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In this work, four new ruthenium complexes [Ru(η 6 - p -cymene)(L1)Cl] 1, [Ru(η 6 - p -cymene)(L2)Cl] 2, [Ru(η 6 - p -cymene)(L3)Cl] 3 and [Ru(η 6 - p -cymene)(L4)Cl] 4 [HL1 = (2-cyanophenyl)glycine; HL2 = (5-chloro-2-cyanophenyl)glycine; HL3 = (2-cyano-3-fluorophenyl)glycine; HL4 = (4-cyanophenyl)glycine] were synthesized and well characterized by several spectroscopic and analytical techniques. Complexes 1 and 3 were found to be fluorescent in most of the solvents; however, 2 and 4 were found to be fluorescent mostly in EtOAc, DMF and ethanol. Amongst these four complexes, 3 has shown selective sensing against CO 3 2- and SO 4 2- anions by quenching of fluorescence. The LOD values are found to be in the sub-micromolar range. Investigations of the sensing mechanism performed by computation and NMR studies indicate a possible adduct formation between the NH group of the ligand and the anion(s) through hydrogen bond formation, which ultimately might lead to proton transfer to the bi-negative anion. The quantum yield of the complex 3 was found to decrease on addition of CO 3 2- and SO 4 2- anions from 0.46 to 0.13 and 0.12, respectively. The Job's plot indicates the binding between the probe and anion in a 1 : 1 ratio for both CO 3 2- and SO 4 2- anions. Along with that, all the complexes were found to be biocompatible when tested against several cell lines showing very high IC 50 values. It can also be observed that 1 is capable of penetrating within the cells and can act as a cell imaging agent showing fluorescence, and thus can be used for bio-imaging purposes.

Four new ruthenium arene PTA type complexes have been synthesized using substituted picolinamide derivatives as ancillary ligands and characterized by spectroscopic methods. In one of the complexes, the ancillary ligand has shown an unprecedented valence-bond tautomerization in the presence of an ammonium salt to act as a polar neutral donor ligand making the ligand more prone towards substitution. The same compound has shown remarkable antiproliferative activity against three cancer cell lines with GI 50 values comparable to Adriamycin, a known therapeutic drug. Along with this it also strongly inhibits the action of thioredoxin reductase, which might be a probable reason for the enhanced proliferative action of the valence-bond tautomerized compound.

In this work, four new ruthenium complexes [Ru(η6-p-cymene)(L1)Cl] 1, [Ru(η6-p-cymene)(L2)Cl] 2, [Ru(η6-p-cymene)(L3)Cl] 3 and [Ru(η6-p-cymene)(L4)Cl] 4 [HL1 = (2-cyanophenyl)glycine; HL2 = (5-chloro-2-cyanophenyl)glycine; HL3 = (2-cyano-3-fluorophenyl)glycine; HL4 = (4-cyanophenyl)glycine] were synthesized and well characterized by several spectroscopic and analytical techniques. Complexes 1 and 3 were found to be fluorescent in most of the solvents; however, 2 and 4 were found to be fluorescent mostly in EtOAc, DMF and ethanol. Amongst these four complexes, 3 has shown selective sensing against CO32− and SO42− anions by quenching of fluorescence. The LOD values are found to be in the sub-micromolar range. Investigations of the sensing mechanism performed by computation and NMR studies indicate a possible adduct formation between the NH group of the ligand and the anion(s) through hydrogen bond formation, which ultimately might lead to proton transfer to the bi-negative anion. The quantum yield of the complex 3 was found to decrease on addition of CO32− and SO42− anions from 0.46 to 0.13 and 0.12, respectively. The Job's plot indicates the binding between the probe and anion in a 1 : 1 ratio for both CO32− and SO42− anions. Along with that, all the complexes were found to be biocompatible when tested against several cell lines showing very high IC50 values. It can also be observed that 1 is capable of penetrating within the cells and can act as a cell imaging agent showing fluorescence, and thus can be used for bio-imaging purposes. [ABSTRACT FROM AUTHOR]

Four new ruthenium arene PTA type complexes have been synthesized using substituted picolinamide derivatives as ancillary ligands and characterized by spectroscopic methods. In one of the complexes, the ancillary ligand has shown an unprecedented valence-bond tautomerization in the presence of an ammonium salt to act as a polar neutral donor ligand making the ligand more prone towards substitution. The same compound has shown remarkable antiproliferative activity against three cancer cell lines with GI50 values comparable to Adriamycin, a known therapeutic drug. Along with this it also strongly inhibits the action of thioredoxin reductase, which might be a probable reason for the enhanced proliferative action of the valence-bond tautomerized compound. [ABSTRACT FROM AUTHOR]