Polynuclear cyclometallated palladium(II) complexes. Crystal and molecular structures of [(PPh3)(Cl)PdN(Cy)C(H)C6H2C(H)N(Cy) Pd(Cl)(PPh3)] and [{PdN(Cy)C(H)C6H2C(H)N(Cy)Pd}{Ph2PC(H)C(H)PPh2-P,P}2][ClO4]2

Treatment of N,N-terephthalylidenebis(cyclohexylamine) (L) with palladium(II) acetate in toluene at room temperature gave the dicyclometallated acetato-bridged complex [(OAc)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(OAc)]n (1). Reaction of 1 with lithium chloride or bromide in acetone produced the chloro- or bromo-bridged complexes [(Cl)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(Cl)]n (2) and [(Br)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(Br)]n (3), respectively. Reaction of 2 with triphenylphosphine gave [(PPh3)(Cl)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(Cl)(PPh3)] (4). Treatment of 2 and 3 with bis(diphenylphosphino)methane and 1,5-bis(diphenylphosphino)pentane in a 1:1 molar ratio afforded [{(Cl)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(Cl)}2{μ-Ph2PCH2PPh2}2] (5) and [{(Br)PdN(Cy)C(H)C6H2C(H)N(Cy)Pd(Br)}2{μ-Ph2P(CH2)5PPh2}2] (6), respectively. Reaction of 2 and 3 with bis(diphenylphosphino)methane or cis-1,5-bis(diphenylphosphino)ethene, in a 1:2 molar ratio, and sodium perchlorate, gave dinuclear cyclometallated compounds with two chelated phosphine ligands [{PdN(Cy)C(H)C6H2C(H)N(Cy)Pd}{Ph2PCH2PPh2-P,P}2][ClO4]2 (7) and [{PdN(Cy)C(H)C6H2C(H)N(Cy)Pd}{Ph2PC(H)C(H)PPh2-P,P}2][ClO4]2 (8). The compounds have been fully characterized by elemental analysis, mass spectrometry, IR and NMR spectroscopy, and complexes 4 and 8 by X-ray crystallography.