Latent, high-activity olefin metathesis catalysts containing an N-heterocyclic carbene ligand
The invention provides novel organometallic complexes useful as olefin metathesis catalysts. The complexes have an N-heterocyclic carbene ligand and a chelating carbene ligand associated with a Group 8 transition metal center. The molecular structure of the complexes can be altered so as to provide a substantial latency period. The complexes are particularly useful in catalyzing ring closing metathesis of acyclic olefins and ring opening metathesis polymerization of cyclic olefins.
1. A method for catalyzing an olefin metathesis reaction, comprising contacting an olefinic reactant with a complex having the structure of formula (I)
wherein:
α and β represent single bonds or unsaturated bonds, with the proviso that α and β cannot both be unsaturated bonds;
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1;
when α is a single bond, L 2 is selected from NR 7 R 8 , PR 7 R 8 , N═CR 7 R 8 , and R 7 C═NR 8 , where R 7 and R 8 are independently selected from substituted and/or heteroatom-containing C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, and C 5 -C 24 aryl, or R 7 and R 8 can be taken together to form a heterocyclic ring;
when α is an unsaturated bond, L 2 is selected from NR′ and PR 7 , where R 7 is as defined previously, or L 2 and Z represent adjacent atoms in an aromatic ring;
Y and Z are linkages independently selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, and further wherein Y and Z may represent adjacent atoms in an aromatic ring;
m is zero or 1;
n is zero or 1; and wherein
L 2 and the ligand containing Q are bonded to M in a trans orientation, and wherein the olefinic reactant and the complex having the structure of formula (I) are contacted under reaction conditions selected to enable olefin metathesis; and wherein the complex having the structure of formula (I) exhibits a latency period when contacted with the olefinic reactant.
2. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure of formula (II)
wherein:
β represents a single bond or an unsaturated bond;
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1;
R 7 and R 8 are independently selected from substituted and/or heteroatom-containing C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, and C 5 -C 24 aryl, or R 7 and R 8 can be taken together to form a heterocyclic ring;
Y and Z are linkages independently selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, and further wherein Y and Z may represent adjacent atoms in an aromatic ring; and
wherein NR 7 R 8 and the ligand containing Q are bonded to M in a trans orientation.
3. The method for catalyzing an olefin metathesis reaction according to claim 2 , wherein R 7 and R 8 of the complex having the structure of formula (II) are C 1 -C 12 alkyl or C 5 -C 12 aryl, and Y is a substituted or unsubstituted methylene or ethylene linkage.
4. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure of formula (III)
wherein:
β represents a single bond or an unsaturated bond;
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1;
R 7 and R 8 are independently selected from substituted and/or heteroatom-containing C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, and C 5 -C 24 aryl, or R 7 and R 8 can be taken together to form a heterocyclic ring;
Y and Z are linkages independently selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, and further wherein Y and Z may represent adjacent atoms in an aromatic ring; and
wherein PR 7 R 8 and the ligand containing Q are bonded to M in a trans orientation.
5. The method for catalyzing an olefin metathesis reaction according to claim 4 , wherein R 7 and R 8 of the complex having the structure of formula (III) are C 1 -C 12 alkyl or C 5 -C 12 aryl, and Y is a substituted or unsubstituted methylene or ethylene linkage.
6. The method for catalyzing an olefin metathesis reaction according to claim 5 , wherein R 7 and R 8 of the complex having the structure of formula (III) are phenyl and Y is ethylene.
7. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure of formula (IV)
wherein:
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1;
Y is a linkage selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl; and wherein
the complex has a pyridine ligand,
wherein the pyridine ligand and the ligand containing Q are bonded to M in a trans orientation.
8. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure of formula (V)
wherein:
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1; and
R 7 is selected from substituted and/or heteroatom-containing C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, and C 5 -C 24 aryl;
Y and Z are linkages independently selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl; and
wherein NR′ and the ligand containing Q are bonded to M in a trans orientation.
9. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex is selected from:
10. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure:
11. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex has the structure:
12. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex is selected from:
13. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex is selected from:
14. The method for catalyzing an olefin metathesis reaction according to claim 1 , wherein the complex is selected from:
15. A method for controlling the reaction latency period of an olefin metathesis reaction, comprising combining an olefin metathesis reaction mixture with an organometallic complex comprising a Group 8 transition metal having an N-heterocyclic carbene ligand and a chelating carbene ligand, wherein the olefin metathesis reaction mixture and the organometallic complex are combined under reaction conditions selected to enable olefin metathesis, and wherein the organometallic complex exhibits a latency period of at least two minutes when combined with the olefin metathesis reaction mixture.
16. The method for controlling the reaction latency period of an olefin metathesis reaction according to claim 15 , wherein the olefin metathesis reaction is ring opening metathesis polymerization.
17. The method for controlling the reaction latency period of an olefin metathesis reaction according to claim 15 , wherein the olefin metathesis reaction is ring closing metathesis.
18. A method for controlling the reaction latency period of an olefin metathesis reaction, comprising combining an olefin metathesis reaction mixture with a complex having the structure of formula (I)
wherein:
α and β represent single bonds or unsaturated bonds, with the proviso that α and β cannot both be unsaturated bonds;
M is a Group 8 transition metal;
R 1 and R 2 are independently selected from hydrogen, hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, substituted heteroatom-containing hydrocarbyl, and functional groups;
Q is an organic diradical;
X 1 and X 2 are anionic ligands, and may be the same or different;
L 1 is a neutral electron donor ligand, and p is zero or 1;
when α is a single bond, L 2 is selected from NR 7 R 8 , PR 7 R 8 , N═CR 7 R 8 , and R 7 C═NR 8 , where R 7 and R 8 are independently selected from substituted and/or heteroatom-containing C 1 -C 20 alkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, and C 5 -C 24 aryl, or R 7 and R 8 can be taken together to form a heterocyclic ring;
when α is an unsaturated bond, L 2 is selected from NR′ and PR 7 , where R 7 is as defined previously, or L 2 and Z represent adjacent atoms in an aromatic ring;
Y and Z are linkages independently selected from hydrocarbylene, substituted hydrocarbylene, heteroatom-containing hydrocarbylene, substituted heteroatom-containing hydrocarbylene, —O—, —S—, —NR 9 , and —PR 9 —, wherein R 9 is selected from hydrocarbyl, substituted hydrocarbyl, heteroatom-containing hydrocarbyl, and substituted heteroatom-containing hydrocarbyl, and further wherein Y and Z may represent adjacent atoms in an aromatic ring;
m is zero or 1;
n is zero or 1; and wherein
L 2 and the ligand containing Q are bonded to M in a trans orientation, and wherein the olefin metathesis reaction mixture and the complex having the structure of formula (I) are combined under reaction conditions selected to enable olefin metathesis.
19. The method for controlling the reaction latency period of an olefin metathesis reaction according to claim 18 , wherein the complex having the structure of formula (I) exhibits a latency period when combined with the olefin metathesis reaction mixture.
20. The method for controlling the reaction latency period of an olefin metathesis reaction according to claim 19 , wherein the latency period is at least two minutes.
21. The method for controlling the reaction latency period of an olefin metathesis reaction according to claim 18 , wherein the complex has the structure: