Synthesis and X-ray structure of tetrakis[μ-(3,4-dimethoxy-α-β-dihydrocinnamato)] dimethanoldicopper(II)

The synthesis, magnetic, and structural properties of the title compound are reported. The crystals are triclinic, space group P-1, with a=15.084(2), b=11.820(1), c=7.5253(7) Å, α=71.50(1), β=77.61(1), γ=68.68(1)° and Z=1; the structure was solved by Patterson and Fourier methods and refined to R 0.0351 for 4147 observed reflections. The content of the unit cell consists of a centrosymmetrical copper acetate-like molecule in which each copper can be described as square-pyramidally surrounded by four carboxylic oxygens in the basal plane [1.955(2)-1.970(2) Å], one methanolic oxygen in the apical site [2.206(2) Å] and a Cu⋯Cu interaction of 2.612(5) Å at a sixth position of a distorted octahedron. The dimers are packed by means of hydrogen bonds formed between the methanolic OH group and the carboxylic O(2) atom of one adjacent complex and by normal Van der Waals contacts. The subnormal magnetic moment, characteristic of exchange interactions between the two copper(II) ions, and the energy of the d-d band observed are consistent with the reported dinuclear copper(II) acetate-like structure. © 1990 Plenum Publishing Corporation.