Polynuclear cyclometallated palladium(II) complexes. Crystal and molecular structures of [(PPh 3)(Cl)PdN(Cy)C(H)C 6H 2C(H)N(Cy) Pd(Cl)(PPh 3)] and [{PdN(Cy)C(H)C 6H 2C(H)N(Cy)Pd}{Ph 2PC(H)C(H)PPh 2- P, P} 2][ClO 4] 2

• Published in: Journal of organometallic chemistry 2002-08, Vol.655 (1), p.127-133
• Main Authors: López-Torres, Margarita, Fernández, Alberto, Fernández, Jesús J, Suárez, Antonio, Castro-Juiz, Samuel, Pereira, M a Teresa, Vila, José M
• Format: Article
• Language: English
• Subjects: Cyclometallation; Palladium(II); Phosphines; Schiff-base
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(02)01468-7

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)C 6H 2C(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)C 6H 2C(H)N(Cy)Pd(Cl)] n ( 2) and [(Br)PdN(Cy)C(H)C 6H 2C(H)N(Cy)Pd(Br)] n ( 3), respectively. Reaction of 2 with triphenylphosphine gave [(PPh 3)(Cl)PdN(Cy)C(H)C 6H 2C(H)N(Cy)Pd(Cl)(PPh 3)] ( 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)C 6H 2C(H)N(Cy)Pd(Cl)} 2{μ-Ph 2PCH 2PPh 2} 2] ( 5) and [{(Br)PdN(Cy)C(H)C 6H 2C(H)N(Cy)Pd(Br)} 2{μ-Ph 2P(CH 2) 5PPh 2} 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)C 6H 2C(H)N(Cy)Pd}{Ph 2PCH 2PPh 2- P, P} 2][ClO 4] 2 ( 7) and [{PdN(Cy)C(H)C 6H 2C(H)N(Cy)Pd}{Ph 2PC(H)C(H)PPh 2- P, P} 2][ClO 4] 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. Dicyclometallated palladium(II) compounds with Schiff-bases were prepared with the ligand bonded in a tetradentate [C,N:C,N] manner. They readily react with tertiary phosphines to yield polynuclear or tetranuclear species.