A New Type of Tweezer Complex Involving a Rhenium−Rhenium Multiple Bond That Enforces an Unusual Structure in a Dipalladium(II) Unit

Abstract

The substitution of the μ-acetato ligands in cis-Re2(μ-O2CCH3)2Cl2(μ-dppm)2 (1, dppm = Ph2PCH2PPh2) and trans-Re2(μ-O2CCH3)2Cl2(μ-dppE)2 (2, dppE = Ph2PC(CH2)PPh2) by [4-Ph2PC6H4CO2]- occurs with retention of stereochemistry to give cis-Re2(μ-O2CC6H4-4-PPh2)2Cl2(μ-dppm)2 (3) and trans-Re2(μ-O2CC6H4-4-PPh2)2Cl2(μ-dppE)2 (6), respectively. The uncoordinated phosphine groups in complexes 3 and 6 have been used to form mixed-metal assemblies with Au(I) and Pd(II), including the Re2Pd2 complex cis-Re2(μ-O2CC6H4-4-PPh2)2Cl2(μ-dppm)2(Pd2Cl4) (5), in which the planar [(P)ClPd(μ-Cl)2PdCl(P)] unit has the unusual cis structure. The crystal structures of 3 and 5 have been determined