Syntheses and X-ray crystal structures of five- and six-coordinate copper(II) complexes of N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides containing–OClO3 and–OSO2CF3 counter ions

Reactions of anhydrous copper(II) chloride with NaX (1 : 1 or 1 : 2) and AgX (1 : 2) containing appropriate N,N,N′,N′-tetraalkylpyridine-2,6-dicarboxamides(O-daap) in CH3CN yield monosubstituted five-coordinate [Cu(L1)Cl(CF3SO3)] (1), [Cu(L2)Cl(ClO4)] (2), [Cu(L3)Cl(ClO4)] (3), and six-coordinate [Cu(L2)(CF3SO3)2] · H2O (4) (X = −OClO3 and–OSO2CF3; L1 = N,N,N′,N′-tetraethylpyridine-2,6-dicarboxamides; L2 = N,N,N′,N′-tetraisopropylpyridine-2,6-dicarboxamides; L3 = N,N,N′,N′-tetraisobutylpyridine-2,6-dicarboxamides). The structures of these complexes have been determined by X-ray crystallography. The Cu2+ in 1–3 adopts distorted square-pyramidal geometry, while 4 exhibits octahedral structure. Steric factors in conjunction with lattice effects and the nature of the anions are responsible for the variety in coordination spheres. These compounds undergo extensive intermolecular H-bonding to give to 2-D sheets extending along various planes.