The UV-Vis spectra and substituent effect of organoimido derivatives of polyoxometalates

In the presence of a carbodiimine, i. e. DCC, a series of organoimido derivatives of polyoxometalates have been synthesized via the reaction of [ alpha-Mo-8 O-26 ](4-) with aromatic amines and its hydrochloride salt. Elemental analysis, IR, H-1-NMR and UV-Vis spectra were used to characterize those hybrids, in particular their UV-Vis spectra have been studied. The results show that typical metal-ligand charge transfer (MLCT) transitions occur in the organic- inorganic hybrid molecules. There is a good linear relationship between the shift of UV-Vis absorptions(Delta lambda(max)) and conjugation effect of the p-substituted group (sigma(R)).