Studies on the synthesis, spectra, catalytic and antibacterial activities of binuclear ruthenium(II) complexes

A new series of stable binuclear ruthenium(II) carbonyl complexes of the general formula [{RuX(CO)(EPh3)2}2L] (where X = H or Cl; E = P or As and L = dibasic tetradentate diacetyl resorcinol (H2-DAR)) have been synthesised by reacting ruthenium(II) starting complexes [RuHX(CO)(EPh3)3] (where X = H or Cl; E = P or As) and 4,6-diacetylresorcinol (H2-DAR) ligand in benzene medium. The structure of the new binuclear ruthenium(II) carbonyl complexes was established using elemental analysis, spectra (FT-IR, UV-vis and 1H NMR), electrochemical and thermal studies. In these reactions, the 4,6-diacetylresorcinol (H2-DAR) ligand behaves as a binegative tetradentate chelating ligand coordinating through O,O atoms of both the carbonyl and phenolic C-O groups by replacing a molecule of PPh3/AsPh3 and a hydride ion from the starting complexes. Further, all these complexes were also employed as new catalysts for the oxidation of primary and secondary alcohols in the presence of N-methylmorpholine-N-oxide (NMO) as a more viable co-oxidant. The free ligand and their metal complexes have also been screened for their antibacterial activity against the growth of gram +ve and gram −ve bacterial cultures.