Pd(II) bromide complexes of 1,2-bis(diphenylphosphino)-1,2-dicarba-closo-dodecaborane. Crystal structures of [PdBr2(1,2-(PPh2)(2)-1,2-C2B10H10)]center dot CH2Cl2, [PdBr1.133Cl0.867(1,2-(PPh2)(2)-1,2-C2B10H10)]center dot CH2Cl2 and [PdBrCl0.541Me0.459

摘要

The revised synthesis of [PdBr2(1,2-(PPh2)(2)-1,2-C2B10H10)] (1) is described. The pure complex 1 was obtained by several days reaction of [PdCl2(1,2-(PPh2)(2)-1,2-C2B10H10)] with an excess of KBr. Refluxing of 2 h produced partially brominated product [PdBr1.133Cl0.867(1,2-(PPh2)(2)-1,2-C2B10H10)] (2), thus showing that the earlier reported reaction time of I h is too short. The reaction of Mg and an excess of MeBr with [PdClMe(1,2-(PPh2)(2)-1,2-C2B10H10)] yielded a mixture of novel complexes [PdBrCl(1,2-(PPh2)(2)-1,2-C2B10H10)] and [PdBrMe(1,2-(PPh2)(2)-1,2-C2B10H10)]. The structures were confirmed by NMR and X-ray crystallographic studies. The structures of 1 (.) CH2Cl2 and 2 (.) CH2Cl2 are isostructural, and they are also isostructural with the earlier published structure of [PdCl2(1,2-(PPh2)(2)-1,2-C2B10H10)] (.) CH2Cl2. Thus, most probably, these complexes form a solid solution where the composition of the lattice varies from dibromide complex to dichloride complex. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 22]