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

Abstract

Aqual[N,N′-bis(2′-pyridinecarboxamido)- cis-1,2-cyclohexane] copper(II) monohydrate, C 18H 22N 4O 4Cu, 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 N 4-tetradentate ligand encompassing the base of a distorted square-based pyramid [average CuN( amide) 1.933(8); CuN ( pyridine) 2.027(7) Å, N( amide)CuN( amide) 83.2(3)°, N( pyridine)CuN( pyridine) 111.0(3)°] and with the Cu atom lying 0.19 Å above the N 4 plane towards the apical waterr molecule [CuO 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(10 1 ) and a hydrogen-bond network involves both water molecules and the amide oxygen atoms of the ligand.