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The synthesis of mononuclear copper complexes has been stimulated by a desire to "mimic" the active sites of metalloproteins, such as the enzyme galactose oxidase and nitrite reductase. A systematic study of various copper(II) complexes indicates that the redox and magnetic properties of these complexes are strongly influenced by the ligand characteristics, such as the nature of the donor atoms, the stereochemistry around the copper atoms, and substituents present in the ligands. Hence the synthesis of different nucleating ligands, which can induce dissimilarities both in structural electronic aspects, and a comparison to understand the role of the ligand characteristic on these properties have been carried out. The geometry of the coordination polyhedron around copper(II) is also influenced by several subtle ligand factors, such as ligand constraints, steric hindrance and the ligands' donor atoms' strengths. The present study aims to bring out the structural and conformational features of the mononuclear copper(II) complex, 4-chloro-3-methyl-6(3′-N,Ndimethylamino-1′-iminomethyl)phenolatocopper(II) acetate, by using crystallographic methods.The ligand of the title complex, 4-chloro-3-methyl-6(3′-N,Ndimethylamino-1′-iminomethyl)phenol, was prepared by reacting equimolar quantity of 4-chloro-3-methyl salicylaldehyde (0.05 mol) and 3-(N,N-dimethyl)amino propylamine (0.05 mol) at room temperature. A separated crystalline solid was washed with methanol and recrystallized in ethanol. The above ligand (0.02 mol) and copper(II) acetate (0.02 mol) were dissolved in 100 ml of ethanol and refluxed for 1 h. The resulting solution was evaporated at room temperature. Separated green crystals were washed, filtered and dried.The structure was solved by the Patterson method, and refined on F 2 by full-matrix least-squares procedures. A few hydrogen atoms were identified in a difference Fourier map, and the rest were fixed as a riding model over their heavier atoms. While refining it, a rotational disorder for the atom C16 (methyl group) has been observed and the disordered positions have an occupancy of 50%. The crystal data and the other relevant parameters are given in Table 1. The atomic coordinates along with their equivalent isotropic displacement factors for non-

The title compound crystallizes in monoclinic space group C2/c with cell parameters a = 21.404(2), b = 13.962(1), c = 17.917(1)Å, β = 124.394(2)°, V = 4418.3(6)Å 3 , Z = 8, D cal = 1.193Mg/m 3 and T = 293 K. The structure was solved by Patterson method and refined by full-matrix least-squares procedures to final R = 0.0882 using 5253 observed reflections. The tetra coordinated copper atom have a slight distorted square planar geometry with the Cu-Cu distance of 2.987(1)Å. The two six membered rings containing copper atom assume distorted sofa conformation. C -H…π and C -H…O type of intermolecular interactions play a role in stabilizing the crystal packing in addition to van der Waals forces.

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