Studies on the metalamide bond. VI. The crystal structure of aqua[N,N′-bis(2′-pyridinecarboxamido)-cis-1,2-cyclohexane] copper(II) monohydrate

Aqual[N,N′-bis(2′-pyridinecarboxamido)-cis-1,2-cyclohexane] copper(II) monohydrate, C₁₈H₂₂N₄O₄Cu, is monoclinic, space group C2/c, with a = 19.985(8), b = 11.114(3), c = 17.581(5) Å, β = 112.5(1)°, Z = 8. The structure was refined to R = 0.082 for 2224 photographic reflexions by full-matrix least-squares calculations. The copper atom is five-coordinate wih the N₄-tetradentate ligand encompassing the base of a distorted square-based pyramid [average CuN(amide) 1.933(8); CuN (pyridine) 2.027(7) Å, N(amide)CuN(amide) 83.2(3)°, N(pyridine)CuN(pyridine) 111.0(3)°] and with the Cu atom lying 0.19 Å above the N₄ plane towards the apical waterr molecule [CuO 2.382(7) Å]. Both amide nitrogen atoms show approximately 35% pyramidal distortion. The cyclohexane ring adopts a chair conformation with the two methine hydrogen atoms in a cis-conformation. The molecules pack in sheets parallel to(101) and a hydrogen-bond network involves both water molecules and the amide oxygen atoms of the ligand.