Synthesis, characterization and crystal structures of cyclometallated palladium (II) compounds containing difunctional ligands with [P,P], [As,As], [N,N], [P,As], [P,N] and [P,O] donor atoms

Treatment of the chloro-bridged dinuclear complex [Pd{3,4-(MeO) 2C6H2C(H)=N(Cy)-C6,N}(mu-Cl)](2) (1) with homobidentate [P,P], [As, As], [N,N], and heterobidentate [P,As], [P,N] ligands in a 1:1 molar ratio gave the dinuclear complexes [{Pd[3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6, N](Cl)}(2){mu-L}] (L = Ph2PC4H6(NH)CH2PPh2 (2); Ph2As(CH2)(2)AsPh2 (3); 1,3-(NH2CH2)(2)C6H4 (4); Ph2P(CH2)(2)AsPh2 (5); Ph2P(CH2)(2)NH2 (6)), with the bidentate ligands bridging the two cyclometallated fragments. The reaction with the homobidentate ligands in a 1:2 molar ratio in the presence of NaClO4 afforded the mononuclear compounds [[Pd{3,4-( MeO)(2)C6H2C(H)=N(Cy)-C6,N}{L=P,P}][ClO4] (L=Ph2PC4H6(NH)CH2PPh2 (7); (o-Tol)(2)P(CH2)(2)P(o-Tol)(2) (8)), [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6,N}{Ph2As(CH2)(2)AsPh2-As,As}][ ClO4] ( 9) and [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6,N}{L-N,N}][ClO4] (L = NH2(CH2)(3)NH2 (10); NH2(C6H8)CH2(C6H8)NH2 (11); 1,3-(NH2CH2)(2)C6H4 (12); 1,3-(NH2)(2)C5H3N (13); NH2(C6H4)O(C6H4)NH2 (14); NMe2(CH2)(2)NMe2 (15)), in which the chloro ligands are absent and the bidentate ligands are chelated to the palladium atom. Reaction of 1 with Ph2P(CH2)(2)AsPh2 in 1: 2 molar ratio in acetone in the presence of NH4PF6 afforded the analogous mononuclear compound [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6,N}{Ph2P(CH2)(2)AsPh2-P,As}][PF6] (16); whereas reaction with Ph2P(CH2)(3)NH2 gave [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6,N}{Ph2P(CH2)(3)N-( C=Me-2)-P,N}][PF6] (17), derived from intermolecular condensation between the aminophosphine and acetone. Condensation of the NH2 group was precluded by change of solvent, using dichloromethane. acetone. Condensation of the NH2 group was precluded by change of solvent, using dichloromethane. Iminophoshines also reacted with 1 in 1: 2 molar ratio in acetone to give a new series of mononuclear cyclometallated complexes: [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C6,N}{L- P,N}][ClO4] (L=Ph2PC6H4C(H) =NCy (20); Ph2PC6H4C(H)=NC(CH3)(3) (21); Ph2PC6H4C(H)=NNMe2 (22); Ph2PC6H4C(H)=NNHMe (23); Ph2PC6H4C(H)=NNHPh (24)). Analogous complexes with a stable P,O-chelate were obtained using bidentate [P,O] donor ligands: [Pd{3,4-(MeO)(2)C6H2C(H)=N(Cy)-C-6,N}{L-P,O}][Cl] (L = 2-(Ph2P)C6H4CHO (25); Ph2PN(Me)C=O)Me (26)). The crystal structures of compounds 1, 5, 15, 16, 18, 20 have been determined by X-ray crystallography. (C) 2008 Elsevier B. V. All rights reserved.