New dinuclear diphenylphosphido-bridged palladium(I) derivatives and the X-ray crystal and molecular structures of the mononuclear homoleptic diphenylphosphine complexes Pd(PPh-2H)_4 and [Pd(PPh_2H)_4](BF_4)_2

摘要

By reacting CpPd(#eta#~3-C_3H_5) with PPh_2H we isolated the doubly bridged dinuclear complex [Pd_2(μ-PPh_2)_2(PPh_2H)_3] (1). This reacts with with HBF_4 yielding the mono-phosphido-bridged cationic derivative [Pd-2(μ-PPh_2)(PPh_2H)_4]BF_4 (2)BF_4, arising from the protonation of one of the bridging phosphides. Contrary to our previous data on the parent t-butyl systems, a mononuclear homoleptic phosphine complex is not an intermediate in the formation of 1. Pd(PPh_2H)_4 (3), was in fact prepared by an independent route and was shown to decompose thermally to another (uncharacterized) polynuclear derivative; fluoboric acid reacts with 3 yielding its palladium(II) analogue [Pd(PPh_2H)_4(BF_4)_2, (3)(BF_4)_2, with dihydrogen evolution. We also report the crystal and molecular structures of 3 and (3) (BF_4)_2, the first homoleptic transition metal complexes of diphenylphosphine to be structurally characterized.