Synthesis and Characterization of Mononuclear andBinuclear Metal Complexes of a New Fluorescent Dye Derived from 2-Hydroxy-1-Naphthaldehyde and 7-Amino-4-Methylcoumarin

A mononuclear cu(ii), zn(ii) and binuclear cu(ii) complexes derived from the reactions of cu(acac)2, zn(oac)2.2h2o and cu(oac)2.h2o respectively with the monobasic, bidentate and fluorescent schiff base ligand [7-{(2-hydroxynaphthalen-1-yl)methylidene]amino}-4-methyl-2h-chromen-2-one, hl] have been synthesized. the ligand and its metal complexes were characterized by microanalytical, mass, ir, uv-vis, esr, fluorescence, h- and c-nmr studies. the fluorescent hl consists of a methyl substituted coumarin group fused to a 2-hydroxynaphthaenyl ring via an azomethine linkage. the ligand acts as a bidentate, through no in coordinating to the m(ii) ions. the two bonding sites are the azomethine nitrogen and naphthanolic oxygen. microanalytical and mass analyses are consistent with the formation of mono-and binuclear complexes. spectral studies indicate a square planar structure for the monnouclear [cu(l)(acac)] complex, while the binuclear cu(ii) and mononuclear zn(ii) complexes exist as [{cu(l)2}2] and [zn(l)(hl)(oac)] respectively having penta-coordinate geometry. the esr spectrum of [{cu(l)2}2] in dmso further confirm that the ground state is dz^2 and the complex has a trigonal bipyramidal geometry around the cu(ii) centers.