(IUCr) Crystallography Journals Online

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Acta Cryst. (2002). E58, m217-m219 [ doi:10.1107/S1600536802007092 ]

Bis(1,1-dimethylbiguanido)copper(II) octahydrate

M. Zhu, L. Lu, P. Yang and X. Jin

Abstract: A complex of a deprotonated form of metformin with Cu²⁺, [Cu(C₄H₁₀N₅)₂]·8H₂O, was prepared from alkaline aqueous solution. The coordination geometry around the Cu atom is square planar, with four N atoms from two bidentate ligands. The deprotonation of the ligand causes an increase in the [pi] conjugation of the C-N-C system, reducing the bond angle at the central N atom to nearly 120°. The dihedral angle between the two six-membered chelate rings in the complex is 11.31 (5)°. The Cu atom lies on a twofold rotation axis.

Online 25 April 2002