Synthesis and reactivity of binuclear copper(I) complexes of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L1). Crystal structures of [Cu2(µ-L1)2(MeCN)2][ClO4]2, [Cu2(µ-L1)2(µ-η1-CCPh)][ClO4]· CHCl3·H2O and [Cu2(µ-L1)2(µ-Cl)][ClO4]·H2O

Abstract

Reaction of 2-(diphenylphosphino)-6-(pyrazol-1-yl)pyridine (L¹) with 1 equivalent of [Cu(MeCN)₄][ClO₄] resulted in the formation of [Cu₂(µ-L¹)₂(MeCN)₂][ClO₄]₂ 1. Complex 1 reacted with Li(CCPh) to give [Cu₂(µ-L¹)₂(µ-η¹-CCPh)][ClO₄] 2, which underwent an alkynyl ligand-transfer reaction with [Pd(PBuⁿ₃)₂Cl₂] to give [Cu₂(µ-L¹)₂(µ-Cl)][ClO₄] 3 and [Pd(PBuⁿ₃)₂(CCPh)Cl]. Reaction of 1 with dimethyl acetylenedicarboxylate yielded [Cu₂(µ-L¹)₂(µ-MeO₂CCCCO₂Me)][ClO₄]₂ 4, the alkynyl ligand of which can easily be displaced by bis(diphenylphosphino)methane (dppm) to give [Cu₂(µ-L¹)₂(µ-dppm)][ClO₄]₂ 5. The crystal structures of 1, 2·CHCl₃·H₂O and 3·H₂O have been determined.