and an alkynyl group with C.sub.2 to C.sub.10, but is not
particularly limited so far as being a coupling group used for the
dendrimer.
(32) Another invention according to the present application is "the
method of producing a molecular device according to the item (31),
wherein R in the general formula (II) is an alkenyl group with
C.sub.1 to C.sub.10 or an alkynyl group with C.sub.2 to
C.sub.10".
(33) Another invention according to the present application is "the
method of producing a molecular device according to the item (31)
or (32), wherein each n in the general formulas (I) and (II) is an
integer of 2 to 10".
[0035] (34) Another invention according to the present application
is "a molecular structure having a shell structure obtained by:
using a molecular structure constituted by a skeleton portion
having a skeleton structure, and a terminal portion which is
arranged in the outer shell of the skeleton portion, has a higher
atomic density than that of the skeleton portion and has a
plurality of bonding residues, and a photosensitizer molecule
included inside the molecular structure; and joining the bonding
residues in the terminal portion by taking advantage of the
spectral sensitization of the photosensitizer molecule irradiated
with light".
[0036] (35) Another invention according to the present application
is "a molecular aggregate obtained by: using a molecular structure
constituted by a skeleton portion having a skeleton structure, and
a terminal portion which is arranged in the outer shell of the
skeleton portion, has a higher atomic density than that of the
skeleton portion and has a plurality of bonding residues, a
photosensitizing molecule contained inside the molecular structure,
and the molecule of a crosslinking agent; and crosslinking the
bonding residues with the molecule of the crosslinking agent
through irradiating the photosensitizer molecule with light to
combine a plurality of molecular structures".
(36) Another invention according to the present application is "a
molecular device including the molecular structure having the shell
structure according to the item (34), or the molecular aggregate
according to the item (35)".
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1 is a conceptual diagram of a molecular structure (a
nano-particle) having a shell structure;
[0038] FIG. 2 is a conceptual diagram of a nano-particle according
to the present invention;
[0039] FIG. 3 is a conceptual diagram of a molecular aggregate (a
nano-wire);
[0040] FIG. 4 is a conceptual diagram of a nano-wire according to
the present invention;
[0041] FIG. 5 is a conceptual diagram of a photoconductive
nano-wire by a rod-shaped dendrimer;
[0042] FIG. 6 is a conceptual diagram showing one example of a
single electron transistor (SET);
[0043] FIG. 7 is a conceptual diagram showing one example of a
T-type optoelectronic device (TOED); and
[0044] FIG. 8 shows one example of a dendrimer.
BEST MODE FOR CARRYING OUT THE INVENTION
[0045] A method of producing a molecular structure, a molecular
aggregate and a molecular device according to the present invention
will be now described in detail below.
[0046] A method of producing a molecular device according to the
present invention uses a molecular structure which has a higher
atomic density in the periphery than in the interior and has a
bonding residue in the periphery. According to one example
according to the present invention, a molecular structure or a
molecular aggregate is produced by crosslinking the bonding residue
existing in the periphery of the molecular structure, within the
molecular structure or between the molecular structures.
[0047] In another example according to the present invention, an
energy is imparted to a solution or a solid containing a molecular
structure and a sensitizer through the light having wavelengths
absorbed by the above described sensitizer, or the like. The
solution or the solid may contain a binding resin (a binder) and
other secondary materials. In the present invention, a molecular
structure having a shell structure or a molecular aggregate having
the molecular structures three-dimensionally combined is produced
by using a phenomenon that light energy is absorbed in a
sensitizer; the energy absorbed by the sensitizer transmits to a
molecular structure such as a dendrimer; alternatively an electron,
an ion or a radical migrates; and the energy causes a bonding
reaction or a crosslinking reaction of the bonding residue existing
in the molecular structure.
[0048] Each molecular structure preferably functions as a molecular
element having various functions such as an optical memory effect.
Then, a molecular aggregate (or a molecular device) having various
functions can be produced by one-dimensionally, two-dimensionally
and three-dimensionally combining the molecular structures one
after another into a linear shape, a grid shape or a radical shape.
The position where the molecular structure is combined, can be
controlled by controlling the position of the bonding residue in
the molecular structure, which leads to a control of the growing
direction in the molecular aggregate formed by a sequential
coupling of the molecular structure and the extension. In addition,
spacings among the molecular structures composing the molecular
aggregate can be controlled by controlling the length of a
crosslinking agent.
[0049] Here, a molecular structure means a molecule in which a
plurality of parts having different functions exist in different
portions of one molecule such as a residue part and a central part.
The molecular structure includes the one constituted by a skeleton
portion having a skeleton structure, and a terminal portion which
is arranged in the outer shell (outside) of the skeleton portion,
has a higher atomic density than that of the skeleton portion, and
has bonding residues. The molecular structure preferably has a
plurality of (two or more) bonding residues. The bonding residue is
preferably an optically bonding residue. The molecular structure is
preferably a dendrimer. The dendrimer is preferably one shown in
the above described general formula (I) or in the above described
general formula (II). Here, n in the general formulas (I) and (II)
is an integer of 1 to 10, preferably of 2 to 10, and further
preferably of 3 to 8. In addition, R in the general formula (II)
includes an alkenyl group with C.sub.1 to C.sub.10 and an alkynyl
group with C.sub.2 to C.sub.10, but is not particularly limited so
far as being a coupling group used for the dendrimer.
[0050] The molecular structure is preferably a molecule which can
contain a sensitizer, or a molecule which is covalently bonded,
ionically bonded, coordinately bonded, metallically bonded or
hydrogen bonded with a sensitizer, and particularly preferably a
dendrimer (a hyper-branched polymer) having an optical
functionality and an electronic functionality, but is not limited
in particular so far as being a compound having a bonding residue.
The molecule of the dendrimer has a nanometric space in itself, and
has an uniqueness capable of including a foreign molecule or a
foreign atom in the space. Details on encapsulation phenomenon of
the dendrimer are described in Science, 266, 1226 (1994) by J.
Jansen, E. Berg and E. Meijer; and in Nature, 389 and 368 (1997),
by A. Cooper, J. Londono, G. Wignall, J. McClain, E. Samulski, J.
Lin, A. Dobrynin, M. Rubinstein, A. Burke, J. Frechet and J.
DeSimone; which are both scientific magazines.
[0051] A bonding residue (an photocrosslinkable residue) in a
molecular structure includes (a) an aliphatic residue having an
unsaturated double bond, such as a vinyl group, an acrylate group
and a methacrylate group, (b) an aromatic residue having an
unsaturated double bond, such as a cinnamic acid group, an
.alpha.-cyano cinnamic acid group, a coumarin group, a chalcone
group, a cinnamylidene acetate group, a p-phenylene diacrylate
group, a distyrylpyrazine group and an anthracene group, (c) an
aliphatic residue having an unsaturated triple bond, such as an
acetylene group and a diacetylene group, and (d) an aromatic
residue having an unsaturated triple bond, such as a
diphenyl-acetylene group, a phenyl azide group and a dypyridyl
diacetylene group. In addition, the derivative materials thereof
are also acceptable. The residues in (a) require a radical
photopolymerization initiator in order to show a radical
polymerization reaction. On the other hand, the photocrosslinkable
residues in (b) to (d) do not require such a photopolymerization
initiator as is required in the case of (a), because they show a
photoaddition reaction according to the Woodward-Hoffmann's law,
such as a [2.pi.-2.pi.] photodimerization reaction. Details on
these photosensitive residues are described in "Photosensitive
Polymer" of Kodansha scientific (1977), by Nagamatsu Mototaro and
Inui Hideo.
[0052] As for the irradiation light used when preparing a
crosslinked body by the light, an x-ray, an electron beam, an
ultra-violet ray, a visible ray or an infrared-ray (a heat ray) is
used. Among them, the ultraviolet ray or the visible ray is
particularly preferable. A usable light source includes an
extra-high pressure mercury lamp, a low pressure mercury lamp, a
xenon lamp, a mercury xenon lamp, a halogen lamp, a fluorescent
lamp, a gas laser, a liquid laser, and a solid state laser. In
addition, the surface plasmon radiation of the light emitted from
these light sources may be used.
[0053] In order to combine (crosslink) bonding residues mutually or
molecular structures each other, the bonding residue may be
directly excited to induce an intramolecular bonding or an
intermolecular bonding, and intramolecular crosslinking and
intermolecular crosslinking may be formed with the use of a
crosslinking agent. In order to combine each molecular structure, a
bonding residue (a photocrosslinkable residue) may be directly
excited to induce an photocrosslinking reaction, but in order to
more efficiently and more selectively cause coupling inside a
nanometric region in the molecular structure and coupling between
molecular structures, "spectrum sensitization" is preferably used.
By thus using spectrum sensitization, as shown in FIG. 2 and FIG.
4, a nano-particle and nano-wire of the molecular structure becomes
easily produced. In the preparation step, a sensitizer, so to
speak, is preferably added which is a molecule capable of
spectrally sensitizing a bonding residue (a photocrosslinkable
residue) by using the uniqueness of a dendrimer molecule capable of
including a foreign molecule or a foreign atom inside itself, as
described above. The detail of the sensitizer is described in
"Sensitizer", Kodansha scientific, (1987) by Tokumaru Katsuyuki and
Okawara Makoto. The mechanism of spectrum sensitization includes a
photoelectron transfer and a light energy transfer. The light
energy transfer is broadly divided into two types according to a
photoexcited state. One is a singlet energy transfer (Forster's
type) based on a dipole-dipole interaction, and the other is a
triplet energy transfer (Dexter's type) based on an electron
exchange interaction. The detail of the light energy transfer is
described in Modern Molecular Photochemistry, University Science
Books (1991) by N. Turro. The transfer distance of the
photoelectron transfer is about 0.4 to 2.0 nm, and the transfer
distances of the singlet and triplet energy transfers are
respectively about 1.0 to 10 nm and 0.3 to 1.0 nm. Among these
spectrum sensitization mechanisms, in the present invention, the
triplet energy transfer for spectrum sensitization in a nanometric
region is preferably used to optically combine the optically and/or
electronically functional molecular structures.
[0054] In the present specification, crosslinking means combining
two or more molecular structures by using a crosslinking agent, and
besides, combining bonding residues in the same molecular structure
or between the molecular structures without using the crosslinking
agent. In the present invention, a crosslinking agent means a
molecular for joining the bonding residues in a molecular structure
mutually. The crosslinking agent includes, for instance, butadiene,
pentadiene and a hydrocarbon having the bonding residue in the
molecular structure. The crosslinking agent combines molecular
structures mutually while controlling the spacing, by controlling
the length of itself, and provides a molecular aggregate having
regularity.
[0055] In a method of producing a molecular device according to the
present invention, a molecular structure or molecular aggregate
having a shell structure described bellow may be obtained as an
intermediate product.
[0056] The molecular structure having the shell structure
(hereafter also called a "nano-particle") is produced, for
instance, by crosslinking the bonding residues of a molecular
structure which has a higher atomic density in the periphery than
in the interior and has the bonding residues in the periphery, into
the shell. More specifically, the molecular structure having the
shell structure is a substance having the bonding residues existing
in the periphery of the molecular structure combined and form a
shell-like state. In particular, when the molecular structure has
not so high a density, and a large intermolecular distance between
the molecular structures, it mainly produces a nano-particle.
[0057] FIG. 1 shows a conceptual diagram of a nano-particle. FIG. 1
(a) shows a molecular structure (a dendrimer) 1. When the molecular
structure shown in FIG. 1 (a) is irradiated with light, the bonding
residue 6 inside the molecular structure is crosslinked (combined)
to form crosslinking part shown in FIG. 1 (b)-2. Thus, the
nano-particle 4 is formed which is the molecular structure having
the shell structure. The crosslinking reaction can be performed in
a solvent such as dichloromethane, and may be performed in a solid
phase as well.
[0058] One example of a nano-particle will be described with
reference to FIG. 2. A molecular structure 1 such as a dendrimer
has a sensitizer 3 in the periphery and the interior (FIG. 2 (a)).
The sensitizer absorbs energy by photoirradiation. The absorbed
energy by the sensitizer is transferred to the molecular structure
as shown by numeral 10. Then, in the molecular structure 1, bonding
residues are mutually combined (crosslinked) by the transferred
energy to form a crosslinking reaction part 9 (FIG. 2 (b)). Thus,
the crosslinking reaction part forms a shell and a consequent
nano-particle.
[0059] A molecular assembly having a plurality of molecular
structures combined, (hereafter also called a nano-wire) is
produced, for instance, by crosslinking the connective residues in
a molecular structure which has a higher atomic density in the
periphery than in the interior and has the connective residues in
the periphery, and combining the connective residues of the
adjacent molecular structures. The molecular structure according to
the present invention has a plurality of bonding residues, for
instance, inside the molecular. Then, when crosslinking proceeds, a
plurality of molecular structures are radially assembled. In
particular, when the molecular structure has a high density, and a
small intermolecular distance between the molecular structures, it
mainly produces a nano-wire.
[0060] For reference, a conceptual diagram of a nano-wire is shown
in FIG. 3. As for one example of producing a molecular aggregate,
as shown in FIG. 3 (a), the molecular structure 1 having the
bonding residues 6 in the periphery is irradiated with light. Then,
as shown in FIG. 3 (b), a crosslinkable residue in the molecular
structure 1 and a crosslinking agent 3 are crosslinked to obtain a
molecular aggregate 5.
[0061] In addition, when the crosslinking proceeds by an added
crosslinking agent, the bonding residue in the molecular structure
causes a crosslinking reaction with the crosslinking agent. In the
above step, by controlling the length of the crosslinking agent,
the molecular structures can assemble keeping distances among the
molecular structures controlled, to form a molecular aggregate.
[0062] A molecular aggregate according to the present invention,
(hereafter also called a nano-wire) is produced, for instance, by
crosslinking the bonding residues in a molecular structure which
has a higher atomic density in the periphery than in the interior
and has the bonding residues in the periphery, and joining the
bonding residues of the adjacent molecular structures. Another
example of a nano-wire is described with reference to FIG. 4. As
shown in FIG. 4 (a), the molecular structure 1 having bonding
residues in the periphery and the sensitizer 3 are irradiated with
light. The sensitizer absorbs energy due to photoirradiation. The
absorbed energy by the sensitizer is transferred to the molecular
structure as shown by numeral 10. Then, as shown in FIG. 4 (b), the
crosslinkable residue and the crosslinking agent 5 in the molecular
structure 1 are crosslinked to form the crosslinking reaction part
9 and provide the molecular aggregate 7 (FIG. 4 (b)).
[0063] In addition, when the crosslinking proceeds by addition of a
crosslinking agent, the bonding residue in the molecular structure
causes a crosslinking reaction with the crosslinking agent, and the
molecular structures can assemble keeping distances among the
molecular structures controlled, to form a molecular aggregate as
well.
[0064] A molecule device includes, for instance, devices with the
use of the above described nano-particle or nano-wire. A molecular
structure has various functions. Accordingly, by controlling the
aggregated form of the molecular structures in a molecule-level or
a nano-level, a molecular device can be obtained. For instance, by
crosslinking the bonding residues in the molecular structures while
controlling the positions, the three-dimensional structure of a
molecular aggregate can be controlled.
[0065] FIG. 5 shows a conceptual diagram of a photoconductive
nano-wire using a rod-shaped dendrimer, which is one example of a
molecular device according to the present invention.
[0066] FIG. 5 (a) shows a rod-shaped dendrimer molecule of which
the circumference is modified with bonding residues. When a
solution containing the dendrimer is irradiated with light, the
bonding residues in the dendrimer are combined, and a
photoconductive nano-wire which is a molecular device as shown in
FIG. 5 (b), can be obtained. The photoconductive nano-wire has
approximately equal formation rates of a free electron and a
positive hole, so that it behaves like an intrinsic semiconductor.
More specifically, by using such a molecular device, a
semiconductor element having the shape controlled in a nanometric
level can be obtained. The really obtained photoconductive
nano-wire had the electron mobility of about 1 cm.sup.2/V in the
axial direction and about 0.001 cm.sup.2/V in the radial
direction.
[0067] Furthermore, when the void of the photoconductive nano-wire
was doped with iodine, the electroconductivity of the
photoconductive nano-wire was drastically improved.
[0068] A molecular structure has various functions. Accordingly,
for instance, by combining such molecular structures one after
another toward a preferable direction through a crosslinking agent,
a molecular device can be obtained. The crosslinked part can be an
information transfer path when the molecular structure having
functionality transfers information such as an electric signal. By
such a method, a molecular device can be obtained which functions
as an information transfer system as if a neuron extends an axon to
other neurons. In addition, when a method of producing the
molecular device is applied between electrodes, molecular
structures are combined, and the molecular device capable of
transmitting information can be obtained. By using the molecular
device, a functional product can be obtained which uses the
molecular device consisting of combined molecular elements
(molecular structures) having functionality. FIG. 6 is a conceptual
diagram showing one example of a single electron transistor (SET)
of a molecular device which can be produced with such a production
method. In FIG. 6, numeric 1 expresses a molecular structure which
can function as a molecular element, numeric 5 expresses a
crosslinking agent, numeric 9 expresses a crosslinking reaction
part, and numeric 11 expresses an electrode. A SET shown in FIG. 6
was produced as described below. At first, an electrode 11 having a
spacing of about 50 nm was prepared. The spacing of the electrode
11 can be controlled to about 10 nm to 1 .mu.m. Then, a dendrimer
having bonding residues at both poles (in opposed positions), and a
solution containing a sensitizer and a crosslinking agent were
prepared so as to combine the electrodes. Then, the solution
containing the dendrimer was irradiated with light. Then, a
molecular device (SET) as shown in FIG. 6 could be obtained. When
voltage was applied on the molecular device, a phenomenon showing a
stepped current-voltage characteristic (a Coulomb blockade
phenomenon) was observed. From the result, it was found that the
crosslinking agents combined mutually by photoirradiation functions
as a tunnel layer.
[0069] FIG. 7 is a conceptual diagram showing one example of a
T-type optoelectronic element (TOED) which is another molecular
device according to the present invention.
[0070] One example of methods of producing TOED is now described
below. At first, a substrate made of mica was prepared. The
substrate may be an insulator such as gold, copper, platinum and
mica. Subsequently, the substrate was immersed into a solution
containing four types of molecular structures A, B, C and D, and a
sensitizer. In the above solution, a crosslinking agent may be
contained. The molecular structure A has such a bonding residue in
the first position as to be combined with a certain bonding residue
in the molecular structure B. The molecular structure A may have
such a bonding residue in the tenth position as to be combined with
a certain bonding residue in the molecular structure C. (In this
case, the obtained molecular device is not a TOED but a continuum
of a T-type optoelectronics.) The molecular structure B has each
bonding residue in the first position, the fifth position and the
tenth position as to be combined with each certain bonding residue
respectively in the molecular structures C, D and A. The molecular
structure B may have such a bonding residue in the 15th position as
to be combined with a certain bonding residue in the molecular
structure D. (In this case, the obtained molecular device is not a
TOED but a continuum of a T-type optoelectronics.)
[0071] When the solution was irradiated with light, a molecular
device was formed on the substrate.
[0072] When an optical signal was input in the molecular structure
A out of the molecular devices, an output was observed from the
molecular structure B after 30 picoseconds.
[0073] On the other hand, when the molecular structure D was
oxidized and then an optical signal was input in the molecular
structure A, the output was not obtained from the molecular
structure B.
[0074] In addition, by using a molecular device according to the
present invention, a molecular integrated circuit, for instance,
described in Japanese Patent Laid-Open No. 2001-44413, can be
manufactured. The molecular integrated circuit with the use of the
molecular device according to the present invention, can be used as
a NAND circuit, a NOR circuit, an inverter circuit, a random access
memory cell and a read only memory cell, as in the case of a
molecular integrated circuit described in Japanese Patent Laid-Open
No. 2001-44413. In the present invention, because a molecular
device can be constructed by using a photosensitization reaction,
molecular devices can be more precisely and speedily produced.
PRODUCTION EXAMPLE 1
Method of Synthesizing Dendrimer having Cinnamic Acid Amide Residue
in Terminal
[0075] Into a dichloromethane solution of a poly (propyleneimine)
dendrimer (1.0 g, 3.2 mmol, made by Aldrich Corporation) of the
first generation (n=1 in FIG. 8) containing a catalytic quantity of
triethylamine, a solution of trans-cinnamyl chloride (0.63 g, 3.7
mmol, made by Aldrich Corporation) was dropped, and the resultant
solution was stirred at 0.degree. C. for one hour and then at room
temperature for 40 hours. This reaction liquid was diluted with
dichloromethane, was cleaned sequentially with ion-exchange water,
an aqueous solution of sodium carbonate and an aqueous solution of
sodium chloride, and was dried with magnesium sulfate. After
filtration, dichloromethane was removed by an evaporator. The crude
product was dialyzed and reprecipitated repetitively for three
times, and was dried under a reduced pressure. Then, a white solid
was obtained.
[0076] Each poly (propyleneimine) dendrimer of the third generation
and the fifth generation (respectively n=3 and 5 in FIG. 8) was
also synthesized and refined with a similar method to the above
described method.
[0077] Various physical properties of thus synthesized dendrimer
are shown in Table 1 and Table 2. TABLE-US-00001 TABLE 1 A
plurality of physical properties of synthesized dendrimer Results
of measurement on weight average molecular weight and molecular
weight distribution by size exclusion chromatography Weight average
Molecular weight Calculated Dendrimer molecular weight distribution
value First generation 905 1.02 837 Third generation 4103 1.01 3768
Fifth generation 16084 1.02 15497
[0078] TABLE-US-00002 TABLE 2 Results of measurement of melting
point by differential scanning calorimetry First Third Fifth
Dendrimer generation generation generation Melting point (.degree.
C.) 150 103 93
EXAMPLE 1
Production of Nano-Particle
EXAMPLE 1-1
[0079] With the use of polypropylene imine dendrimer of the first
generation (n=1) having residues of cinnamamide in the periphery of
the molecular as shown in FIG. 8, the following experiment was
carried out. A plurality of dichloromethane dilute solutions
containing 3.0.times.10-5 (mol/L) of the dendrimer having
cinnamamide by molar unit of cinnamamide in the dendrimer were
prepared and were put in quartz cells having a dimension of 1.0 cm
per side. The light having a wavelength of 313 nm which was taken
out from a mercury xenon lamp having an output of 200 W, irradiated
the previously prepared solution. With the photoirradiation, the
absorption bands around 280 nm originated in the residue of
cinnamamide decreased. The absorption spectrum after the
photoirradiation was measured, and the abundance ratio of each
trans isomer, cis isomer and associated body of the cinnamamide
residue was calculated. The result is shown in Table 3. Here, the
associated body means a product in which the cinnamamide residues
are mutually combined.
EXAMPLE 1-2
[0080] As in the Example 1-1 except that the polypropylene imine
dendrimer of the third generation (n=3 in FIG. 8) was employed, an
experiment was carried out. The result is shown in Table 3.
EXAMPLE 1-3
[0081] As in the Example 1-1 except that the polypropylene imine
dendrimer of the fifth generation (n=5 in FIG. 8) was employed, an
experiment was carried out. The result is shown in Table 3.
TABLE-US-00003 TABLE 3 Results of measurement of absorption
spectrum after photoirradiation in dilute solution of propylene
imine dendrimer Quantity of Trans Cis exposure energy isomer isomer
Associated (J/cm.sup.2) (%) (%) body (%) First 0.4 86 11 3
generation 2.0 56 39 5 10 40 48 12 20 30 53 17 30 21 59 20 Third
0.4 87 9 4 generation 2.0 62 25 13 10 40 34 26 20 24 39 37 30 19 40
41 Fifth 0.4 83 l0 7 generation 2.0 66 17 17 10 46 21 33 20 34 24
42 30 24 26 50
[0082] From the Table 3, it was found that in the bonding dendrimer
molecule associated with the present invention, as the quantity of
exposure energy in a dilute solution increases, the ratio of the
trans isomer of the cinnamamide residue decreases; whereas the
ratio of the cis isomer and the associated body increases. It was
found that particularly the increasing ratio of the associated body
strongly depends on the generation of the dendrimer molecule, and
the dendrimer of the fifth generation effectively forms the
associated body. A fully irradiated solution with light was
subjected to gel permeation chromatography, and the retention times
before and after the photoirradiation were measured to prove that
they were not changed. It means that the molecular weight of the
dendrimer was maintained before and after the photoirradiation.
Accordingly, in the solution of the dilute concentration, a
coupling reaction occurred not between molecules but inside the
dendrimer molecule, which means that a nano-particle was produced
in the dilute solution. The nano-particle is considered to form in
such a manner that the cinnamyl residues in a polypropylene imine
dendrimer were photoexcitated, and sequentially caused dimerization
(intramolecular coupling) with the adjacent cinnamyl residues.
Because with the increase of the generation of a polypropylene
imine dendrimer, the density of the cinnamyl residue increases, the
ratio of the associated body consisting of mutually combined
cinnamyl residues also increases with the increase of the
generation of the dendrimer.
COMPARATIVE EXAMPLE 1
[0083] Instead of the bonding dendrimer used in the above described
Example 1-1, cinnamamide was employed and the dilute solution was
prepared. Then the solution was irradiated with light as in the
Example 1. The result is shown in Table 4. TABLE-US-00004 TABLE 4
Results of measurement of absorption spectrum after
photoirradiation in a dilute cinnamamide solution Quantity of Trans
Cis exposure energy isomer isomer Associated (J/cm.sup.2) (%) (%)
body (%) Cinnamamide 0.4 82 16 2 2.0 40 56 4 10 23 73 4 20 23 72 5
30 21 74 5
[0084] The comparison of the above described Table 3 with the Table
4 makes it clear that the formation rate of the associated body of
cinnamamide is greatly different from that of the crosslinkable
dendrimer, and is extremely low.
EXAMPLE 2
Production of Nano-Particle in Solid Layer
EXAMPLE 2-1
[0085] With the use of a polypropylene imine dendrimer of the first
generation (n=1), the following experiment was carried out. So as
to have the ratio of a cinnamamide unit to a methyl methacrylate
monomer unit in a dendrimer controlled to 1:10, a solution was
prepared which contains the crosslinkable dendrimer diluted and
dispersed in poly (methyl methacrylate). Each aliquot of the
dichloromethane solution thus prepared was applied onto a glass
substrate with a spin coating method. The solution was dried and
solidified, then the light having the wavelength of 313 nm was
taken out from a mercury xenon lamp having the output of 200 W, and
the glass substrate was irradiated with it. With the
photoirradiation, the absorption bands around 280 nm originated in
the residue of cinnamamide was decreased. The absorption spectrum
after the photoirradiation was measured, and the abundance ratio of
each trans isomer, cis isomer and associated body of the
cinnamamide residue was calculated. The result is shown in Table
5.
EXAMPLE 2-2
[0086] As in the Example 2-1 except that the polypropylene imine
dendrimer of the third generation (n=3 in FIG. 8) was employed, an
experiment was carried out. The result is shown in Table 5.
EXAMPLE 2-3
[0087] As in the Example 2-1 except that the polypropylene imine
dendrimer of the fifth generation (n=5 in FIG. 8) was employed, an
experiment was carried out. The result is shown in Table 5.
TABLE-US-00005 TABLE 5 Results of measurement of absorption
spectrum after photoirradiation in solid layers of propylene imine
dendrimer Quantity of Trans Cis Photocross- exposure energy isomer
isomer linked (J/cm.sup.2) (%) (%) body (%) First 0.2 90 9 1
generation 1.0 72 21 7 5.0 46 28 26 9.0 34 29 37 15 27 28 45 Third
0.2 89 7 4 generation 1.0 67 17 16 5.0 36 29 35 9.0 24 31 45 15 16
32 52 Fifth 0.2 88 6 6 generation 1.0 57 20 23 5.0 28 27 45 9.0 18
27 55 15 12 28 60
[0088] It was found from Table 5 that as for the crosslinkable
dendrimer molecule associated with the present invention, the
increasing ratio of the associated body of cinnamyl residues
strongly depends on the generation of the dendrimer molecule in a
solid as well, as seen in a photochemical reaction behavior in a
dilute solution in the above described Example 1, and the dendrimer
of the fifth-generation effectively forms a photocrosslinked body.
In addition, it was judged from ultraviolet-visible absorption
spectrum measurement that when the thin film of a dendrimer/poly
(methyl methacrylate) after being irradiated with light is immersed
in dichloromethane of a solvent used in a spin coating, the film is
removed from a glass substrate.
COMPARATIVE EXAMPLE 2
[0089] Instead of the crosslinkable dendrimer used in the above
described Example 2, cinnamamide was employed and diluted in poly
(methyl methacrylate) to make thin films. Then the thin films were
irradiated with light as in the Example 2. The results are shown in
Table 6. TABLE-US-00006 TABLE 6 Results of measurement of
absorption spectrum after photoirradiation in solid layer of
cinnamamide Quantity of Trans Cis exposure energy isomer isomer
Associated (J/cm.sup.2) (%) (%) body (%) Cinnamamide 0.2 80 19 1
1.0 54 45 1 5.0 40 55 5 9.0 38 57 5 15 31 64 5
[0090] The comparison of the above described Table 5 with the Table
6 makes it clear that in the photochemical behavior in a solid as
well as in a dilute solution, the formation rate of the associated
body of cinnamamide is greatly different from that of a
crosslinkable dendrimer, and is extremely low.
EXAMPLE 3
[0091] Except that a polypropylene imine dendrimer molecule was
solely used instead of the polypropylene imine dendrimer molecule
diluted and dispersed in poly (methyl methacrylate), a similar
experiment to the Example 2-1, the Example 2-2 and the Example 2-3
was performed. Though a glass substrate was immersed in
dichloromethane, a film remained on the glass substrate. This
occurred because in the present example, the polypropylene imine
dendrimer molecular became a macromolecule insoluble in
dichloromethane.
[0092] It is clear from the Example 2 and the Example 3 that in a
dendrimer/poly (methyl methacrylate) diluted film a cinnamyl
residue is a core of an intramolecular bonding inside one molecule
of the dendrimer, and that in a dendrimer-rich thin film, an
intermolecular bonding among dendrimer proceeds. In addition, it is
clear that in a solid as well, a nano-particle and a nano-wire can
be produced.
EXAMPLE 4-1
[0093] In a dichloromethane solution of the polypropylene imine
dendrimer of the first-generation (n=1 in general formula (I)
having a cinnamamide residue in the periphery of the molecule,
4,4'-bis (dimethylamino) benzophenone was each mixed as a
sensitizer, and the solute was reprecipitated in a surplus quantity
of hexane. The precipitate was dialyzed with dichloromethane and
was reprecipitated again.
[0094] The dichloromethane solution of the polypropylene imine
dendrimer of the first generation which includes 4,4'-bis
(dimethylamino) benzophenone was irradiated with the light having
the wavelength of 365 nm which was taken out from a mercury xenon
lamp with an output of 200 W. In the above step, the temperature of
the solution was room temperature.
[0095] A cinnamamide residue does not absorb light of 365 nm, but
4,4'-bis (dimethylamino) benzophenone has an absorption band in the
vicinity of 365 nm. It was found from the result of
ultraviolet-visible absorption spectrum measurement that the number
of molecules of 4,4'-Bis (dimethylamino) benzophenone included in
the dendrimer was nil for the first generation. The dichloromethane
solution containing the dendrimer, which was prepared in the above
described method, was thoroughly irradiated with the light of 365
nm, but no change was observed in ultraviolet-visible absorption
spectra.
EXAMPLE 4-2
[0096] Except that the polypropylene imine dendrimer of the third
generation (n=3 in general formula (I)) was employed, a similar
experiment to the Example 4-1 was carried out to produce a
molecular aggregate.
[0097] As a result of ultraviolet-visible absorption spectral
measurement, it was found that the number of molecules of 4,4'-bis
(dimethylamino) benzophenone included in the dendrimer was three
for the third generation.
EXAMPLE 4-3
[0098] Except that the polypropylene imine dendrimer of the fifth
generation (n=5 in general formula (I)) was employed, a similar
experiment to the Example 4-1 was carried out to produce a
molecular aggregate.
[0099] As a result of ultraviolet-visible absorption spectrum
measurement, it was found that the number of molecules of 4,4'-bis
(dimethylamino) benzophenone included in the dendrimer was eight
for the fifth generation.
EXAMPLE 5-1
[0100] So as to make the ratio of a cinnamamide unit to a methyl
methacrylate monomer unit in a dendrimer controlled to 1:10, a
solution was prepared which has the photocrosslinkable dendrimer
molecules (the third generation polypropylene imine dendrimer)
including 4,4'-Bis (dimethylamino) benzophenone diluted and
dispersed in poly (methyl methacrylate).
[0101] The poly (methyl methacrylate) solution prepared in such a
method was applied onto a glass substrate with a spin coat method.
The glass substrate after being coated with the solution, was dried
at room temperature to form a solid containing the dendrimer
thereon.
[0102] The light having the wavelength of 365 nm was taken out from
a mercury xenon lamp having the output of 200 W, and the glass
substrate was irradiated with the light. With progress of the
photoirradiation, the absorption bands around 280 nm originating
from a cinnamamide residue decreased. The absorption spectrum after
the photoirradiation was measured, and the abundance ratio of each
trans isomer, cis isomer and photocrosslinked body of the
cinnamamide residue was calculated. The result is shown in Table
7.
EXAMPLE 5-2
[0103] Except that the polypropylene imine dendrimer of the fifth
generation was employed, a similar experiment to the Example 5-1
was carried out to produce a molecular aggregate. As in the Example
5-1, the absorption spectrum after the photoirradiation was
measured, and the abundance ratio of each trans isomer, cis isomer
and photocrosslinked body of the cinnamamide residue was
calculated. The result is shown in Table 7. TABLE-US-00007 TABLE 7
Isomeric ratios in the third and fifth generation dendrimers after
photoirradiation Quantity of Trans Cis Photocross- exposure energy
isomer isomer linked (J/cm.sup.2) (%) (%) body (%) Third 0.1 76 13
11 generation 0.4 54 19 27 1.0 32 22 46 2.0 18 24 58 3.0 13 24 63
Fifth 0.1 81 14 5 generation 0.4 63 17 20 1.0 44 20 36 2.0 27 24 49
3.0 20 26 54
[0104] From a result shown in Table 7, it is clear that with
photoirradiation, the formation ratio of the trans isomer of the
cinnamamide residue decreased, and the formation ratios of the cis
isomer and the photcrosslinked body increased.
[0105] In addition, the comparison result of the formation ratios
of the photocrosslinked body of cinnamamide between the dendrimers
of the third generation and of the fifth generation, made it clear
that the ratio in the dendrimer of the third generation is higher
than that in the dendrimer of the fifth-generation. A dendrimer
including 4,4'-bis (dimethylamino) benzophenone could form a
photocrosslinked body by the low exposure energy of 3.0 J/cm.sup.2
in the wavelength of 365 nm. The exposure energy of 3.0 J/cm.sup.2
is lower than that in producing a photocrosslinked body by directly
exciting a cinnamamide residue with the light having the wavelength
of 313 nm. This is considered to happen because a sensitizer
absorbs light, and due to the light energy absorbed by the
sensitizer, connective residues have been effectively combined
(crosslinked). Thus, it can be said that the present invention, in
spite of using an exposure light of low energy, has succeeded in
forming a structure of single molecular highly sensitively by
photocrosslinking.
EXAMPLE 5
[0106] A dendrimer/poly (methyl methacrylate) thin-film after
photoirradiation was immersed in dichloromethane which is a solvent
used for a spin coating. As a result, it was judged from
ultraviolet-visible absorption spectrum measurement that the film
is removed from the surface of the glass substrate. From the fact,
it is considered that when a dendrimer dilute solution is
irradiated with light, a polymer is not formed. This is considered
to happen because the bonding residues in the dendrimer were
combined by photoirradiation to mainly form nano-particles.
EXAMPLE 6
[0107] A thin film containing only photocrosslinkable dendrimers
was fully irradiated with the light of 365 nm, and was immersed in
dichloromethane as in the case described above. As a result, the
film remained on a glass substrate. From the fact, it is considered
that when the thin film containing only dendrimers was irradiated
with light, the polymerization proceeded. This is considered to
happen because a photocrosslinking reaction proceeded among
dendrimer molecules by the photoirradiation, and nano-wires were
mainly formed.
INDUSTRIAL APPLICABILITY
[0108] According to the present invention, a nano-particle and a
nano-wire can be effectively produced.
[0109] According to the present invention, a molecular device can
be adequately produced by a bottomed-up design.
[0110] A nano-particle and a nano-wire according to the present
invention can be used as a liquid crystal material, a functional
material, an electronic functional material, a catalyst, a
nano-level electronic element, a nano-level FET, a toner raw
material, additives for plastics such as an antistatic agent and a
charge donor agent, and a drug delivery system.
[0111] A nano-wire according to the present invention can be used
for a superdense memory material and a light emitting element,
which take advantage of the periodicity of a level of a plurality
of nanometers to a plurality of hundreds of nanometers.
* * * * *