First-row transition metal hydrogenation and hydrosilylation catalysts
Transition metal compounds, and specifically transition metal compounds having a tetradentate and/or pentadentate supporting ligand are described, together with methods for the preparation thereof and the use of such compounds as hydrogenation and/or hydrosilylation catalysts.
1. A first row transition metal complex having a tetradentate or pentadentate supporting ligand, wherein the metal complex comprises a chemical structure as follows:
wherein:
M is Mn, Fe, Co, Ni, or a combination thereof;
each X is a donor group independently selected from PR n , NR n , AsR n , SbR n , BiR n , OR n , SR n , SeR n , TeR n , where n=2, 1, or 0, a 3-7 membered saturated or unsaturated heterocycle containing one or more of a donor atom selected from P, N, As, Sb, Bi, O, S, Se, or Te, and any combination thereof;
each R is independently selected from hydrogen, an inert functional group, a substituted, unsubstituted, or cyclic C 1-24 alkyl group optionally having one or more heteroatoms, an aryl or substituted aryl group that optionally contains one or more heteroatoms, a moiety where two R groups taken together form a ring that is a substituted or unsubstituted, saturated or unsaturated cyclic structure that optionally contains one or more heteroatoms, a halogen, an alkoxide, an amide, a silyl, a boryl, and combinations thereof;
each Y is independently selected from a substituted or unsubstituted C 2-3 alkylene linking group optionally having one or more heteroatoms but not an aryl functionality directly attached to N;
or a salt thereof.
2. The metal complex of claim 1 , wherein:
M is Mn, Fe, Co, or Ni; and
each X is independently selected from PR 2 , NR 2 , and any other donor group.
3. A catalytic composition comprising the metal complex of claim 1 .
4. A method for reducing one or more organic substrates comprising contacting a composition comprising one or more organic substrates with a catalytic composition comprising a metal complex according to claim 1 in the presence of a reductant, whereby the one or more organic substrates are reduced.
5. The method of claim 4 , wherein the reductant is a silane, a substituted silane, an alkoxysilane, hydrogen, a substituted borane, a substituted alane, or a mixture thereof.
6. The method of claim 4 , wherein the one or more organic substrates contain a ketone, an ester, or mixtures thereof.
7. The method of claim 6 , wherein the one or more organic substrates include an unsaturated organic compound.
8. The method of claim 7 , wherein the unsaturated organic compound is an olefin or an alkyne.
9. A method of facilitating a hydrosilylation reaction, comprising reacting a compound comprising an Si—H bond with an unsaturated organic compound in the presence of one or more of the metal complexes of claim 1 .
10. The method of claim 9 , whereby the Si and H atoms in the Si—H bond are added across an unsaturated bond in the unsaturated organic compound to form an organosilicon compound.
11. A method of facilitating a hydrogenation reaction, comprising reacting H 2 with an unsaturated organic compound in the presence of one or more of the metal complexes of claim 1 .
12. The method of claim 11 , whereby the H atoms in the H2 are added across an unsaturated bond in the unsaturated organic compound to reduce the unsaturated bond.