U.S. patent application number 14/082061 was filed with the patent office on 2014-04-03 for imidazolidine-based metal carbene metathesis catalysts.
This patent application is currently assigned to CALIFORNIA INSTITUTE OF TECHNOLOGY. The applicant listed for this patent is CALIFORNIA INSTITUTE OF TECHNOLOGY. Invention is credited to Robert H. Grubbs, Matthias Scholl.
Application Number | 20140094612 14/082061 |
Document ID | / |
Family ID | 39031453 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140094612 |
Kind Code |
A1 |
Grubbs; Robert H. ; et
al. |
April 3, 2014 |
IMIDAZOLIDINE-BASED METAL CARBENE METATHESIS CATALYSTS
Abstract
The present invention relates to novel metathesis catalysts with
an imidazolidine-based ligand and to methods for making and using
the same. The inventive catalysts are ##STR00001## wherein: M is
ruthenium or osmium; X and X.sup.1 are each independently an
anionic ligand; L is a neutral electron donor ligand; and, R,
R.sup.1R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each
independently hydrogen or a substituent selected for the group
consisting of C.sub.1-C.sub.20 alkyl, C.sub.2-C.sub.20 alkenyl,
C.sub.2-C.sub.20 alkynyl, aryl, C.sub.1-C.sub.20 alkoxycarbonyl,
C.sub.1-C.sub.20 alkylthiol, aryl thiol, C.sub.1-C.sub.20
alkylsulfonyl and C.sub.1-C.sub.20 alkylsulfinyl, the substituted
optionally substituted with one or more moieties selected from the
group consisting of C.sub.1-C.sub.20 alkyl, C.sub.1-C.sub.10
alkoxy, aryl, and a functional group. The inclusion of an
imidazolidine ligand to the previously described ruthenium or
osmium catalysts has been found to dramatically improve the
properties of these complexes.
Inventors: |
Grubbs; Robert H.; (South
Pasadena, CA) ; Scholl; Matthias; (Arcadia,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CALIFORNIA INSTITUTE OF TECHNOLOGY |
Pasadena |
CA |
US |
|
|
Assignee: |
CALIFORNIA INSTITUTE OF
TECHNOLOGY
Pasadena
CA
|
Family ID: |
39031453 |
Appl. No.: |
14/082061 |
Filed: |
November 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13494708 |
Jun 12, 2012 |
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14082061 |
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12016482 |
Jan 18, 2008 |
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13494708 |
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09576370 |
May 22, 2000 |
7329758 |
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12016482 |
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Current U.S.
Class: |
548/103 |
Current CPC
Class: |
B01J 2531/825 20130101;
B01J 2231/543 20130101; B01J 31/2295 20130101; B01J 2531/821
20130101; C08G 61/08 20130101; B01J 31/2273 20130101; B01J 31/2278
20130101; C07F 15/0046 20130101 |
Class at
Publication: |
548/103 |
International
Class: |
B01J 31/22 20060101
B01J031/22; C07F 15/00 20060101 C07F015/00 |
Goverment Interests
[0002] The U.S. Government has certain rights in this invention
pursuant to Grant No. GM 31332 awarded by the National Institute of
Health.
Claims
1. A compound of the formula ##STR00052## wherein: M is ruthenium
or osmium; X and X.sup.1 are each independently an anionic ligand;
L is a neutral electron donor ligand; and, R, R.sup.1, R.sup.6,
R.sup.7, R.sup.8, and R.sup.9 are each independently hydrogen or a
substituent selected from the group consisting of C.sub.1-C.sub.20
alkyl, C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, aryl,
C.sub.1-C.sub.20 carboxylate, C.sub.1-C.sub.20 alkoxy,
C.sub.2-C.sub.20 alkenyloxy, C.sub.2-C.sub.20 alkynyloxy, aryloxy,
C.sub.2-C.sub.20 alkoxycarbonyl, C.sub.1-C.sub.20 alkylthiol, aryl
thiol, C.sub.1-C.sub.20 alkylsulfonyl and C.sub.1-C.sub.20
alkylsulfinyl, the substituent optionally substituted with one or
more moieties selected from the group consisting of
C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, aryl, and a
functional group selected from the group consisting of hydroxyl,
thiol, thioether, ketone, aldehyde, ester, ether, amine, imine,
amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, carbamate, and halogen.
2. A composition of matter comprising a compound having the
formula: ##STR00053## where: M is Ru or Os; X and X.sup.1 are each
independently an anionic ligand; P is phosphorus; R.sup.g, R.sup.h
and R.sup.i are each independently: (1) a C.sub.1-10 alkyl group,
(2) a C.sub.3-10 cycloalkyl group or (3) a C.sub.5-20 aryl group;
R, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each independently:
(1) hydrogen, (2) a C.sub.1-10 alkyl group, (3) a C.sub.7-20
alkenyl group, (4) a C.sub.2-20 alkynyl group, (5) an aryl group,
(6) a C.sub.1-20 carboxylate group, (7) a C.sub.1-20 alkoxy group,
(8) a C.sub.2-.sub.70 alkenyloxy group, (9) a C.sub.2-20 alkynyloxy
group, (10) an aryloxy group, (11) a C.sub.2-20 alkoxycarbonyl
group, (12) a C.sub.1-20 alkylthiol group, (13) a C.sub.1-20
alkylsulfonyl group, (14) a C.sub.1-20 alkylsulfinyl group, where
each of R, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 is optionally
substituted with (a) halogen, (b) a C.sub.1-10 alkyl group, (c) a
C.sub.1-10 alkoxy group, (d) an aryl group (e) a hydroxyl group,
(f) a thiol group, (g) a thioester group, (h) a ketone group, (i)
an aldehyde group, (j) an ester group, (k) an ether group, (l) an
amino group, (m) an amido group, (n) an imino group, (o) a nitro
group, (p) a carboxylic acid group, (q) a disulfide group, (r) a
carbonate group, (s) an isocyanate group, (t) a carbodiimide group,
(u) a carboalkoxy group, or (v) a carbamate group.
3. An olefin metathesis catalyst wherein the metathesis catalyst
has the following structure: ##STR00054## wherein, M is ruthenium
or osmium: X and X.sup.1 are each independently an anionic ligand;
L.sup.1 is an imidazolidine ligand; L is a neutral electron donor
ligand; and R and R.sup.1 are each independently hydrogen,
C.sub.1-10 alkyl, C.sub.2-20 alkenyl, C.sub.2-20 alkynyl, aryl,
C.sub.1-20 carboxylate, C.sub.1-20 alkoxy, C.sub.2-20 alkenyloxy,
C.sub.2-20 alkynyloxy, aryloxy, C.sub.2-20 alkoxycarbonyl,
C.sub.1-20 alkylthiol, aryl thiol, C.sub.1-20 alkylsulfonyl, and
C.sub.1-20 alkylsulfinyl, and wherein each of R and R.sup.1 is
optionally substituted with halogen. C.sub.1-10 alkyl, C.sub.1-10
alkoxy, aryl, hydroxyl, thiol, thioether, ketone, aldehyde, ester,
ether, amino, amido, imino, nitro, carboxylic acid, disulfide,
carbonate, isocyanate, carbodiimide, carboalkoxy, or carbamate.
4. The metathesis catalyst of claim 3, wherein the imidazolidine
ligand has the following structure: ##STR00055## wherein, R.sup.6,
R.sup.7, R.sup.8, and R.sup.9 are each independently hydrogen,
C.sub.1-10 alkyl, C.sub.2-20 alkenyl, C.sub.2-20 alkynyl, aryl,
C.sub.1-20 carboxylate, C.sub.1-20 alkoxy, C.sub.2-20 alkenyloxy,
C.sub.2-20 alkynyloxy, aryloxy, C.sub.2-20 alkoxycarbonyl,
C.sub.1-20 alkylthiol, aryl thiol, C.sub.1-20 alkylsulfonyl, and
C.sub.1-20 alkylsulfinyl, and wherein each of R.sup.6, R.sup.7,
R.sup.8, and R.sup.9 is optionally substituted with halogen,
C.sub.1-10 alkyl, C.sub.1-10 alkoxy, aryl, hydroxyl, thiol,
thioether, ketone, aldehyde, ester, ether, amino, amido, imino,
nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, or carbamate.
5. The metathesis catalyst of claim 3, wherein at least one of L,
L.sup.1, R, R.sup.1, X, and X.sup.1 may be linked with at least one
of L, L.sup.1, R, R.sup.1, X, and X.sup.1 to form a bonded ligand
array.
6. The metathesis catalyst of claim 3, wherein L may be bonded
together with one of X and X.sup.1 to form a bidentate ligand.
7. The metathesis catalyst of claim 3, wherein L may be bonded
together with one of R and R.sup.1 to form a bidentate ligand.
8. The metathesis catalyst of claim 3, wherein R and R.sup.1 may be
bonded together.
9. The metathesis catalyst of claim 3, wherein the metathesis
catalyst has the following structure: ##STR00056## wherein, M is
ruthenium or osmium; X and X.sup.1 are each independently an
anionic ligand; L is a neutral electron donor ligand; and R,
R.sup.1, R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each
independently hydrogen, C.sub.1-10 alkyl, C.sub.2-20 alkenyl,
C.sub.2-20 alkynyl, aryl, C.sub.1-20 carboxylate, C.sub.1-20
alkoxy, C.sub.2-20 alkenyloxy, C.sub.2-20 alkynyloxy, aryloxy,
C.sub.2-20 alkoxycarbonyl, C.sub.1-20 alkylthiol, aryl thiol,
C.sub.1-20 alkylsulfonyl, and C.sub.1-20 alkylsulfinyl, and wherein
each of R and R.sup.1 is optionally substituted with halogen,
C.sub.1-10 alkyl, C.sub.1-10 alkoxy, aryl, hydroxyl, thiol,
thioether, ketone, aldehyde, ester, ether, amino, amido, imino,
nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, or carbamate.
10. The metathesis catalyst of claim 9, wherein at least one of L,
L.sup.1, R, R.sup.1, R.sup.8, R.sup.9, X, and X.sup.1 may be linked
with at least one of L, L.sup.1, R, R.sup.1, R.sup.8, R.sup.9, X,
and X.sup.1 to form a bonded, bidentate, or multidentate ligand
array.
11. The metathesis catalyst of claim 9, wherein L may be bonded
together with one of X and X.sup.1 to form a bidentate ligand.
12. The metathesis catalyst of claim herein L may be bonded
together with one of R and R.sup.1 to form a bidentate ligand.
13. The metathesis catalyst of claim 9, wherein R and R.sup.1 may
be bonded together.
14. The metathesis catalyst of claim 3, wherein the metathesis
catalyst has the following structure: ##STR00057## wherein, M is Ru
or Os; X and X.sup.1 are each independently an anionic ligand; P is
phosphorus; R.sup.g, R.sup.h and R.sup.i are each independently:
(1) a C.sub.1-10 alkyl group, (2) a C.sub.3-10 cycloalkyl group or
(3) a C.sub.5-20 aryl group; R, R.sup.6, R.sup.7, R.sup.8, and
R.sup.9 are each independently: (1) hydrogen, (2) a C.sub.1-10
alkyl group, (3) a C.sub.2-20 alkenyl group, (4) a C.sub.2-20
alkynyl group, (5) an aryl group, (6) a C.sub.1-20 carboxylate
group, (7) a C.sub.1-20 alkoxy group, (8) a C.sub.2-20 alkenyloxy
group, (9) a C.sub.2-20 alkynyloxy group, (10) an aryloxy group,
(11) a C.sub.2-20 alkoxycarbonyl group, (12) a C.sub.1-20
alkylthiol group, (13) a C.sub.1-20 m alkylsulfonyl group, (14) a
C.sub.1-20 alkylsulfinyl group, where each of R, R.sup.6, R.sup.7,
R.sup.8, and R.sup.9 is optionally substituted with (a) halogen,
(b) a C.sub.1-10 alkyl group, (c) a C.sub.1-10 alkoxy group, (d) an
aryl group (e) a hydroxyl group, (f) a thiol group, (g) a thioester
group, (h) a ketone group, (i) an aldehyde group, (j) an ester
group, (k) an ether group. (l) an amino group, (m) an amino group,
(n) an imino group, (o) a nitro group, (p) a carboxylic acid group,
(q) a disulfide group, (r) a carbonate group, (s) an isocyanate
group, (t) a carbodiimide group, (u) a carboalkoxy group, or (v) a
carbamate group.
Description
[0001] The present invention claims the benefit of U.S. Provisional
Application No. 60/135,493, field on May 24, 1999 by investors
Robert H. Grubbs and Matthias Scholl entitles SYNTHESIS OF
RUTHENIUM-BASED OLEFIN METATHESIS CATALYSTS COORDINATED WITH
1,-3-DISUBSTITUTED-4,5-DIHYDRO-(4,5-DI-SUBSTITUTED)-IMIDAZOXLE-2-YLIDENE
LIGANDS [Attorney Docket No. 20072-0254089 (CIT-2993)] and U.S.
Provisional Application No. 60/142,853, filed Jul. 7, 1999 by
inventors Robert H. Grubbs and Matthias Scholl entitled
IMIDAZOLIDINE-BASED METAL CARBENE METHATHESIS CATALYSTS [Attorney
Docket No. 20072-0254129 (CIT 3021)] which are incorporated herein
by reference in their entireties.
BACKGROUND
[0003] Metathesis catalysts have been previously described by for
example, U.S. Pat. Nos. 5,312,940, 5,342,909, 5,728,917, 5,750,815,
5,710,298, and 5,831,108 and PCT Publications WO 97/20865 and WO
97/29135 which are all incorporated herein by reference. These
publications describe well-defined single component ruthenium or
osmium catalysts that possess several advantageous properties. For
example, these catalysts are tolerant to a variety of functional
groups and generally are more active than previously known
metathesis catalysts. In an unexpected and surprising result, the
inclusion of an imidazolidine ligand in these metal-carbene
complexes has been found to dramatically improve the already
advantageous properties of these catalysts. For example, the
imidazolidine-based catalysts of the present invention exhibit
increased activity and selectivity not only in ring closing
metathesis ("RCM") reactions, but also in other metathesis
reactions including cross metathesis ("CM") reactions, reactions of
acyclic olefins, and ring opening metathesis polymerization
("ROMP") reactions.
SUMMARY
[0004] The present invention relates to novel metathesis catalysts
with an imidazolidine-based ligand and to methods for making and
using the same. The inventive catalysts are of the formula
##STR00002##
wherein: [0005] M is ruthenium or osmium; [0006] X and X.sup.1 are
each independently an anionic ligand; [0007] L is a neutral
electron donor ligand; and [0008] R, R.sup.1R.sup.6, R.sup.7,
R.sup.8, and R.sup.9 are each independently hydrogen or a
substituent selected from the group consisting of C.sub.1-C.sub.20
alkyl, C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, aryl,
C.sub.1-C.sub.20 carboxylate, C.sub.1-C.sub.20 alkoxy,
C.sub.2-C.sub.20 alkenyloxy, C.sub.2-C.sub.20 alkynyloxy, aryloxy,
C.sub.2-C.sub.20 alkoxycarbonyl, C.sub.1-C.sub.20 alkylthiol, aryl
thiol, C.sub.1-C.sub.20 alkylsulfonyl and C.sub.1-C.sub.20
alkylsulfinyl. Optionally, each of the R, R.sup.1R.sup.6, R.sup.7,
R.sup.8, and R.sup.9 substituent group may be substituted with one
or more moieties selected from the group consisting of
C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, and aryl which in
turn may each be further substituted with one or more groups
selected from a halogen, a C.sub.1-C.sub.5 alkyl, C.sub.1-C.sub.5
alkoxy, and phenyl. Moreover, any of the catalyst ligands may
further include one or more functional groups. Examples of suitable
functional groups include but are not limited to: hydroxyl, thiol,
thioether, ketone, aldehyde, ester, ether, amine, imine, amide,
nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, carbamate, and halogen. The inclusion of
an imidazolidine ligand to the previously described ruthenium or
osmium catalysts has been found to dramatically improve the
properties of these complexes. Imidazolidine ligands are also
referred to as 4,5-dihydro-imidazole-2-ylidene ligands. Because the
imidazolidine-based complexes are extremely active, the amount of
catalysts that is required is significantly reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 compares the ROMP activity of COD of representative
catalysts of the present invention with previously described
metathesis catalysts as determined by .sup.1H NMR spectroscopy. The
reactions were performed at 20.degree. C. with CD.sub.2Cl.sub.2 as
solvent, a monomer/catalyst ration of 300, and a catalyst
concentration of 0.5 mM.
[0010] FIG. 2 compares the ROMP activity of COE of representative
catalysts of the present invention with previously described
metathesis catalysts as determined by .sup.1H NMR spectroscopy. The
reactions were performed at 20.degree. C. with CD.sub.2Cl.sub.2 as
solvent, a monomer/catalyst ratio 300, and a catalyst concentration
of 0.5 mM.
[0011] FIG. 3 compares the ROMP activity of COD at an elevated
temperature of representative catalysts of the present invention
with previously described metathesis catalysts as determined by
.sup.1H NMR spectroscopy. The reaction were performed at 55.degree.
C. with CD.sub.2Cl.sub.2 as solvent, a monomer/catalyst ratio of
300, and a catalyst concentration of 0.5 mM.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The present invention generally relates to ruthenium and
osmium carbene catalyst for use in olefin metathesis reactions.
More particularly, the present invention relates to
imidazolidine-based ruthenium and osmium carbene catalysts and to
methods for making and using the same. The terms "catalyst" and
"complex" herein are used interchangeably.
[0013] Unmodified ruthenium and osmium carbene complexes have been
described in U.S. Pat. Nos. 5,312,940, 5,342,909, 5,728,917,
5,750,815, and 5,710,298, all of which are incorporated herein by
reference. The ruthenium and osmium carbene complexes disclosed in
these patients all possess metal centers that are formally in the
+2 oxidation state, have an electron count of 16, and are
penta-coordinated. These catalysts are of the general formula
##STR00003##
wherein: [0014] M is ruthenium or osmium; [0015] X and X.sup.1 are
each independently any anionic ligand; [0016] L and L.sup.1 are
each independently any neutral electron donor ligand; [0017] R and
R.sup.1 are each independently hydrogen or a substituent selected
from the group consisting of C.sub.1-C.sub.20 alkyl,
C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, aryl,
C.sub.1-C.sub.20 carboxylate, C.sub.1-C.sub.20 alkoxy,
C.sub.2-C.sub.20 alkenyloxy, C.sub.2-C.sub.20 alkynyloxy, aryloxy,
C.sub.2-C.sub.20 alkoxycarbonyl, C.sub.1-C.sub.20 alkylthiol, aryl
thiol, C.sub.1-C.sub.20 alkylsulfonyl and C.sub.1-C.sub.20
alkylsulfinyl. Optionally, each of the R or R.sup.1 substituent
group may be substituted with one or more moieties selected from
the group consisting of C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10
alkoxy, and aryl which in turn may each be further substituted with
one or more groups selected from a halogen, a C.sub.1-C.sub.5
alkyl, C.sub.1-C.sub.5 alkoxy, and phenyl. Moreover, any of the
catalyst ligands may further include one or more functional groups.
Examples of suitable functional groups include but are not limited
to: hydroxyl, thiol, thioether, ketone, aldehyde, ester, ether,
amine, imine, amide, nitro, carboxylic acid, disulfide, carbonate,
isocyanate, carbodiimide, carboalkoxy, carbamale, and halogen.
[0018] The catalysts of the present invention are as described
above except that L.sup.1 is an unsubstituted or substituted
imidazolidine,
##STR00004##
resulting in a complex of the general formula
##STR00005##
wherein: [0019] R.sup.6, R.sup.7, R.sup.8, and R.sup.9 are each
independently hydrogen or a substituent selected from the group
consisting of C.sub.1-C.sub.20 alkyl, C.sub.2-C.sub.20 alkenyl,
C.sub.2-C.sub.20 alkynyl, aryl, C.sub.1-C.sub.20 carboxylate,
C.sub.1-C.sub.20 alkoxy, C.sub.2-C.sub.20 alkenyloxy,
C.sub.2-C.sub.20 alkynyloxy, aryloxy, C.sub.2-C.sub.20
alkoxycarbonyl, C.sub.1-C.sub.20 alkylthiol, aryl thiol,
C.sub.1-C.sub.20 alkylsulfonyl and C.sub.1-C.sub.20 alkylsulfinyl.
Imidazolidine ligands are also referred to as
4,5-dihydro-imidazole-2-ylidene ligands.
[0020] In preferred embodiments of the inventive catalysts, the R
substituent is hydrogen and the R.sup.1 substituent is selected
from the group consisting of C.sub.1-C.sub.20 alkyl,
C.sub.2-C.sub.20 alkenyl, and aryl. In even more preferred
embodiments, the R.sup.1 substituent is phenyl or vinyl, optionally
substituted with one or more moieties selected from the group
consisting of C.sub.1-C.sub.5 alkyl, C.sub.1-C.sub.5 alkoxy,
phenyl, or vinyl substituted with one ore more moieties selected
from the group consisting of chloride, bromide, iodide, fluoride,
--NO.sub.2, --NMe.sub.2, methyl, methoxy and phenyl. In the most
preferred embodiments, the R.sup.1 substituent is phenyl or
--C.dbd.C(CH.sub.3).sub.2.
[0021] In preferred embodiments of the inventive catalysts, L is
selected from the group consisting of phosphine, sulfonated
phosphine, phosphite, phosphinite, phosphonite, arsine, stibine,
ether, amine, amide, imine, sulfoxide, carboxyl, nitrosyl,
pyridine, and thioether. In more preferred embodiments, L is a
phosphine of the formula PR.sup.3R.sup.4R.sup.5, where R.sup.3,
R.sup.4, and R.sup.5 are each independently aryl or
C.sub.1-C.sub.10 alkyl, particularly primary alkyl, secondary alkyl
or cycloalkyl. In the most preferred embodiment, L is each selected
from the group consisting of --P(cyclohexyl).sub.3,
--P(cyclopentyl), --P(isopropyl), and --P(phenyl).sub.3.
[0022] In preferred embodiments of the inventive catalysts, X and
X.sup.1 are each independently hydrogen, halide, or one of the
following groups: C.sub.1-C.sub.20 alkyl, aryl, C.sub.1-C.sub.20
alkoxide, aryloxide, C.sub.3-C.sub.20 alkyldiketonate,
aryldiketonate, C.sub.1-C.sub.20 carboxylate, arylsulfonate,
C.sub.1-C.sub.20 alkylsulfonate, C.sub.1-C.sub.20 alkylthiol, aryl
thiol, C.sub.1-C.sub.20 alkylsulfonyl, or C.sub.1-C.sub.20
alkylsulfinyl. Optionally, X and X.sup.1 may be substituted with
one or more moieties selected from the group consisting of
C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, and aryl which in
turn may each be further substituted with one or more groups
selected from halogen, C.sub.1-C.sub.5 alkyl, C.sub.1-C.sub.5
alkoxy, and phenyl. In more preferred embodiment, X and X.sup.1 are
halide, benzoate, C.sub.1-C.sub.5 carboxylate, C.sub.1-C.sub.5
alkyl, phenoxy, C.sub.1-C.sub.5 alkoxy, C.sub.1-C.sub.5 alkylthiol,
aryl thiol, aryl, and C.sub.1-C.sub.5 alkyl sulfonate. In even more
preferred embodiments, X and X.sup.1 are each halide,
CF.sub.3CO.sub.2, CH.sub.3CO.sub.2, CFH.sub.3CO.sub.2,
(CH.sub.3).sub.3CO, (CF.sub.3).sub.2(CH.sub.3).sub.2(CH.sub.3)CO,
(CF.sub.3)(CH.sub.3).sub.2CO, PhO, MeO, EtO, tosylate, mesylate, or
trifluoromethanesulfonate. In the more preferred embodiments, X and
X.sup.1 are each chloride.
[0023] In preferred embodiments of the inventive catalysts, R.sup.6
and R.sup.7 are each independently hydrogen, phenyl, or together
form a cycloalkyl or an aryl optionally substituted with one or
more moieties selected from the group consisting of
C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, aryl, and a
functional group selected from the group consisting of hydroxyl,
thiol, thioether, ketone, aldehyde, ester, ether, amine, imine,
amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, carbamate, and halogen; and R.sup.8 and
R.sup.9 are each is independently C.sub.1-C.sub.10 alkyl or aryl
optionally substituted with C.sub.1-C.sub.5 alkyl, C.sub.1-C.sub.5
alkoxy, aryl, and a functional group selected from the group
consisting of hydroxyl, thiol, thioether, ketone, aldehyde, ester,
ether, amine, imine, amide, nitro, carboxylic acid, disulfide,
carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and
halogen.
[0024] In more preferred embodiments, R.sup.6 and R.sup.7 are both
hydrogen or phenyl, or R.sup.6 and R.sup.7 together form a
cycloalkyl group; and R.sup.8 and R.sup.9 are each either
substituted or unsubstituted aryl. Without being bound by theory,
it is believed that bulkier R.sup.8 and R.sup.9 groups result in
catalysts with improved characteristics such as thermal stability.
In especially preferred embodiments, R.sup.8 and R.sup.9 are the
same and each is independently of the formula
##STR00006##
wherein: [0025] R.sup.10, R.sup.11, and R.sup.12 are each
independently hydrogen, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10
alkoxy, aryl, or a functional group selected from hydroxyl, thiol,
thioether, ketone, aldehyde, ester, ether, amine, imine, amide,
nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, carbamate, and halogen. In especially
preferred embodiments, R.sup.10, R.sup.11, and R.sup.12 are each
independently selected from the group consisting of hydrogen,
methyl, ethyl, propyl, isopropyl, hydroyxl, and halogen. In the
most preferred embodiments, R.sup.10, R.sup.11, and R.sup.12 are
the same and are each methyl.
[0026] Examples of the most preferred embodiments of the present
invention include:
##STR00007##
wherein Mcs is
##STR00008##
(also known as "mesityl"); i-Pr is isopropyl; and PCy.sub.3 is
--P(cyclohexyl).sub.3.
Synthesis
[0027] In general, the catalysts of the present invention are made
by contacting an imidazolidine with a previously described
ruthenium/osmium catalyst
##STR00009##
whereby the imidazolidine replaces one of the L ligands. The
imidazolidine may be made using any suitable method.
[0028] In preferred embodiments, the method for making the
inventive catalysts comprises contacting an imidazolidine of the
general formula
##STR00010##
wherein: [0029] M is ruthenium or osmium; [0030] X and X.sup.1 are
each independently an anionic ligand; [0031] L is a neutral
electron donor ligand; [0032] R, R.sup.1R.sup.6, R.sup.7, R.sup.8,
and R.sup.9 are each independently hydrogen or a substituted
selected from the group consisting of C.sub.1-C.sub.20 alkyl,
C.sub.2-C.sub.20 alkenyl, C.sub.2-C.sub.20 alkynyl, aryl,
C.sub.1-C.sub.20 carboxylate, C.sub.1-C.sub.20 alkoxy,
C.sub.2-C.sub.20 alkenyloxy, C.sub.2-C.sub.20 alkynyloxy, aryloxy,
C.sub.2-C.sub.20 alkoxycarbonyl, C.sub.1-C.sub.20 alkylthiol, aryl
thiol, C.sub.1-C.sub.20 alkylsulfonyl and C.sub.1-C.sub.20
alkylsulfinyl, the substituent optionally substituted with one or
more moieties selected from the group consisting of
C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, aryl, and a
functional group selected from the group consisting of hydroxyl,
thiol, thioether, ketone, aldehyde, ester, ether, amine, imine,
amide, nitro, carboxylic acid, disulfide, carbonate, isocyanate,
carbodiimide, carboalkoxy, carbamate, and halogen; and, [0033]
R.sup.13 is C.sub.1-C.sub.20 alkyl or aryl.
[0034] If desired, the contacting step may be performed in the
present of heat. Typically, the replacement reaction whereby the
imidazolidine displaces one of the L ligands occurs in about 10
minutes in the presence of heat.
[0035] The imidazolidine may be synthesized by contacting a diamine
with a salt to form an imidazolium salt; and then contacting the
imidazolium salt with a base (preferably an alkyloxide) to make the
imidazolidine in a form suitable for reacting with
##STR00011##
[0036] One embodiment for the synthetic method is as follows.
First, a diketone is contacted with a primary amine (R--NH.sub.2
wherein R.sup.8.dbd.R.sup.9) or amines (R.sup.8--NH.sub.2 and
R.sup.9--NH.sub.2) to form a diimine which is then reduced to form
a diamine.
##STR00012##
[0037] In preferred embodiments, R.sup.8 and R.sup.9 are the same
and are each independently C.sub.1-C.sub.10 alkyl or aryl
optionally substituted with C.sub.1-C.sub.5 alkyl, C.sub.1-C.sub.5
alkoxy, aryl, and a functional group selected from the group
consisting of hydroxyl, thiol, thioether, ketone, aldehyde, ester,
ether, amine, imine, amide, nitro, carboxylic acid, disulfide,
carbonate, isocyanate, carbodiimide, carboalkoxy, carbamate, and
halogen.
[0038] When R.sup.6 and R.sup.7 together form a cycloalkyl and
R.sup.8 and R.sup.9 are the same, the following alternate protocol
may be used to make the diamine intermediate of the present
invention:
##STR00013##
wherein R' represents both R.sup.8 and R.sup.9 since
R.sup.8.dbd.R.sup.9. Because a number of optionally active primary
cycloalkyldiamines are commercially available, this protocol may be
used to synthesize optically active imidazolidine ligands. In
addition, chiral metathesis complexes are also possible.
[0039] The diamine intermediate is used to prepare an imidazolium
salt. In one embodiment, ammonium tetrafluoroborate may be
used.
##STR00014##
[0040] The resulting imidazolium salt is then reacted with a base
to make the imidazolidine.
##STR00015##
[0041] Representative examples of suitable bases include the
t-BuOK/THF and MeONa/MeOH.
[0042] Metathesis Reactions
[0043] The catalysts of the present invention may be used for any
metathesis reaction (i.e. ring opening metathesis polymerization,
ring closing metathesis, cross metathesis, etc.) by contacting the
inventive catalysts with an appropriate olefin. Any olefin may be
used and as used herein an olefin is a substituted or unsubstituted
alkene and is any compound including cyclic compounds that possess
a carbon-carbon double bond. Unlike previously described metathesis
catalysts, the inventive complexes can initiate reactions involving
even highly substituted olefins such as tri and tetra substituted
olefins (e.g., R.sup.1R.sup.2C.dbd.CR.sup.3R.sup.4 wherein R.sup.1,
R.sup.2, R.sup.3, and R.sup.4 are independently each a hydrogen or
a non-hydrogen moiety) and olefins bearing electron withdrawing
groups.
[0044] In general, the method for performing a metathesis reaction
comprises contacting a suitable olefin with a catalyst of the
present invention. To date, the most widely used catalysts for ROMP
and other metathesis reactions are
##STR00016##
wherein PCy.sub.3 is --P(cyclohexyl).sub.3 and Ar is
C.sub.6H.sub.3-2,6-(PR). The molybdenum catalyst 8 displays much
higher activity than the ruthenium catalyst 7, thus permitting
polymerization of many sterically hindered or electronically
deactivated cyclic olefins. However, the ruthenium catalyst 7 is
stable under ambient conditions and tolerates a much larger range
of protic and polar functional groups such as alcohols, acids and
aldehydes. The catalysts of the present invention combine the best
features of both complexes 7 and 8. In particular, the inventive
imidazolidine catalysts rival and often exceed the activity of
molybdenum complex 8 while maintaining the stability and functional
group compatibility of ruthenium complex.
[0045] The exchanged properties of the inventive catalysts are
illustrated by a series of experiments. For example, Table 1
contains representative results comparing the activities of two
representative catalysts (1 and 2) of the present invention with
complex 7 in several ring closing metathesis reactions with an
acyclic olefin.
TABLE-US-00001 TABLE 1 Results of the RCM with 5 mol % cat. in
0.05M CH.sub.2Cl.sub.2 at reflux % Yield % Yield % Yield (Time,
min) (Time, min) (Time, min) Entry Substrate Product with catalyst
7 with catalyst 1 with catalyst 2.sup.a 1 ##STR00017## ##STR00018##
100 (<30) 100 (5) 100 (8) 2 ##STR00019## ##STR00020## 25 (12) 82
(30) 100 (8) 100 (12) 3 ##STR00021## ##STR00022## N.R. (50) 100
(60) 65 (20) 92 (12 hrs) 4 ##STR00023## ##STR00024## N.R. (90) N.R.
14 (100) 47 (36 hrs) 5 ##STR00025## ##STR00026## N.R. (90) 90 (90)
80 (60) 92 (12 hrs) 6 ##STR00027## ##STR00028## 39.sup.b (60)
35.sup.c (60) 55.sup.c (60) E = CO.sub.2Et; .sup.ain
CD.sub.2Cl.sub.2, conversion determined by 1H NMR, .sup.bE:Z =
1.6:1, .sup.cE:Z = 2.0:1
[0046] As it can be seen, the ring closure of diethyl
diallylmalonate ester (entry 1) is completed in less than 10
minutes at 40.degree. C. with both complexes 1 and 2 while complex
7 requires about 30 minutes. The increased activity of complexes 1
and 2 i most apparent in RCM reactions with more sterically
demanding olefins. For example, 2-tert-butyl-diethyl diallyl
malonate ester (entry 3) can be cyclized with 5 mol % of catalyst 1
in one hour, with 5 mol % of catalyst 2 in twelve hours, while the
corresponding reaction with 5 mol % of catalyst 7 does not yield
any significant amount of cyclized product. Similarly,
tetrasubstituted olefins (entries 4 and 5) can be prepared in
moderate to excellent yields using complexes 1 and 2.
[0047] Table 2 shows the results of the same RCM experiments for
previously described metathesis catalysts including complexes 7 and
8.
TABLE-US-00002 TABLE 2 RCM ACTIVITY COMPARISONS Substrate E = CO
Product ##STR00029## ##STR00030## ##STR00031## ##STR00032##
##STR00033## ##STR00034## -- 30 min 100% 30 min 100% 30 min 100%
##STR00035## ##STR00036## 24 hrs 100% 30 min % 30 min 100% --
##STR00037## ##STR00038## 24 hrs % min 100% 30 min % ##STR00039##
##STR00040## 24 hrs % 90 min 40% 30 min 53% ##STR00041##
##STR00042## 24 hrs % min % 30 min % ##STR00043## ##STR00044## --
min % min % 30 min % indicates data missing or illegible when
filed
[0048] Since complexes 1 and 2 are much more reactive than complex
7, the use of lower catalysts loading for RCM reactions was
investigated. The ring closure of diethyl diallylmalonate under the
reaction conditions listed in Table 1 was conducted using 0.1,
0.05, and 0.01 mol % of catalysts (1 or 2) with respect to the
substrate. In the first case, quantitative conversions within one
hour were observed with both catalysts; in the second case, the
conversion were quantitative with 1 (one hour) and 94% with 2
(three hours). In the third case, the conversions were nearly zero,
which indicates that 0.01 mol % is at the lower limit of the
catalyst loading for this type of RCM reactions.
[0049] The catalysts of the present invention are also useful for
ROMP reactions. In general, the method involves contracting the
catalyst with a cyclic olefin. The cyclic olefin substrate may be a
single cyclic olefin or a combination of cyclic olefins (i.e. a
mixture of two or more different cyclic olefins). The cyclic
olefins may be strained or unstrained, monocyclic or polycyclic,
and may optionally include hereto atoms and/or one or more
functional groups. Suitable cyclic olefins include but are not
limited to norbornene, norbornadiene, dicyclopentadiene,
cyclopentene, cycloheptene, cyclooctene, cyclooctadiene,
cyclododecene, 7-oxanorbornene, 7-oxanorbomadiene, and derivatives
therefrom. Illustrative examples of suitable functional groups
include but are not limited to hydroxyl, thiol, ketone, aldehyde,
ester, ether, amine, imine, amide, nitro, carboxylic acid,
disulfide, carbonate, isocyanate, carbodiimide, carboalkoxy, and
halogen. Preferred cyclic olefins include norbornene and
dicyclopentadiene and their respective homologs and derivatives.
The most preferred cyclic olefin is dicyclopentadiene ("DCPD").
[0050] The ROMP reaction may occur either in the presence of
absence of solvent and may optionally include formulation
auxiliaries. Known auxiliaries include antistatics, antioxidants,
light stabilizers, plasticizers, dyes, pigments, fillers,
reinforcing fibers, lubricants, adhesion promoters,
viscosity-increasing agents and demolding enhancers. Illustrative
examples of fillers for improving the optical physical, mechanical
and electrical properties include glass and quartz in the form of
powders, beads and fibers, metal and semi-metal oxides, carbonates
(i.e. MgCO.sub.3, CaCO.sub.3), dolomite, metal sulfates (such as
gypsum and barite), natural and synthetic silicates (i.e. zeolites,
wollastonite, feldspars), carbon fibers, and plastics fibers or
powders.
[0051] The inventive catalysts' utility in ROMP reactions was
demonstrated with polymerizations both endo- and exo-DCPD. Exposure
of neat DCPD to catalyst 1(10,000:1) yielded within seconds a hard,
highly-crosslinked material. In fact, catalyst loadings as low as
130,000:1 have been used to make high-quality poly-DCPD product. In
contrast, previously described ruthenium and osmium catalysts such
as 7, required loadings of 7,000:1 to obtain similar poly-DCPD
products.
[0052] As demonstrated by the synthesis of telechelic polybutadiene
by chain transfer ROMP, the inventive catalysts are also extremely
active in the polymerization of unstrained cyclic olefins. For
example, with a catalyst loading of about 12,000:1 (monomer to
catalyst 1), the yield of telechelic polymers is higher (65%) than
that using the bis-phosphine complex 7 at much lower monomer to
catalyst ratio of 2,000:1 (50%).
[0053] High activities were also observed in the crossmetathesis of
acyclic olefins. As an example, the cross metathesis of
9-decen-1-yl benzoate with cis-2-buten-1,4-diol diacetate catalyzed
by 2 gave a high yield (80%) and a higher amount of the trans
isomer (E:Z=9:1) compared to that when the corresponding
bis-phosphine complex 7 was used (E:Z=5.7:1).
EXAMPLE 1
[0054] A synthetic protocol for a representative example of an
imidazolidine ligand is as follows. Other imidazolidine ligands are
made analogously.
Preparation of 1,2-dimesityl ethylene diimine
[0055] A 300 mL round bottom flask was charged with acetone (50
mL), water (100 mL) and mesityl amine (10.0 g, 74 mmol). The
solution was cooled to 0.degree. C. and a solution of 40% glyoxal
in water (5.38 g, 37 mmol) was added slowly. The reaction mixture
was allowed to warm up to mom temperature slowly and was stirred
for additional 8 hours. The yellow precipitate formed was filtered
off, briefly washed with cold acetone and air-dried to yield
1,2-dimesityl ethylene diimine.
Preparation of 1,2-dimesityl ethylene diamine
[0056] (a) with H.sub.2, Pd/C: A 50 mL round bottom flask was
charged with 1,2-dimesityl ethylene diimine (300 mg, 1.01 mmol) and
ethanol (20 mL). 10% Pd/C (30 mg) was added and a hydrogen balloon
was attached via a needle. TLC indicated complete spot-to-spot
conversion within 4 hours. The Pd catalyst was filtered off and the
volatiles were pumped off in vacuo to yield 1,2-dimesityl ethylene
diamine.
[0057] (b) with NaCNBH.sub.3: A 300 mL round bottom flask was
charged with 1,2-dimesityl ethylene diimine (3.8 g, 13 mmol),
methanol (100 mL) and NaCNBH.sub.3 (4,92 g, 78 mmol). Concentrated
HCl was added dropwise to maintain the pH below 4, and the reaction
was stirred at room temperature for 20 hours (overnight). The
solution was then diluted with 50 mL water, made basic with NaOH,
and extracted thoroughly with CH.sub.2Cl.sub.2. The organic layer
war dried over MgSO.sub.4, filtered and the solvent was removed in
vacuo to yield 1,2-dimesityl ethylene diamine (95% yield).
Preparation of 1,3-dimesityl-4,5-dihydro-imidazolium
tetrafluoroborate
[0058] A round bottom flask was charged with 1,2-dimesityl ethylene
diamine (3.8 g, 12.8 mmol), triethyl orthoformate (15 mL), and
ammonium tetrafluoroborate (1.35 g, 12.8 mmol). The reaction
mixture was stirred as 120.degree. C. for 4 hours at which time TLC
indicated complete conversion. Volatiles were removed in vacuo and
the product was used as prepared or it could be purified further by
recrystallization from ethanol/hexanes.
EXAMPLE 2
Synthesis of
Cl.sub.2Ru(.dbd.CHPh)(PCy.sub.3)(1,3-dimesityl-4,5-dihydro-2-imidazole)
[0059] The imidazolidine ligand synthesized as detailed in Example
1 is used to prepare the corresponding imidazolidine catalyst
("complex 1") of the present invention. A 100-mL flame dried
Schlenk flask equipped with a magnetic stir bar was charged with
1,3-dimesityl-4,5-dihydro-imidazolium tetrafluoroborate (394 mg,
1.0 mmol, 1 equiv.) and dry THF (20 mL) under nitrogen atmosphere.
To this suspension, potassium tert-butoxide (122 mg, 1.0 mmol, 1
equiv.) was slowly added at room temperature. The tetrafluoroborate
salt was dissolved immediately to give a yellow solution. The
reaction mixture was allowed to stir at room temperature for one
hour, followed by cannula transferring the reaction solution into
another 100-mL dry Schlenk flask under Argon. The solvent was
evaporated under high vacuum, followed by adding dry benzene (25
mL) and RuCl.sub.2(.dbd.CHPh)(PCy.sub.3).sub.2 (700 mg, 0.85
equiv.). The reaction mixture was heated at 80 .degree. C. for 90
minutes. When the reaction was complete indicated by NMR, the
volatiles were removed under high vacuum and the residue was washed
by dry methanol (20 ml.times.4) to give pinkish brown
microcrystalline solid (404 mg) in 56% yield.: .sup.1H NMR
(CD.sub.2Cl.sub.2, 400 MHz) .delta. 19.16 (s, 1H), 7.37-7.05 (m,
9H), 3.88 (s, 4H), 2.56-0.15 (m, 51H); .sup.11P NMR
(CD.sub.2Cl.sub.2, 161.9 MHz) .delta. 31.41; HRMS (FAB)
C.sub.45H.sub.65Cl.sub.2N.sub.2PRu [M.sup.+] 848.3306, found
848.3286.
EXAMPLE 3
Synthesis of Complex 2
[0060] A second example of synthetic protocol for making the
inventive catalysts (complex 2) follows.
1,3-dimesityl-trans-hexahydrobenzoimidazolium tetrafluoroborate
(272 mg, 0.61 mmol, 0.1 equiv.) was suspended in anhydrous
tetrahydrofuran ("THF"; 5 mL) under inert atmosphere. To this
suspension, potassium tert-butoxide ("KO.sup.1Bu") was added (65
mg, 0.61 mmol, 1.0 equiv.). Immediately upon addition of
KO.sup.1Bu, the tetrafluoroborate salt dissolved completely and the
reaction moisture turned yellow. Complex 7,
RuCl.sub.2(.dbd.CHPh)(PCy.sub.3).sub.2 (400 mg, 0.49 mmol), was
added to the reaction mixture as a solution in anhydrous benzene
(15 mL). The reaction mixture was heated in an oil bath at
80.degree. C. for 80 minutes at which time .sup.1H NMR spectrum
indicated a ration of product (complex 2) to complex 7 of 95:5.
Volatiles were removed in vacuo and the residue was washed under
inert atmosphere with anhydrous pentane (4.times.20 mL) to give
pure product as a pinkish-brown microcrystalline solid (270 mg, 0.3
mmol) in 61% yield. Scheme 1 illustrates this protocol for complex
2 as well as for complexes 1 and 3.
##STR00045##
EXAMPLE 4
[0061] The following are representative protocols for several
common metathesis reactions.
[0062] RCM Reactions
[0063] Complex 1 (41 mg, 50 .mu.mol, 0.05 equiv.) was added to a
solution of diheptyl diallymalonate (240 mg, 1 mmol, 1 equiv.) in
methylene chloride (20 mL, 0.05M). The reaction mixture was
refluxed on a oil bath (45.degree. C.) for 5 minutes at which time
.sup.1H NMR indicated 100% conversion to
cyclopent-3-ene-1,1-dicarboxylic acid diethyl ester.
[0064] Cross Metathesis Reactions
[0065] Complex 2 (11 mg, 12 .mu.mol, 0.023 equiv.) was added to a
mixture of 9-decen-1-yl benzoate (145 .mu.L, 0.525 mmol, 1 equiv.)
and cis-2-buten-1,4-diol diacetate (160 .mu.L, 1.014 mmol, 1.93
equiv.) in methylene chloride (2.5 mL, 0.21 M). After refluxing for
3.5 hours, the mixture was purified by flash column chromatography
to yield the cross metathesis product as a clear, colorless oil
(140 mg, 80% yield, E:Z=9:1).
[0066] ROMP Reactions with DCPD:
[0067] Complex 1 (6.5 mg, 7.5 .mu.mol, 1 equiv.) in a small amount
of CH.sub.2Cl.sub.2 (100 .mu.L) was added to a stirring neat
dicyclopentadiene (mixture of exo- and endo-isomers) (10.0 g, 75.6
mmol, 10,000 equiv.). Within a few seconds, the reaction mixture
became increasingly viscous, warmed up significantly, and
solidified shortly theareafter. On cooling, an odor free, nearly
colorless solid was obtained.
[0068] Telechelic Synthesis
[0069] Complex 1 (3.1 mg, 3.7 .mu.mol, 1 equiv.) was added to a
stirring mixture of cyclooctadiene (5.00 g, 4.62 mmol, 12,500
equiv.) and 1,4-dichloro-cis-2-butene (1.16 g, 9.28 mmol, 2,500
equiv.). After 8 hours, the reaction mixture was diluted with
methylene chloride (1 mL) and poured into an excess of methanol
precipitating the dichloro-telechelic polybutadiene as a white
solid (4.0 g, 65% yield).
[0070] Polymerization of 5,6-Dihydroxycycloctene
[0071] In a nitrogen filled drybox, a small vial was charged with 2
mg catalyst (1 equiv.), 150 mg 5,6-dihydroxycycloctene (1000
equiv.), and 0.25 mL of benzene. The vial was capped tightly,
removed from the drybox, and submerged in a constant temperature
oil bath set at 50 degrees. After 10 hours, a slightly yellow
viscous oil formed. Upon the addition of tetrahydrofuran, a white
gel separated and was found to be insoluble in all common organic
solvents. Residual, unreacted monomer could be detected in the
tetrahydrofuran layer by .sup.1H NMR.
EXAMPLE 5
[0072] To better appreciate the advantageous properties of the
inventive catalysts, the ROMP reactions of low strain cyclic
olefins, cis, cis-cycloocta-1,5-diene ("COD") and cis-cyclooctene
("COE") with inventive catalysts 1 and 6
##STR00046##
and representative prior art catalysts
##STR00047##
wherein Ar.dbd.C.sub.6H.sub.3-2,6-(.sup.1PR) ("catalyst 8") and
##STR00048##
wherein R=Mes ("catalyst 9") were compared. The molybdenum catalyst
8 was purchased from Strem Chemicals and recrystallized from
pentane at -40.degree. C. prior to use. For the ROMP kinetics
experiments, COD, COE, and CD.sub.2Cl.sub.2 were distilled from
CaH.sub.2 and bubbled with argon prior to use. All polymerizations
were performed under an atmosphere of nitrogen.
[0073] The ROMP and COD and COE were catalyzed with the respective
catalysts and the percent monomer converted to polymer was followed
over time using .sup.1H NMR spectroscopy. As shown by FIGS. 1 and
2, the rate of polymerization at 20.degree. C. using catalyst 1 was
significantly higher than the molybdenum catalyst 8. As illustrated
by FIG. 3, the rate of polymerization at 55.degree. C. using
catalysts 6 and 9 were also higher than for the molybdenum catalyst
8. Because the propagating species resulting from catalysts 1 and 6
are the same, the observed difference in polymerization rates
between them is believed to be due to the initiation rate. The
bulkier benzylidene is believed to facilitate phosphine
dissociation thereby enhancing initiation to a greater extent than
the dimenthylvinyl carbene counterpart. Previous studies have shown
that alkylidene electronics have a relatively small influence on
the initiation rate.
[0074] Although imidazole-based catalysts such as catalyst 9 and
the imidazoline-based catalyst of the present invention may appear
structurally similar, they possess vastly different chemical
properties due to the differences in their electronic character of
the five membered ring. For example, the chemical differences
between
##STR00049##
and
##STR00050##
is as profound as the differences between
##STR00051##
EXAMPLE 6
[0075] The catalysts of the present invention are capable of
polymerizing a variety of low strain cyclic olefins including
cyclooctadiene, cyclooctene, and several functionalized and
sterically hindered derivatives with extremely low catalyst loading
(up to monomer/catalysts=100,000). Representative results are shown
by Table 3.
TABLE-US-00003 TABLE 3 ROMP of various low strain cyclic olefins
Monomer to Catalyst Temp. Yield % Monomer Ratio (.degree. C.) Time
(%) M.sub.b (PDI).sup.a Trans.sup.b 1,5 cyclooctadiene 100,000 55
30 min 85 112,400 (2.3) 70 10,000 25 24 h 85 92,900 (2.5) 85 25,000
55 24 h 89 10,700 (2.1) 90 cyclooctene 100,000 55 5 min e e f
10,000 25 30 min e e f 25,000.sup.c 55 24 h 75 2200 (1.6) 85
1-hydroxy 4- 100,000 55 5 min e e f cyclooctene 10,000 25 30 min e
e f 25,000.sup.d 55 24 h 85 2600 (2.3) 85 1-acetoxy-4- 10,000 55 5
min 50 103,900 (2.8) 85 cyclooctene 1000 25 1 h 60 79,300 (3.2) 90
5-methylcyclopentene 1000 25 24 h 50 23,000 (2.5) 50 cyclopentene
1000 25 24 h 52 9000 (3.5) 90 .sup.aDetermined by CH.sub.2Cl.sub.2
or THF GPC and results are reported relative to poly(styrene)
standards; .sup.bPercent trans olefin in the polymer backbone as
determined by 1H and 13C NMR analysis;
.sup.c1,4-diacetoxy-cis-2-butene was included as a chain transfer
agent ("CTA") wherein the Monomer/CTA = 80; .sup.dMonomer/CTA = 10,
[Monomer].sub.0 = 4.5M in C.sub.2H.sub.4Cl.sub.2; e Polymer was
insoluble; f Not determined.
[0076] Elevated temperatures (55.degree. C.) generally increased
the yields of polymer while reducing reaction times. The inclusion
of acyclic olefins which act as chain transfer agents controlled
the molecular weights. The addition of CTAs is desirable when
insoluble polymers are obtained by ring-opening monomers such as
COE in bulk. Polymers possessing alcohols or acetic ester along
their backbone could also be prepared using functionalized monomers
such as 5-hydroxy- or 5-acetoxy-cyclooctene. The functional groups
on these polymers could easily be derivatized to form graft
copolymers or side-chain liquid crystalline polymers. In general,
.sup.1H NMR spectroscopy indicated a predominantly (70-90%)
trans-olefin microstructure in these polymers. As expected for an
equilibrium controlled polymerization where chain transfer occurs,
longer polymerization times resulted in higher trans-olefins
values.
EXAMPLE 7
[0077] A highly strained monomer, exo,
exo-5,6-bis(methoxymethyl)-7-oxabicyclo[2.2.1]hept-2-ene, was
polymerized via ROMP reaction using catalyst 1 in the presence of
1,4-diacetoxy-2-butene as a chain transfer agent. The reaction was
conducted in C.sub.2H.sub.4Cl.sub.2 at 55.degree. C. for 24 hours
and resulted in a bis-(acetoxy) end-terminated polymer in 80% yield
(Mn=6300, PDI 2.0). This result is particularly notable since
telechelic polymers composed of highly strained monomers are
relatively difficult to obtain using other methods. For example, a
metathesis degradation approach using a tungsten analog of catalyst
8 has been used to prepare telechelic poly(oxanorbornene)s and
poly(norbornene)s. However, only certain telechelic polymers are
amenable to this approach since the limited ability of the tungsten
catalyst to tolerate functional groups imposes a severe restriction
on the range of chain transfer agents that may be used.
Alternatively, a "pulsed addition" approach has been used with
catalysts 7 and 8. However, because monomer and/or CTA must be
added in a carefully timed manner, this approach is relatively
difficult to perform and is not readily amenable to industrial
applications.
EXAMPLE 8
[0078] 1,5-dimethyl-1,5-cyclooctadiene, a sterically hindered, low
strain, di-substituted cyclic olefin was polymerized using catalyst
1. The 1,5-dimethyl-1,5-cyclooctadiene used in this study contained
1,6-dimethyl-1,5-cyclooctadiene (20%) as an inseparable mixture.
This ROMP reaction was performed at 55.degree. C. with
monomer/catalyst ration of 1000 and resulted in a 90% yield of
poly(isoprene) having a M.sub.n of 10,000 and a PDI of 2.3. To the
best of our knowledge, this example represents the first ROMP of
this monomer. Subsequently hydrogenation using
p-toluenesulfonhydrazide as a hydrogen source afforded an
ethylene-propylene copolymer in quantitative yield (as determined
by NMR analysis). Previously, a six step synthesis was necessary to
obtain a similar copolymer via a melathetical route.
[0079] The resulting ethylene-propylene copolymer was not
"perfectly" alternating because of the impurity in the
1,5-dimethyl-1-5-cyclooctadiene starting material. However, since
trisubstituted alkylidenes were not observed as a side product,
poly(isoprene) product having perfectly alternating head to tail
microstructure would have likely been formed if a higher grade of
1,5-dimethyl-1-5-cyclooctadiene were used. As a result, practice of
the present invention could result in a perfectly alternating
ethylene-propylene product.
EXAMPLE 9
[0080] 2-methyl-1-undecene (110 .mu.L, 0.5 mmol) and
5-hexenyl-1-acetate (170 .mu.L, 1.0 mmol) were simultaneously added
via syringe to a stirring solution of complex 1 (20 mg, 0.024 mmol,
4.8 mol %) in CH.sub.2Cl.sub.2 (2.5mL). The flask wasx fitted with
a condenser and refluxed under nitrogen for 12 hours. The reaction
mixture was then reduced in volume to 0.5 ml and purified directly
on a silica gel column (2.times.10 cm), cluting with 9:1
hexane:ethyl acetate. A clear oil was obtained (83 mg, 60% yield,
2.3:1 trans/cis as determined by relative intensity of alkene
.sup.13C peaks at 125.0 and 124.2 ppm). .sup.1H NMR (300 MHz,
CDCl.sub.3, ppm): 5.08 (1H, t, J=2.0 Hz), 4.04 (2H, t, J=6.0 Hz),
2.03 (3H, obs s), 2.01-1.91 (2H, m), 1.69-1.59 (2H, m), 1.56 (3H,
obs s), 1.47-1.05 (16H, broad m), 1.05-0.84 (3H, t, J=6.8 Hz)
.sup.13C NMR (75 MHz, CDCl.sub.3, ppm): 171.7, 136.7, 136.4, 125.0,
124.2, 123.3, 65.1, 40.3, 32.5, 32.3, 30.2, 29.9, 28.8, 28.6, 28.5,
28.0, 26.7, 23.2, 21.5, 16.4, 14.7. R.sub.f=0.35 (9:1 hexane:ethyl
acetate); HRMS (EI) calcd for C.sub.18H.sub.34O.sub.2 [M].sup.+
282.2559, found 282.2556.
EXAMPLE 10
[0081] 9-Decen-1(tert-butyldimethylsilane)-yl (330 .mu.L, 1.0 mmol)
and Methyl methacrylate (55 .mu.l, 0.51 mmol) were added
simultaneously via syringe to a stirring solution of complex 1 (21
mg, 0.026 mmol, 5.2 mol %) in CH.sub.2Cl.sub.2(2.5 ml). The flask
was fitted with a condenser and refluxed under nitrogen for 12
hours. The reaction mixture was then reduced in volume to 0.5 ml
and purified directly on a silica gel column (2.times.10 cm),
eluting with 9:1 hexane:ethyl acetate. A viscous oil was obtained
(110 mg, 62% yield, only trans isomer detected in .sup.1H and
.sup.13C NMR spectra). .sup.1H NMR (300 MHz, CDCl.sub.3, ppm);
.delta. 6.75 (1H, m), 3.71 (3H, s), 3.57 (2H, t, J=6.3 Hz), 2.14
(2H, m), 1.81 (3H, app s), 1.50-1.05 (12H, broad m), 0.87 (9H, s),
0.02 (6H, s). .sup.13C NMR (75 MHz, CDCl.sub.3, ppm): .delta.
169.2, 143.2, 128.0, 63.8, 52.1, 33.4, 30.0, 29.8, 29.2, 29.1,
26.5, 26.3, 18.9, 12.9. R.sub.f=0.81 (9:1 hexene:ethyl acetate);
HRMS (EI) calcd for C.sub.19H.sub.38O.sub.3Si [M+H].sup.+ 343.2668,
found 343.2677. Elemental analysis calcd: C: 66.61, H: 11.18;
found: C: 66.47, H: 11.03:
* * * * *