Synthesis, spectroscopic, redox, catalytic and antimicrobial properties of some ruthenium(II) Schiff base complexes

Abstract

A new series of mixed ligand semicarbazone or thiosemicarbazone complexes of Ru(II) having the general formula [RuCO(EPh 3 )(B)L] (where E = P or As; B = PPh 3 , AsPh 3 or Pyridine; L = dibasic tridentate ligand derived by the condensation of ethylacetoacetate/methylacetoacetate and thiosemicarbazide/semicarbazide) have been synthesized and characterized by physico-chemical, spectroscopic and electrochemical studies. A comparative study on the catalysis of oxidation of benzyl alcohol, cyclohexanol, cinnamyl alcohol, n-butanol, n-propanol and iso-butyl alcohol has been done with N-methylmorpholine-N-oxide and molecular oxygen as co-oxidants. Catalytic activity studies of the complexes in coupling reactions have been carried out. The antibacterial properties of the complexes have also been examined.

Synthesis, spectral characterization, CC coupling, oxidation reactions and antibacterial activities of new ruthenium(III) Schiff base complexes

“…The remaining PhBr in Et 2 O (5 cm 3 ) was added dropwise and the mixture was refluxed for 40 min. To this mixture, 1.03 cm 3 (0.01 mol) of PhBr in anhydrous Et 2 O (5 cm 3 ) and the Ru(III) Schiff base complex (0.05 mmol) chosen for investigation were added and heated under reflux for 6 h. The reaction mixture was cooled and hydrolyzed with a saturated solution of aqueous NH 4 Cl and the ether extract on evaporation gave a crude product, which was chromatographed to obtain pure biphenyl and compared well with an authentic sample 27–32, 36, 37…”

“…To a solution of alcohol (1 mmol) in CH 2 Cl 2 (20 cm 3 ), a solution of the ruthenium complex in CH 2 Cl 2 (0.01 mmol) was added and the mixture was stirred under an oxygen atmosphere at ambient temperature for 6 h and the solvent was then evaporated from the mother liquor under reduced pressure. The resulting carbonyl compounds was then extracted with petroleum ether (60–80 °C; 20 cm 3 ) and was then quantified as 2, 4‐dinitrophenylhydrazone derivative 27–32. The oxidation products are known and are commercially available.…”

“…Therefore, systematic studies that selectively change the structural and electronic features in ruthenium complexes and modulate their effect on catalytic properties could help to clarify the reactivity of those metal centers toward alcohol oxidation and coupling reactions. In connection with our ongoing interest in this field of research, we have already investigated several ruthenium (II) and ruthenium (III) complexes 27–32. Herein, we describe the synthesis and characterization of a series of new class of ruthenium(III) Schiff base complexes along with their catalytic activity towards the selective oxidation of alcohols in the presence of O 2 atmosphere at ambient temperature, NMO and H 2 O 2 as co‐oxidants and CC coupling reactions.…”

Thiosemicarbazone Complexes of Transition Metals as Catalysts for Cross-Coupling Reactions

“…This versatility of coordination, together with the relative ease with which these ligands can often be prepared, has provided a considerable impetus into the study of their metal complexes, and particularly how it can be exploited for the development of new catalysts. Reactions which have been studied using these systems include oxidation [58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74], transfer hydrogenation [75][76][77], reduction [14], silane alcoholysis [12,13,78], condensation reactions [79][80][81], and the cyclopropanation of olefins [82,83], as well as coupling reactions which are described here. Some of these have also previously been covered by Kumar et al in reviews of the role of organochalcogen ligands in Mizoroki-Heck Scheme 1.…”

Photophysical properties and computational study of newly synthesized lanthanide complexes with N-(2-carboxyphenyl)salicylideneimine Schiff base ligand

“…Ni} [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. A variety of coordination modes were proposed depending on reaction conditions, nature of the metal and stability of the complex formed [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. The coordination behavior of LH 2 ligand towards Ln(III) ions will be investigated via elemental analysis, spectroscopic analysis (UV-Visible, FTIR, 1 H and 13 C NMR), molar conductance and thermal analysis.…”