Cyclometallated compounds of Pd(II): CN to CO conversion through acid hydrolysis. Crystal and molecular structures of [Pd{4-(CHO)C 6H 3C(H)NCy}(Cl)(PPh 3) 2] and [Pd{2,4-(CHO) 2C 6H 3}(Cl)(PPh 3) 2

Abstract

Treatment of the chloro-bridged complex [Pd{4-(CHO)C 6H 3C(H)NCy}(Cl)] 2 ( 1) with tertiary monophosphines in a 1:4 molar ratio gave the non-cyclometallated monomer complexes [Pd{4-(CHO)C 6H 3C(H)NCy}(Cl)(PR 3) 2] (PR 3: ( 2) PPh 3, ( 3) PEtPh 2, ( 4) PEt 2Ph, ( 5) PMePh 2). The crystal structure of 2 is described. Reaction of complexes 2– 5 with a mixture of glacial acetic acid–water gave the monomeric complexes [Pd{2,4-(CHO) 2C 6H 3}(Cl)(PR 3) 2] (PR 3 ( 6), PPh 3 ( 7), PEtPh 2 ( 8), PEt 2Ph ( 9), PMePh 2) after cleavage of the CN group. Complex 6 was characterized crystallographically. Treatment of 1 with the triphosphine bis(2-diphenylphosphinoethyl)phenylphosphine in 1:2 molar ratio gave the mononuclear complex [Pd{4-(CHO)C 6H 3C(H)NCy}{Ph 2P(CH 2) 2PPh(CH 2) 2PPh 2- P, P, P}][Cl] ( 10) in which the phosphine is coordinated through the three phosphorus atoms. Treatment of 10 with a mixture of acetic acid–water also caused cleavage of the CN bond giving the complex [Pd{2,4-(CHO) 2C 6H 3}{Ph 2P(CH 2) 2PPh(CH 2) 2PPh 2- P, P, P}][Cl] ( 11).