Stereochemistry of complexes with n‐alkylated amino acids. xii. crystal structure and molecular mechanics calculations for aqu abis(l‐n, n‐dimethylalaninato)copper(ii) hexahydrate

Abstract

The structure of blue, monoclinic (C2) crystals of trans-aquabis(L-N, N-dimethylalaninato-)copper(II) hexahydrate was determined by X-ray diffraction methods and refined to R = 0.026. The structure consists of discrete molecules in the same (equatorial-equatorial) conformation linked together in a comprehensive array of water molecules with the structure resembling that of ice. The copper coordination polyhedron is highly distorted [N-Cu-N′ = 166.2(1)° and O-Cu-O′ 161.5(1)°] and the apical bond length [Cu-OW = 2.222(3) Å] is extremely short, which is a direct consequence of the distortion of the coordination polyhedron. Conformational analysis shows that the conformation of the molecule in the crystal state is 1.4 kJ mol−1 higher in energy than the most stable conformer (with axial-axial conformation).