Absorption Spectra of New Oxomolybdenum(V) Complexes of Tetraphenylporphyrin with Univalent Ligands

Article abstract of DOI:10.1246/bcsj.54.170

New tetraphenylporphyrin complexes, MoO(tpp)X (X = F, Br, BF4, NCO, N3, and NCS), are easily prepared from the complex, MoO(tpp)OC2H5, where TPP denotes meso-tetraphenylporphyrin.The complexes are confirmed to contain a central oxomolybdenum(V) group based on the IR and the ESR measurements.The visible absorption spectra of the complexes in dichloromethane have three main peaks, the Soret band, the α and the β bands.The degree of red shifts of the corresponding absorption maxima is found to increase in the order: X = OC2H5 less than BF4 ca.F less than NCO less than N3 less than NCS less than Cl less than Br, accompanied with the same order of the change in the ratio ε_α/ε_β.The correlation is also observed between the red shifts of the absorption peak around 330 nm and those of the Soret band.The complexes, MoO(tpp)X, are classified to d-type hyperporphyrin.