On the electronic coupling of the C=O stretching vibrations in Cl(2)Pt(malonate)(-).
Ab initio calculations on the complex Cl(2)Pt(malonate)(-) have been performed to estimate the magnitude and the source of the splitting between the symmetric and antisymmetric C=O stretches. It is shown that a large part of the splitting can result from pure electronic coupling mediated via the pi-structure of the ligand. Calculations have also been performed on the free ligand malonate(-) and the neutral malonaldehyde that show decreasing electronic coupling, which is consistent with the decreasing resonance stabilization. A simple effective C=O interaction potential has been produced for Cl(2)Pt(malonate)(-) that is used to estimate the electronic splitting of the 1600 cm(-1) IR band to 137 cm(-1). Anharmonic contributions seem to reduce this value somewhat, but the magnitude and sign of the splitting is similar to the experimental value of 183 cm(-1) found for the similar Cl(2)Pt(acac)(-) complex.
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Departamento de Química Física, Universitat de València, Dr. Moliner 50, Burjassot, E-46100 Valencia, Spain.
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