Dipalladium bis(μ-isopropylthiolato) complexes with a [Pd 2S2] core supported by N-heterocyclic carbenes

Abstract

The reaction of Pd(OAc)2 with 1,3-dibenzylbenzimidazolium bromide (A) and 1-propyl-3-methylbenzimidazolium iodide (B) afforded the dihalo-bis(carbene) complexes cis-[PdBr2(Bz2-bimy) 2] (1) and cis-[PdI2(Pr,Me-bimy)2] (2), respectively. Halide substitution of 1 and 2 with AgO2CCH3 gave the mixed diacetato-bis(carbene) complexes cis-[Pd(O2CCH 3)2(Bz2-bimy)2] (3) and cis-[Pd(O2CCH3)2(Pr,Me-bimy)2] (4). In situ deprotonation of isopropylthiol with the mixed carbene-carboxylato complexes 3 and 4 yielded the novel dipalladium complexes [Pd 2(μ-iPr-S)2(Bz2-bimy)4](BF 4)2 (5) and [Pd2(μ-iPr-S) 2(Pr,Me-bimy)4](BF4)2 (6) with a [Pd2S2] core solely supported by N-heterocyclic carbenes. All compounds have been fully characterized by multinuclei NMR spectroscopies and ESI mass spectrometry. The solid state molecular structures of complexes 2, 3, 5, and 6 have also been confirmed by X-ray diffraction studies. © 2007 American Chemical Society.