69063-76-9Relevant articles and documents
Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum(V) tetraphenylporphyrin in chlorinated solvents
Douvas, Antonios M.,Argitis, Panagiotis,Maldotti, Andrea,Coutsolelos, Athanassios G.
, p. 3427 - 3434 (2008/10/09)
Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum(V) 5,10,15,20-tetraphenylporphyrin, Mo(V)O(TPP)OEt, under irradiation at the Soret band region, were investigated. The reactions were performed in chlorinated solvents and followed with ultraviolet-visible (UV-vis) spectroscopy, whereas the products were analyzed with Fourier transformed infrared (FTIR) spectroscopy, electron spin resonance (ESR) spectroscopy and gas chromatography (GC). The chloro-oxo(TPP)Mo(V) complex was obtained as the final product, where the chlorine came from the solvent. Nevertheless, these reactions were not photocatalytic, due to the photochemical inertness of the formed chloro-oxo complex, and an excess of ethanol could not initiate a new photocatalytic cycle unless water was added as well, resulting in the formation of a biphasic system. On the other hand, addition of ethanol, water and NaOH to the reaction medium led to the formation of the corresponding oxo Mo(IV) complex. The studied photoassisted reactions of oxo Mo(V) porphyrins appear attractive for possible applications in the detection of chlorinated pollutants in sensing devices, but also for the dechlorination of pollutants upon suitable optimization of processing conditions.
Transition-metal complexes of pyrrole pigments. 18. Redox behaviors of oxomolybdenum(V) complexes formed with macrocyclic tetrapyrroles
Matsuda, Yoshihisa,Yamada, Sunao,Murakami, Yukito
, p. 2239 - 2246 (2008/10/08)
The redox chemistry of (2,3,17,18-tetramethyl-7,8,12,13-tetraethylcorrolato)oxomolybdenum(V) [Mo(O)(MEC)] and (5,10,15,20-tetraphenylporphinato)oxomolybdenum(V) complexes [Mo(O)(TPP)(X), X = MeO, AcO, and Cl] was investigated in dichloromethane by means of cyclic voltammetry and controlled-potential electrolysis. One-electron oxidation and reduction of Mo(O)(MEC) at MoV were observed at +0.70 and -0.72 V vs. SCE, respectively. Such oxidation and reduction potentials for Mo(O)(TPP)(X) were very dependent on the nature of axial ligand X and consequently on the covalent character of the MoV-X bond: one-electron reduction becomes less facile as the covalent character increases and reaches the value of that in Mo(O)(MEC) for X = MeO. The TPP complexes were much more resistant to oxidation of MoV than the MEC complex. Two successive reductions of TPP were observed for Mo(O)(TPP)(X) at -1.1 and -1.5 V vs. SCE while no ligand reduction was detected for Mo(O)(MEC) in the cathodic region up to -2.0 V vs. SCE. On the basis of complete redox schemes for Mo(O)(MEC) and Mo(O)(TPP)(X), correlations between redox properties and ligand structures have been discussed. Coordination equilibria for reactions of Mo(O)(TPP)(MeO) with AcO-, Cl-, and ClO4- were investigated in dichloromethane, and the chloro complex was found to exist as a dimer while the others are monomers in solution.
