Heterobimetallic Ti/Co Complexes That Promote Catalytic N-N Bond Cleavage.
Treatment of the tris(phosphinoamide) titanium precursor ClTi(XylNP(i)Pr2)3 (1) with CoI2 leads to the heterobimetallic complex (η(2)-(i)Pr2PNXyl)Ti(XylNP(i)Pr2)2(μ-Cl)CoI (2). One-electron reduction of 2 affords (η(2)-(i)Pr2PNXyl)Ti(XylNP(i)Pr2)2CoI (3), which can be reduced by another electron under dinitrogen to generate the reduced diamagnetic complex (THF)Ti(XylNP(i)Pr2)3CoN2 (4). The removal of the dinitrogen ligand from 4 under vacuum affords (THF)Ti(XylNP(i)Pr2)3Co (5), which features a Ti-Co triple bond. Treatment of 4 with hydrazine or methyl hydrazine results in N-N bond cleavage and affords the new diamagnetic complexes (L)Ti(XylNP(i)Pr2)3CoN2 (L = NH3 (6), MeNH2 (7)). Complexes 4, 5, and 6 have been shown to catalyze the disproportionation of hydrazine into ammonia and dinitrogen gas through a mechanism involving a diazene intermediate.
Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Bing
B
Wu
Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Kathryn M
KM
Gramigna
Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Mark W
MW
Bezpalko
Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Bruce M
BM
Foxman
Department of Chemistry, Brandeis University , 415 South Street, Waltham, Massachusetts 02454, United States.
Christine M
CM
Thomas