Crystal Structures of Two Palladacycles from the C–H Activation of 2-(Thiophen-2-yl)pyridine

Abstract

A C,N-bound palladacycle dimer has been synthesised by reaction of 2-(thiophen-2-yl)pyridine, LH, with palladium acetate in acetic acid. Characterisation by single crystal X-ray diffraction showed the palladacycle dimer, [(L)Pd(OAc)]2, to crystallise in the monoclinic space group P21/n with cell parameters a = 9.5853(1) A, b = 19.1332(3) A, c = 12.3889(2) A, β = 103.732(1)°. Reaction of [(L)Pd(OAc)]2 with triphenylphosphine afforded a trans-substituted monomeric complex, [(L)PdPPh3(OAc)] which was also analysed using single crystal X-ray diffraction. [(L)PdPPh3(OAc)] crystallises in the monoclinic space group P21/c with cell parameters a = 9.4839(1) A, b = 11.0427(2) A, c = 26.0770(4) A, β = 95.022(1)°. A 2-(thiophen-2-yl)pyridine-based C,N-bound palladacycle dimer and its corresponding monomer have been characterised and are discussed with reference to other 2-(thiophen-2-yl)pyridine-based palladacycles in the literature.