Four new mixed ligand transition metal (Co(II), Ni(II), Cu(II) and Zn(II)) complexes of p-coumaric acid and coumarine have been
synthesized and the structurally characterized. These complexes contain hydrate water except the Cu(II) complex. Coumaric acid is a
monodendate ligand except Cu(II)-complex in which a bidendate coordination mode could be observed. The thermal decomposition starts
with dehydration of Co(II), Ni(II) and Zn(II) complexes while in Cu(II) complex decomposition starts with fragmentation of organic
ligands at 145 °C. Studies on their biological activity have also been performed. Molecular formulas of the obtained complex are as
follows: (I) [Co(C9H7O3)2(C9H6O2)2(H2O)2]
.
4H2O; (II) [Ni(C9H7O3)2(C9H6O2)2(H2O)2]
.
6H2O; (III) [Cu(C9H7O3)2(C9H6O2)2]
and (IV) [Zn(C9H7O3)2(C9H6O2)2(H2O)2]
.
3H2O. The ratio of metal: p-coumaric acid: coumarin in complexes are found to be 1:2:2.
The complex IV is diamagnetic, and the other complexes are paramagnetic. According to BM data and result of electronic spectra, the
geometry for all of the complexes has thought to be octahedral coordination around the metal ions.
Key words: Biological activity, coumarin, mixed ligand, coumaric acid, metal complexes, spectroscopic methods.
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