Ru(II)–halide–carbonyl complexes of naphthylazoimidazoles: Synthesis, spectra, electrochemistry, catalytic activity and electronic structure
作者:Shyamal Kumar Sarkar、Mahendra Sekhar Jana、Tapan Kumar Mondal、Chittaranjan Sinha
DOI:10.1016/j.jorganchem.2012.06.009
日期:2012.10
[Ru(CO)(2)Cl-2(alpha/beta-NaiR)] (1, 2) and [Ru(CO)(2)I-2(alpha/beta-NaiR)] (3, 4) are synthesized by the reaction of [Ru(CO)(2)Cl-2](n) or [Ru(CO)(4)I-2] with alpha/beta-NaiR (1-alkyl-2-(naphthyl-alpha/beta-azo)imidazole (alpha-NaiR/beta-NaiR, where, R = Me, CH2CH3 and CH2Ph)) and have been characterized by spectroscopic data. The geometry of the representative complexes [Ru(CO)(2)Cl-2(beta-NaiMe)] (2a) and [Ru(CO)(2)I-2(beta-NaiEt)] (4b) have been structurally confirmed by X-ray diffraction study. The redox property is examined by electrochemistry. Catalytic activity of these compounds is investigated to the oxidation of PhCH2OH to PhCHO, 2-butanol (C4H9OH) to 2-butanone, 1-phenylethanol (PhC2H4OH) to acetophenone, cyclopentanol (C5H9OH) to cyclopentanone and cyclohexanol to cyclohexanone by N-methylmorpholine-N-oxide (NMO), H2O2 or (BuOOH)-O-t in CH2Cl2 and NMO shows highest yield. The catalytic efficiency is again dependent on Ru-X (X = Cl or I) bond and higher yield is observed for [Ru(CO)(2)Cl-2(alpha/beta-NaiR)] (1, 2). Electronic structure, spectral and redox properties are explained based on DFT and TD-DFT calculations on the representative complexes. (C) 2012 Elsevier B.V. All rights reserved.