U.S. patent application number 12/809367 was filed with the patent office on 2011-12-08 for platinum (ii) di (2-pyrazolyl) benzene chloride analogs and uses.
This patent application is currently assigned to Arizona Board of Regents for and on Behalf of Arizona State University. Invention is credited to Jian Li, Zixing Wang.
Application Number | 20110301351 12/809367 |
Document ID | / |
Family ID | 40825058 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110301351 |
Kind Code |
A1 |
Li; Jian ; et al. |
December 8, 2011 |
Platinum (II) Di (2-Pyrazolyl) Benzene Chloride Analogs and
Uses
Abstract
Synthesis of platinum(II) di(2-pyrazolyl)benzene chloride and
analogs includes forming a 1,3-di-substituted benzene including two
aromatic five-membered heterocycles, and reacting the
1,3-di-substituted benzene with an acidic platinum-containing
solution to form a luminescent platinum(II) complex. The
luminescent platinum(II) complex is capable of emitting blue and
white light and can be used as an emitter in a light emitting
device.
Inventors: |
Li; Jian; (Phoenix, AZ)
; Wang; Zixing; (Shanghai, CN) |
Assignee: |
Arizona Board of Regents for and on
Behalf of Arizona State University
Scottsdale
AZ
|
Family ID: |
40825058 |
Appl. No.: |
12/809367 |
Filed: |
December 19, 2008 |
PCT Filed: |
December 19, 2008 |
PCT NO: |
PCT/US2008/087847 |
371 Date: |
August 17, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61016155 |
Dec 21, 2007 |
|
|
|
Current U.S.
Class: |
546/4 ;
548/103 |
Current CPC
Class: |
H01L 51/0087 20130101;
C09K 2211/1044 20130101; H01L 51/5012 20130101; C07F 15/0086
20130101; Y02B 20/181 20130101; C09K 11/06 20130101; C09K 2211/1007
20130101; C09K 2211/1029 20130101; C09K 2211/1037 20130101; C09K
2211/185 20130101; Y02B 20/00 20130101 |
Class at
Publication: |
546/4 ;
548/103 |
International
Class: |
C07F 15/00 20060101
C07F015/00 |
Claims
1. A luminescent compound comprising: ##STR00012## wherein
##STR00013## is an aromatic heterocycle, the six-membered aromatic
ring is a phenyl or pyridinyl group, and W is --Cl or
##STR00014##
2. The compound of claim 1, wherein ##STR00015## is selected from
the group consisting of ##STR00016##
3. The compound of claim 1, wherein the compound comprises:
##STR00017##
4. The compound of claim 1, wherein the compound is
phosphorescent.
5. The compound of claim 1, wherein the compound is capable of
emitting light in the blue range of the visible spectrum.
6. The compound of claim 1, wherein the compound is capable of
emitting white light.
7. (canceled)
8. A light emitting device comprising a luminescent compound
comprising: ##STR00018## wherein ##STR00019## is an aromatic
heterocycle, the six-membered aromatic ring is a phenyl or
pyridinyl group, and W is --Cl or ##STR00020##
9. The device of claim 8, wherein ##STR00021## is selected from the
group consisting of ##STR00022##
10. The device of claim 8, wherein the compound is
phosphorescent.
11. The device of claim 8, wherein the compound is capable of
emitting light in the blue range of the visible spectrum.
12. The device of claim 8, wherein the compound is capable of
emitting white light.
13. The device of claim 8, wherein the compound comprises:
##STR00023##
14. The device of claim 8, wherein the device is an organic light
emitting device.
15. (canceled)
16. A method of making a platinum(II) complex, the method
comprising: (a) forming an aromatic 1,3-di-substituted six-membered
ring, wherein each substituent is an aromatic five-membered
heterocycle; and (b) reacting the 1,3-di-substituted aromatic
six-membered ring with an acidic platinum-containing solution to
form the platinum(II) complex.
17. The method of claim 16, wherein the aromatic five-membered
heterocycles are pyrazolyl groups.
18. The method of claim 16, wherein the aromatic five-membered
heterocycles are selected from the group consisting of substituted
pyrazolyl, imidazolyl, substituted imidazolyl, thiazolyl, and
substituted thiazolyl groups.
19. The method of claim 18, wherein an atom in the six-membered
ring is bonded to a heteroatom in each heterocycle.
20. The method of claim 19, wherein the six-membered ring is bonded
to a nitrogen atom or a sulfur atom in each heterocycle.
21. The method of claim 16, wherein the two aromatic heterocycles
are the same.
22. The method of claim 16, wherein the platinum(II) complex
comprises a platinum atom bonded to a carbon atom and two nitrogen
atoms.
23. The method of claim 16, wherein the aromatic six-membered ring
is benzyl group.
24. The method of claim 23, wherein the platinum(II) complex is
platinum(II) di(2-pyrazolyl)benzene chloride.
25. The method of claim 23, wherein the benzene is fluorinated,
difluorinated, or methylated.
26. The method of claim 16, wherein the aromatic six-membered ring
is a pyridinyl group.
Description
PRIORITY CLAIM AND RELATED PATENT APPLICATION
[0001] This document claims priority from U.S. Patent Provisional
Application Ser. No. 61/016,155 entitled "Platinum(II)
Di(2-Pyrazolyl) Benzene Chloride Analogs and Uses" and filed on
Dec. 21, 2007, the entire contents of which are incorporated herein
by reference as part of the disclosure of this document.
TECHNICAL FIELD
[0002] This invention relates to platinum(II)
di(2-pyrazolyl)benzene chloride and analogs, and more particularly
to the synthesis and use thereof.
BACKGROUND
[0003] As depicted in FIG. 1, an organic light-emitting device
(OLED) 100 may include a layer of indium tin oxide (ITO) as an
anode 102, a layer of hole-transporting materials (HTL) 104, a
layer of emissive materials (EML) 106 including emitter(s) and
host(s), a layer of electron-transporting materials (ETL) 108, and
a metal cathode layer 110 on substrate 112. The emission color of
OLED 100 may be determined by the emission energy (optical energy
gap) of the emitter(s) in the layer of emissive materials.
Phosphorescent OLEDs (i.e., OLEDs with phosphorescent emitters) may
have higher device efficiency than fluorescent OLEDs (i.e., OLEDs
with fluorescent emitters). Some emitters for blue phosphorescent
OLEDs include iridium--a relatively scarce element--in the form of
cyclometalated iridium complexes.
SUMMARY
[0004] In one aspect, a luminescent compound has the generic
formula
##STR00001##
where
##STR00002##
is an aromatic heterocycle and where W is --Cl or
##STR00003##
The six-membered ring in this generic formula denotes benzene or
pyridine.
[0005] In another aspect, a light emitting device includes the
luminescent compound shown above.
[0006] In certain implementations,
##STR00004##
is selected from the group consisting of
##STR00005##
In certain implementations, the luminescent compound is
platinum(II) di(2-pyrazolyl)benzene chloride, with the formula:
##STR00006##
[0007] In some implementations, the luminescent compound is
phosphorescent. The compound is capable of emitting light in the
blue range of the visible spectrum. In some cases, the compound is
capable of emitting white light. The light emitting device may be
an organic light emitting device.
[0008] In another aspect, a method of making a platinum(II) complex
includes forming a 1,3-di-substituted aromatic six-membered ring
with two aromatic five-membered heterocycles, and reacting the
1,3-di-substituted six-membered ring with an acidic
platinum-containing solution to form the platinum(II) complex.
[0009] In some implementations, the aromatic five-membered
heterocycles are selected from the group consisting of pyrazolyl,
substituted pyrazolyl, imidazolyl, substituted imidazolyl,
thiazolyl, and substituted thiazolyl. In certain implementations,
the benzene is fluorinated, difluorinated, or methylated.
Fluorinating the benzene ring may increase the emission energy,
shifting the emission toward the blue end of the visible spectrum.
The benzene may be bonded to a heteroatom, such as a nitrogen atom
or a sulfur atom, in the heterocycle. The platinum atom in the
platinum(II) complex may be bonded to a carbon atom and two
nitrogen atoms. In some embodiments, the platinum(II) complex is
platinum(II) di(2-pyrazolyl)benzene chloride. In certain
implementations, the aromatic six-membered ring is benzene or
pyridine. In some cases, when the six-membered ring is pyridine, an
increase in the emission energy may result.
[0010] Phosphorescent blue OLEDs with the platinum complexes
described herein as emitters can be produced at low cost and
provide operationally stable displays.
[0011] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0012] FIG. 1 illustrates an organic light emitting device
(OLED).
[0013] FIG. 2 shows precursors for platinum(II)
di(2-pyrazolyl)benzene chloride and analogs.
[0014] FIG. 3 shows platinum(II) di(2-pyrazolyl)benzene and
analogs.
[0015] FIG. 4 shows a room temperature emission spectrum of
platinum(II) di(2-pyrazolyl)benzene chloride in
dichloromethane.
[0016] FIG. 5 shows room temperature and 77K emission spectra of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)benzene chloride in
solution.
[0017] FIG. 6 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)benzene chloride in thin
film of poly(methyl methacrylate) (PMMA).
[0018] FIG. 7 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)benzene phenoxide in a
thin film of poly(carbonate).
[0019] FIG. 8 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)toluene chloride in a thin
film of poly(methyl methacrylate) (PMMA).
[0020] FIG. 9 shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)benzene chloride in a solution of
dichloromethane.
[0021] FIG. 10 shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)benzene chloride in a thin film
of poly(methyl methacrylate) (PMMA).
[0022] FIG. 11A shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)toluene chloride in a thin film
of poly(methyl methacrylate) (PMMA).
[0023] FIG. 11B shows a 77K emission spectrum of platinum(II)
di(methyl-imidazolyl)pyridine chloride in a solution of
2-methyl-tetrahydrofuran.
[0024] FIG. 12 shows a room temperature emission spectrum of
platinum(II) di(thiazolyl)(4,6-difluoro-benzene) chloride in a
solution of dichloromethane.
DETAILED DESCRIPTION
[0025] The platinum complexes described herein can be used as
emitters for OLEDs, absorbers for solar cells, luminescent labels
for bio-applications, and the like. Blue phosphorescent OLEDs may
include platinum complexes with high band-gap ligands, including
the five-membered rings depicted herein.
[0026] Platinum(II) di(2-pyrazolyl)benzene chloride and analogs may
be represented as:
##STR00007##
in which:
##STR00008##
is an aromatic heterocycle,
and W can be --Cl or
##STR00009##
[0027] The aromatic six-membered ring in this generic formula
denotes benzene or pyridine. The aromatic five-membered heterocycle
can be, for example, substituted pyrazolyl, imidazolyl, substituted
imidazolyl, thiazolyl, and substituted thiazolyl ligands shown
below:
##STR00010##
In some embodiments, the luminescent compound is platinum(II)
di(2-pyrazolyl)benzene chloride, shown below:
##STR00011##
In some cases, the benzene ring is substituted, such as fluorinated
or methylated in one or more positions. Fluorinating the benzene
ring increases the emission energy, shifting the emission toward
the blue end of the visible spectrum. In certain cases, the
six-membered ring is a pyridyl ring rather than benzene.
[0028] Platinum(II) di(2-pyrazolyl)benzene chloride and analogs
described herein may be prepared from the ligands depicted in FIG.
2. Synthesis of the ligands is described below.
[0029] HL.sup.1: After standard cycles of evacuation and back-fill
with dry and pure nitrogen, an oven-dried Schlenk flask equipped
with a magnetic stir bar was charged with Cu.sub.2O (0.1 mmol, 10
mol %), syn-2-pyridinealdoxime (0.4 mmol, 20 mol %), the pyrazole
(2.5 mmol), Cs.sub.2CO.sub.3 (5.0 mmol), and the 1,3-dibromobenzene
(1.0 mmol), and anhydrous and degassed acetonitrile (20 mL). The
flask was stirred in an oil bath, and refluxed for 3 days. The
reaction mixture was allowed to cool to room temperature, diluted
with dichloromethane and filtered through a plug of CELITE.RTM.
(World Minerals Inc., Santa Barbara, Calif.), the filter cake being
further washed with dichloromethane (20 mL). The filtrate was
concentrated under vacuo to yield a residue, which was purified by
flash column chromatography on silica gel to obtain the pure
product HL.sup.1 in 80% yield. .sup.1H NMR (CDCl.sub.3): 6.51 (dd,
2H), 7.52 (t, 1H), 7.62 (dd, 2H), 7.76 (d, 2H), 8.02 (d, 2H), 8.10
(s, 1H).
[0030] HL.sup.2: HL.sup.2 was synthesized in 64% yield using the
same procedure as HL.sup.1 except that 1,3-diiodobenzene was used
as starting material. .sup.1H NMR (CDCl.sub.3): 2.6 (s 12H), 6.0
(s, 2H), 7.42 (dd, 2H), 7.51 (t, 2H), 7.55 (t, 2H).
[0031] HL.sup.3:
1,3-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene (1.0
mmol), Pd(OAc).sub.2 (0.05 equiv), PPh.sub.3 (0.2 equiv),
1-methyl-2-iodoimidazole (2.5 mmol) were resolved in
dimethoxyethane/2M K.sub.2CO.sub.3 aqueous solution (20 mL, 1:1)
under nitrogen atmosphere. The mixture was heated and refluxed for
24 h. After being cooled to room temperature, the reaction mixture
was diluted with EtOAc, and poured into a brine solution. The
organic layer was separated, and washed with the water, dried,
filtered, and the filtrate was concentrated under reduced pressure.
The residue was purified by column chromatography on silica gel to
obtain the pure product HL.sup.3 in 34% yield. .sup.1H NMR
(CDCl.sub.3): 3.72 (s 6H), 7.12 (d, 2H), 7.47 (t, 1H), 7.48 (d,
2H), 7.56 (s, 1H), 7.72 (d, 2H).
[0032] HL.sup.4: HL.sup.4 was synthesized in 40% yield using the
same procedure as HL.sup.3 except that
1,3-difluoro-4,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene
was used as starting material instead of
1,3-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-benzene.
.sup.1H NMR (CDCl.sub.3): 3.63 (s, 6H), 7.09 (t, 1H), 7.13 (d, 2H),
7.35 (t, 1H), 7.60 (d, 2H).
[0033] HL.sup.5: HL.sup.5 was synthesized in 25% yield using the
same procedure as HL.sup.3 except that 2-bromothiozole was used as
starting material instead of 1-methyl-2-iodoimidazole. .sup.1H NMR
(CDCl.sub.3): 7.13 (t, 1H), 7.49 (d, 2H), 7.98 (d, 2H), 9.23 (t,
1H).
[0034] HL.sup.6: HL.sup.6 was synthesized in 65% yield using the
same procedure as HL.sup.1 except that imidazole was used as
starting material. .sup.1H NMR (DMSO): 7.26 (2H), 7.34 (2H), 7.41
(1H), 7.43 (2H), 7.62 (1H), 7.92 (2H).
[0035] HL.sup.7: Methyl iodide (3 equiv) was syringed into a 50 mL
round-bottomed flask charged with HL.sup.6 (10 mmol) and DMSO (30
mL). The reaction was stirred under nitrogen in room temperature
for 48 h. The mixture was poured into EtOAc (60 mL), and the white
precipitate was formed, filtered, washed with ether, and air-dried
to obtain HL.sup.7 in 85% yield. .sup.1H NMR (DMSO): 3.99 (s, 6H),
7.97-8.00 (m, 3H), 8.00 (s, 2H), 8.31 (s, 1H), 8.37 (s, 2H), 9.89
(s, 2H).
[0036] HL.sup.8: HL.sup.8 was synthesized in 60% yield using the
same procedure as HL.sup.1 except that 1,3-diiodotoluene was used
as starting material. .sup.1H NMR (CDCl.sub.3): 2.28 (s, 6H), 2.32
(s, 6H), 2.44 (s, 3H), 5.98 (s, 2H), 7.26-7.28 (m, 3H).
[0037] HL.sup.9: A mixture of 3,5-diiodotoluene (1.1 g, 3.0 mmol),
1-methylimidazole (7.5 mmol), Pd(OAc).sub.2 (5 mg, 0.01 mmol), KI
(2.0 g, 12 mmol), and CuI (2.4 g, 12.2 mmol) in degassed DMF (12
mL) was heated under Ar at 140.degree. C. for 10 days. After
cooling to room temperature, the mixture was poured into NH.sub.3
solution (10%, 50 mL), and CH.sub.2Cl.sub.2 (40.times.3 mL) was
added. The organic phase was separated and dried (MgSO.sub.4), and
the solvent was evaporated. The crude product was purified by
chromatograph (silica gel; ethyl acetate/methanol, 4:1) to give
ligand HL.sup.9 as a light yellow solid (40%). .sup.1H NMR
(CDCl.sub.3): .delta.2.44 (s, 3H), 3.78 (s, 6H), 6.97 (d, 2H), 7.11
(d, 2H), 7.52 (s, 2H), 7.60 (s, 1H).
[0038] HL.sup.10: HL.sup.10 was synthesized in 35% yield using the
same procedure as HL.sup.1 except that 1,3-dibromopyridine was used
as starting material. .sup.1H NMR (CDCl.sub.3): 2.3 (s, 6H), 2.4
(s, 6H), 6.06 (s, 2H), 8.00 (t, 1H), 8.71 (d, 2H).
[0039] HL.sup.11: HL.sup.11 was synthesized in 35% yield using the
same procedure as HL.sup.9 except that 1,3-dibromopyridine was used
as starting material.
[0040] Pyridine-containing structures may be similarly
synthesized.
[0041] Platinum(II) complexes were prepared from HL.sup.1-HL.sup.11
as described below.
[0042] Acetic acid (3 mL) and water (0.3 mL) were added to a
mixture of the ligand HL.sup.n (e.g., 1.0 mmol) and
K.sub.2PtCl.sub.4 (1 equiv) in a glass vessel with a magnetic stir
bar. The vessel was capped, and then the mixture was heated under
microwave irradiation for 30-60 minutes. Upon cooling to room
temperature, a yellow or yellow-orange precipitate was formed. The
precipitate was separated off from the yellow solution, washed
sequentially with methanol, water, ethanol, and diethyl ether
(e.g., 3.times.5 mL of each), and dried under vacuum.
[0043] Platinum (II) Ligand chloride (PtL.sup.1-11Cl) were treated
with phenol and potassium hydroxide in acetone to give
PtL.sup.1-11OPh for 2-3 hs after being filtrated, washed by water,
acetone, and ether.
[0044] FIG. 3 shows platinum(II) di(2-pyrazolyl)benzene chloride
and analogs synthesized from the ligands. .sup.1H NMR data for
these compounds in DMSO or CDCl.sub.3 are listed below.
[0045] PtL.sup.1Cl: .sup.1H NMR (DMSO): 6.84 (dd, 2H), 7.37 (t,
1H), 7.48 (d, 2H), 7.93 (d, 2H), 8.91 (d, 2H).
[0046] PtL.sup.2Cl: .sup.1H NMR (DMSO): 2.62 (s, 6H), 2.72 (s, 6H),
6.32 (s, 2H), 7.19-7.20 (m, 3H).
[0047] PtL.sup.3Cl: .sup.1H NMR (CDCl.sub.3): 7.40 (dd, 2H), 7.28
(d, 2H), 7.13 (t, 1H), 6.93 (d, 2H).
[0048] PtL.sup.5Cl: .sup.1H NMR (DMSO): 7.28 (t, 1H), 7.95 (d, 2H),
8.14 (d, 2H).
[0049] PtL.sup.8Cl: .sup.1H NMR (CDCl.sub.3): 2.65 (s, 6H), 2.76
(s, 6H), 6.34 (s, 2H), 7.09 (s, 2H).
[0050] PtL.sup.9Cl: .sup.1H NMR (CDCl.sub.3): 7.37 (dd, 2H), 7.11
(d, 2H), 6.91 (d, 2H), 4.04 (s, 6H), 2.34 (s, 3H).
[0051] PtL.sup.2Cl: .sup.1H NMR (CDCl.sub.3): .delta.2.78 (s, 6H),
2.79 (s, 6H), 6.11 (s, 2H), 8.27 (s, 2H).
[0052] PtL.sup.2OPh: .sup.1H NMR (CDCl.sub.3): 7.07-7.16 (m, 5H),
7.02 (d, 2H), 6.49 (t, 1h), 6.01 (s, 2H), 2.71 (s, 6H), 2.45 (s,
6H).
[0053] PtL.sup.2OPhBu-t: .sup.1H NMR (CDCl.sub.3): 7.13 (t, 1H),
7.08 (d, 2H), 7.02 (d, 2H), 7.00 (d, 2H), 6.00 (s, 2H), 2.71 (s,
6H), 2.47 (s, 6H), 1.25 (s, 9H).
[0054] PtL.sup.3OPh: .sup.1H NMR (CDCl.sub.3): 7.23 (d, 2H), 7.17
(d, 2H), 7.11 (t, 1H), 7.06 (t, 1H), 6.85-6.87 (m, 4H), 6.78 (d,
2H), 3.99 (s, 6H).
[0055] FIGS. 4-12 show photoluminescence spectra for several Pt
complexes including PtL.sup.1Cl, PtL.sup.2Cl, PtL.sup.3Cl,
PtL.sup.5Cl, PtL.sup.8Cl, PtL.sup.9Cl, PtL.sup.11Cl and
PtL.sup.2OPh.
[0056] FIG. 4 shows a room temperature emission spectrum of
platinum(II) di(2-pyrazolyl)benzene chloride in
dichloromethane.
[0057] FIG. 5 shows room temperature (plot 500) and 77K (plot 502)
emission spectra of platinum(II)
di(3,5-dimethyl-2-pyrazolyl)benzene chloride in solution.
[0058] FIG. 6 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)benzene chloride in thin
film of poly(methyl methacrylate) (PMMA).
[0059] FIG. 7 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)benzene phenoxide in a
thin film of poly(carbonate).
[0060] FIG. 8 shows a room temperature emission spectrum of
platinum(II) di(3,5-dimethyl-2-pyrazolyl)toluene chloride in a thin
film of poly(methyl methacrylate) (PMMA).
[0061] FIG. 9 shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)benzene chloride in a solution of
dichloromethane.
[0062] FIG. 10 shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)benzene chloride in a thin film
of poly(methyl methacrylate) (PMMA).
[0063] FIG. 11A shows a room temperature emission spectrum of
platinum(II) di(methyl-imidazolyl)toluene chloride in a thin film
of poly(methyl methacrylate) (PMMA).
[0064] FIG. 11B shows a 77K emission spectrum of platinum(II)
di(methyl-imidazolyl)pyridine chloride in a solution of
2-methyl-tetrahydrofuran.
[0065] FIG. 12 shows a room temperature emission spectrum of
platinum(II) di(thiazolyl)(4,6-difluoro-benzene) chloride in a
solution of dichloromethane.
[0066] As seen in these spectra, these complexes provide the
capability of tuning the emission energy of platinum(II) complexes
over a range between ultraviolet and near-infrared, as well as
improved emission in the blue wavelength range. These complexes can
be used as luminescent labels, emitters for OLEDs, and other
applications that benefit from efficient blue emission and high
stability (longer lifetime).
[0067] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention.
* * * * *