STEREOCHEMISTRY OF COMPLEXES WITH N-ALKYLATED AMINO ACIDS. VII. CRYSTAL STRUCTURE OF BIS(N-tert-BUTYL-N-BENZYLGLYCINATO)COPPER(II). CONFORMATIONAL ANALYSIS AND MOLECULAR MECHANICS CALCULATIONS

The structure of the red, monoclinic modification of bis(N-tert−butyl-N−benzylglycynato)copper(II) was solved by X-ray diffraction analysis and refined to R = 0.044. The structure is made up of discrete molecules with the copper atom (situated at an inversion centre) having square-planar coordination with oxygen and nitrogen atoms in trans positions with Cu-O 187.4(2) and Cu-N 2.112(3)Å. The results of molecular mechanics calculations reveal that the crystal conformation has about 13 kJ mol−1 higher energy than the lowest energy conformation. This suggests the influence of intra- and intermolecular interactions in defining the molecular conformation.