Polydentate ligands and their complexes for molecular catalysis
Embodiments of the present disclosure relate generally to novel achiral and chiral sulfur-, nitrogen- and phosphorus-containing ligands, designated as NNS-type, P(O)NS-type, PNS-type, SNNS-type, SNNP(O)-type, or SNNP-type polydentate ligands and transition metal complexes of these ligands, including iridium complexes having PNS-type and NNS-type ligands. The catalysts derived from these ligands and transition metal complexes may be used in a wide range of catalytic reactions, including hydrogenation and transfer hydrogenation of unsaturated organic compounds, dehydrogenation of alcohols and boranes, various dehydrogenative couplings, chemoselective hydrogenation of α,β-unsaturated alcohols, and other catalytic transformations.
1. A ligand having a structure represented by Formula (I):
wherein:
E is:
R 1 is a substituted or unsubstituted C 1-6 alkyl group, a substituted or unsubstituted C 3-6 cycloalkyl group, an unsubstituted phenyl group, a substituted or unsubstituted tolyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted diphenylether group, a substituted or unsubstituted diphenylamine group, a substituted or unsubstituted benzophenone group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted arylalkyl group;
R 2 is H, a substituted or unsubstituted C 1-6 alkyl group, a substituted or unsubstituted C 3-5 cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, or a substituted or unsubstituted arylalkyl group;
R 5 is independently at each occurrence a substituted or unsubstituted C 1-6 alkyl group, a substituted or unsubstituted C 3-6 cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted aryloxy group;
m is 1, 2, 3, 4, or 5;
n is 1, 2, 3, 4, or 5; and
z is 1.
2. The ligand of claim 1 , wherein R 1 is methyl, ethyl, propyl, isopropyl, 1-butyl, 2-butyl, isobutyl, tert-butyl, benzyl (-Bn), or phenyl (-Ph).
3. The ligand of claim 2 , wherein R 1 is benzyl (-Bn).
4. The ligand of claim 1 , wherein R 2 is H, methyl, ethyl, propyl, isopropyl, 1-butyl, 2-butyl, isobutyl, tert-butyl, benzyl (-Bn), or phenyl (-Ph).
5. The ligand of claim 1 , wherein E is diarylphosphine oxide, dialkylphosphine oxide, or alkylarylphosphine oxide.
6. The ligand of claim 1 , wherein m and n are each independently 1 or 2.
7. The ligand of claim 1 , the ligand having a structure of:
8. The ligand of claim 1 , wherein R 1 is a substituted or unsubstituted C 1-6 alkyl group.
9. The ligand of claim 1 , wherein R 1 is a substituted or unsubstituted arylalkyl group.
10. The ligand of claim 1 , wherein R 1 is methyl.
11. The ligand of claim 1 , wherein R 2 is H.
12. The ligand of claim 1 , wherein R 2 is methyl.
13. The ligand of claim 1 , wherein each R 5 is phenyl.
14. The ligand of claim 1 , wherein at least one R 5 is phenyl.
15. The ligand of claim 1 , wherein at least one R 5 is a substituted or unsubstituted aryl group.
16. The ligand of claim 1 , wherein at least one R 5 is a substituted or unsubstituted C 1-6 alkyl group.
17. The ligand of claim 1 , wherein at least one R 5 is a substituted or unsubstituted C 3-6 cycloalkyl group.
18. The ligand of claim 8 , wherein R 2 is H or methyl, and at least one R 5 is a substituted or unsubstituted aryl group.
19. The ligand of claim 18 , wherein each R 5 is phenyl.
20. The ligand of claim 1 , wherein the ligand is: