Catalytic hydrogenation using complexes of base metals with tridentate ligands
View Patent ↗Complexes of cobalt and nickel with tridentate ligand PNHP R are effective for hydrogenation of unsaturated compounds. Cobalt complex [(PNHP Cy )Co(CH 2 SiMe 3 )]BAr F 4 (PNHP Cy =bis[2-(dicyclohexylphosphino)ethyl]amine, BAr F 4 =B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 )) was prepared and used with hydrogen for hydrogenation of alkenes, aldehydes, ketones, and imines under mild conditions (25-60° C., 1-4 atm H 2 ). Nickel complex [(PNHP Cy )Ni(H)]BPh 4 was used for hydrogenation of styrene and 1-octene under mild conditions. (PNP Cy )Ni(H) was used for hydrogenating alkenes.
1. A composition of the formula
wherein each R 1 is independently selected from cycloalkyl, alkyl, substituted alkyl, phenyl, or substituted phenyl;
wherein R 2 is —CH 2 Si(CH 3 ) 3 , H, alkyl, substituted alkyl, phenyl, substituted phenyl, alkoxide, or amido;
wherein M is cobalt or nickel; and
wherein X is a counterion.
2. The composition of claim 1 , wherein the counterion X is tetraphenylborate, hexafluorophosphate, B(C 6 F 5 ) 4 , or B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
3. The composition of claim 2 , wherein M is cobalt, R 2 is —CH 2 Si(CH 3 ) 3 , and X is B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
4. The composition of claim 2 , wherein M is cobalt, R 2 is H, and X is B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
5. The composition of claim 2 , wherein M is cobalt, R 2 is alkyl, and X is B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
6. The composition of claim 2 , wherein M is nickel, R 2 is H, and X is tetraphenylborate, hexafluorophosphate, or B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
7. A composition of the formula
wherein each R 1 is independently selected from cycloalkyl, alkyl, substituted alkyl, phenyl, or substituted phenyl;
wherein R 2 is —CH 2 Si(CH 3 ) 3 , H, alkyl, substituted alkyl, phenyl, substituted phenyl, alkoxide, or amido; and
wherein M is cobalt or nickel.
8. The composition of claim 6 , wherein M is cobalt and R 2 is —CH 2 Si(CH 3 ) 3 .
9. The composition of claim 6 , wherein M is nickel and R 2 is H.
10. A process for hydrogenation of an unsaturated compound, the process comprising:
combining the composition of claim 1 with hydrogen and an unsaturated compound under conditions effective for the hydrogenation of the unsaturated compound.
11. The process of claim 10 , wherein M is cobalt.
12. The process of claim 11 , wherein R 2 is H.
13. The process of claim 12 , wherein the counterion X is B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
14. The process of claim 11 , wherein M is nickel.
15. The process of claim 14 , wherein X is B(3,5-(CF 3 ) 2 C 6 H 3 ) 4 .
16. The process of claim 10 , wherein the unsaturated compound comprises a carbon-carbon double or triple bond that becomes hydrogenated as a result of the process.
17. The process of claim 10 , wherein the unsaturated compound comprises a carbon-oxygen double bond that becomes hydrogenated as a result of the process.
18. The process of claim 10 , wherein the unsaturated compound comprises a carbon-nitrogen double or triple bond that becomes hydrogenated as a result of the process.
19. A process for hydrogenation of an unsaturated compound, the process comprising combining a solution of the composition of claim 1 with hydrogen and an unsaturated compound under conditions effective for the hydrogenation of the unsaturated compound.