Anion directed template synthesis of Cu(II) complexes of a N,N,O donor mono-condensed Schiff base ligand: A molecular scaffold forming highly ordered H-bonded rectangular grids

摘要

Anion directed, template syntheses of two dinuclear copper(Il) complexes of mono-condensed Schiff base ligand Hdipn (4-[(3-aminopentylimino)-methyl]-benzene-1,3-diol) involving 2,4-dihydroxybenzalde_hyde and 1,3-diaminopentane were realized in the presence of bridging azide and acetate anions. Both complexes, [Cu_2(dipn)_2(N_3)_2] (1) and [Cu_2(dipn)_2(OAc)_2] (2) have been characterized by X-ray crystallography. The two mononuclear units are joined together by basal-apical, double end-on azido bridges in complex 1 and by basal-apical, double mono-atomic acetate oxygen-bridges in 2. Both complexes form rectangular grid-like supramolecular structures via H-bonds connecting the azide or acetate anion and the p-hydroxy group of 2,4-dihydroxybenzaldehyde. Variable-temperature (300-2 K) magnetic suscepti_bility measurements reveal that complex 1 has antiferromagnetic coupling U = -2.10 cm~(-1)) through the azide bridge while 2 has intra-dimer ferromagnetic coupling through the acetate bridge and inter-dimer antiferromagnetic coupling through H-bonds U = 2.85 cm~(-1),1 = -1.08 cm~(-1)).