Synthesis, crystal structures, and reactivity of osmium(II) and -(IV) complexes containing a dithioimidodiphosphinate ligand.
Reduction of trans-[OsL2(O)2] (1) (L-=[N(i-Pr2PS)2]-) with hydrazine hydrate afforded a dinitrogen complex 2, possibly "[OsL2(N2)(solv)]" (solv=H2O or THF), which reacted with RCN, R'NC, and SO2 to give trans-[OsL2(RCN)2] (R=Ph (3), 4-tolyl (4), 4-t-BuC6H4 (5)), trans-[OsL2(R'NC)2] (R'=2,6-Me2C6H3 (xyl) (6), t-Bu (7)), and [Os(L)2(SO2)(H2O)] (8) complexes, respectively. Protonation of compounds 2, 3, and 6 with HBF4 led to formation of dicationic trans-[Os(LH)2(N2)(H2O)][BF4]2 (9), trans-[Os(LH)2(PhCN)2][BF4]2 (10), and trans-[Os(LH)2(xylNC)2][BF4]2 (11), respectively. Treatment of 1 with phenylhydrazine and SnCl2 afforded trans-[OsL2(N2Ph)2] (12) and trans-[OsL2Cl2] (13), respectively. Air oxidation of compound 2 in hexane/MeOH gave the dimethoxy complex trans-[OsL2(OMe)2] (14), which in CH2Cl2 solution was readily air oxidized to 1. Compound 1 is capable of catalyzing aerobic oxidation of PPh3, possibly via an Os(IV) intermediate. The formal potentials for the Os-L complexes have been determined by cyclic voltammetry. The solid-state structures of compounds 4, 6, cis-8, 13, and 14 have been established by X-ray crystallography.
Cheung
Wai-Man
WM
Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China. chleung@ust.hk
Zhang
Qian-Feng
QF
Williams
Ian D
ID
Leung
Wa-Hung
WH
D002384:Catalysis; D018360:Crystallography, X-Ray; D004164:Diphosphonates / Q000737:chemistry*; D004563:Electrochemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D017892:Osmium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D004164:Diphosphonates; D008024:Ligands; D017892:Osmium Compounds; D013438:Sulfhydryl Compounds; C522848:dithioimidodiphosphinate