A new end-off type acyclic ligand with four methoxyethyl chelating arms, 2,6-bis[bis(2-methoxyethyl)aminomethyl]-4-methylphenol (Hbomp), formed a dinuclear zinc(II) complex [Zn2(bomp)(MeCO2)2]BPh4 1. X-Ray analysis revealed that the complex 1·CHCl3 contains two zinc ions bridged by the phenolic oxygen and two acetate groups, forming a µ-phenoxo-bis(µ-acetato)dizinc(II) core. The aminopeptidase function of complex 1 was estimated using N-p-nitrophenyl-L-leucine as substrate. The release of p-nitroaniline as the result of the substrate hydrolysis is first order in both complex and substrate concentrations with k = 2.3(1) × 10–3 dm3 mol–1 s–1.
1 April 2004 in Journal of Organometallic Chemistry
A tetrahedrally distorted mononuclear copper(II) complex, [Cu(salabza)] 1, and two dinuclear CuLn complexes, [Cu(salabza)Ln(hfac)3] (Ln = Gd 2 or Lu 3), were synthesized and their molecular structures determined, where H2salabza and Hhfac denote N,N′-bis(salicylidene)-2-aminobenzylamine and 1,1,1,5,5,5-hexafluoroacetylacetone, respectively. In complex 1 the deviations of the four co-ordinating atoms (O(1), O(2), N(1) and N(2)) of salabza2− and the copper atom from the least-squares equatorial plane O(1)O(2)N(1)N(2) indicate the tetrahedral distortion around Cu. In 2 and 3 the CuII and LnIII are bridged by the two phenolic oxygens of salabza2−. The Cu⋯Ln distances are 3.2481(8) Å for 2 and 3.1825(7) Å for 3. The structures of 2 and 3 were found to consist of a perfectly discrete dinuclear CuLn unit, the shortest intermolecular Cu⋯Cu, Cu⋯Ln and Ln⋯Ln distances being 6.002(1), 7.522(1) and 8.507(1) Å for 2, and 5.998(1), 7.509(1) and 8.584(1) Å for 3, respectively. Cryomagnetic susceptibility measurements of 2 in the region of 2 K to room temperature indicated the operation of a ferromagnetic interaction between CuII and GdIII, with J = +0.8 cm−1 based on H = −2JSCu·SGd. This was confirmed by measurements of the field dependence of magnetization at 2 K.