A new potential NLO compound with a supramolecular layered structure: aqua(hexamethylenetetramine-κN)(iminodiacetato-κ3O,N,O')copper(II).

In the noncentrosymmetric title compound, [Cu(C(4)H(5)NO(4))(C(6)H(12)N(4))(H(2)O)] or [Cu(IDA)(HMTA)(H(2)O)], where IDA is iminodiacetate and HMTA is hexamethylenetetramine, the asymmetric unit consists of a whole mononuclear neutral molecule, where the Cu(II) cation is coordinated by two carboxylate O atoms and one N atom from the IDA ligand, by one N atom from the HMTA ligand and by the O atom of the coordinated water molecule, giving rise to a CuN(2)O(3) distorted square-pyramidal coordination geometry. The IDA and HTMA ligands adopt terminal tri- and monocoordinated modes, respectively. All adjacent molecules within the ac plane are connected to each other via two pairs of O-H···O and one N-H...O hydrogen bond, forming a (4,4) supramolecular two-dimensional network. In the unit cell, these layers stack alternately in an …ABABAB… sequence along the b axis. The optical absorption properties of this compound have been studied on powder samples, which had previously been examined by powder X-ray diffraction.