Syntheses, structural characterizations and electronic absorption spectra simulation of three phenylimido substituted hexamolybdates incorporating a remote chloro group

Three monofunctionalized organoimido derivatives of [Mo₆O₁₉]²⁻ bearing an electron-withdrawing chloro group (R = p-ClC₆H₄1, m-ClC₆H₄2, or o-ClC₆H₄3) have been prepared in high purity and moderate to good yields using an easy reaction route of [α-Mo₈O₂₆]⁴⁻ with corresponding aromatic amine hydrochlorides or a mixture of aromatic amines and their hydrochloride salts in the presence of N,N′-dicyclohexylcarbodiimide (DCC). These complexes have been characterized by ¹H NMR, IR, UV-Vis, UV-Vis-NIR reflectance spectroscopy, cyclic voltammetry, and their semiconductive and redox properties were explored by these techniques. Their electronic absorption spectra were also interpreted based on first-principles electronic structure calculations and these features of the simulated spectra are qualitatively consistent with the observed UV spectra. Additionally, the composition and structure of compounds 1 and 2 were further confirmed by X-ray single-crystal diffraction studies.