Eddie Y. Y. Chan

Metal complexes of a chiral quadridentate Schiff base

Chiral metal Schiff-base complexes [AlL(Et)], [TiLCl2], [VO(L)], [(FeL)2O], [CoL], [NiL], [CuL], [ZrLCl2], [RuL(CO)2] and trans-[RuL(NO)Cl]([H2L =(R,R)-(–)-N,N′-bis(3,5-di-tert-butylsalicylidene)cyclohexane-1,2-diamine] were synthesized and characterized. The structures of [CoL] and trans-[RuL(NO)Cl] have been established by X-ray crystallography. The former has a pseudo-square-planar geometry with Co–N and Co–O distances of 1.88 and 1.84 A, respectively. The geometry around Ru in trans-[RuL(NO)Cl] is octahedral with Ru–N (nitrosyl) and Ru–Cl distances of 1.72(2) and 2.354(4)A, respectively, and Ru–N–O 175(2)°. The cyclic voltammograms for the metal Schiff-base complexes show reversible MIII–MII and ligand-centred oxidation couples. Treatment of NiL with AgBF4 afforded air-stable [NiL]BF4, which is formulated as a nickel(II) complex of the Schiff-base cation radical.

Ruthenium thiocarbonyl and phosphoniodithiocarboxylate complexes with an oxygen tripod ligand

Abstract Treatment of [Ru(CO)2Cl2]x with NaLOEt (LOEt−=[Co(η5-C5H5){P(O)(OEt)2}3]−) afforded [LOEtRu(CO)2Cl] (1), which reacted with AgBF4 in acetone–H2O to give [LOEtRu(CO)2(H2O)][BF4] (2). Reaction of [LOEtRu(CHCHPh)(CO)(PPh3)] with HCl gave [LOEtRuCl(CO)(PPh3)] (3), which has been characterized by X-ray crystallography. The RuC, RuP, RuCl and average RuO distances in 3 are 1.993(7), 2.2811(13), 2.376(2) and 2.137 A, respectively. Interaction of [LOEtRu(PPh3)2Cl] with CS2 and PR3 in the presence of [NH4][PF6] afforded the ruthenium(II) phosphoniodithiocarboxylate species [LOEtRu(PPh3)(η2-S2CPR3)][PF6] (R=Ph (4) or cyclohexyl (5)). Oxidation of 4 with AgBF4 yielded the ruthenium(III) complex [LOEtRu(PPh3)(η2-S2CPPh3)][BF4][PF6] (6), which has been characterized by X-ray crystallography. The RuP, average RuO and average RuS distances in 6 are 2.3978(10), 2.078 and 2.2910 A, respectively. The ruthenium(II) thiocarbonyl complex [LOEtRu(CS)Cl(PPh3)] (7) was prepared from NaLOEt and [Ru(CS)Cl2(PPh3)2]2. The RuCl, RuP, RuC and average RuO distances in 7 are 2.3681(10), 2.3043(9), 1.823(4), and 2.140 A, respectively. Treatment of 7 with AgBF4 in acetone–H2O afforded [LOEtRu(CS)(PPh3)(H2O)][BF4] (8). On the basis of the Ru(III/II) formal potential, CS was found to be a stronger π acid ligand than CO.

Dichloro[(1R,2R)-N-(2-pyridylmethylene)-1,2-cyclohexanediamine]copper(II)

The crystal structure of [CuCl 2 (C 12 H 17 N 3 )], containing a five-coordinate Cu II atom with distorted trigonal-bipyramidal coordination, is reported. The absolute configuration (1R,2R) has been verified.