N, S-chelating amino-ortho-carboranethiolate complexes of rhodium and iridium: synthesis and reactivity. X-ray crystal structures of (#eta#~4-C_8H_(12))Rh[(NMe_2CH_2)SC_2B_(10)H_(10)] and (CO)_2 Rh[(NMe_2CH_2)SC_2B_(10)H_(10)]

摘要

The reaction of [M(#mu#-Cl)(cod)]_2 (M = Rh, Ir; cod = cycloocta-1, 5-diene) with two equivalents of the lithium ortho-carboranethiolate derivative LiCab~(N,S) 2 [LiCab~(N,S) = closo-2-(dimethylamino-methyl)-1-(lithiumthiolato)-ortho-carborane] produced the four-coordinated metallacyclic compounds, Cab~(N,S)M(cod) 3 (M = Rh 3a, Ir 3b), in which the metal atom was stabilized via intramolecular N, S-coordination. These new compounds have been isolated in high yields and characterized by IR and NMR spectroscopy. The structure consists of an amino-ortho-carboranethiolate fragment bonded to (cod)Rh(I) via nitrogen and sulfur, so as to give the metal a square-planar environment. Subsequent carbonylation reactions of 3a, 3b result in the quantitative formation of the corresponding (amino-ortho-carboranethiolato) (carbonyl) metal N, S-chelates Cab~(N,S)M(CO)~2 4 (M = Rh 4a, Ir 4b). The metal carbonyl complexes 4a, 4b have been isolated and characterized by spectroscopic and compound 4a also by X-ray diffraction techniques. The molecular structure of 4a reveals that the rhodium atom is coordinated by nitrogen and sulfur atoms of the amino-ortho-carboranethiolate ligand, and two carbonyl ligands complete the coordination of the metal atom.