Recognition and mechanistic investigation of anion sensing by ruthenium(ii) arene complexes and bio-imaging application. Issue 34 (16th August 2022)

• Record Type: Journal Article
• Authors: Sonkar, Chanchal; Sarkar, Sayantan; Malviya, Novina; Kuznetsov, Maxim L.; Mukhopadhyay, Suman
• Is Part Of: Dalton transactions. Volume 51:Issue 34(2022)
• Page Start: 13071
• Page End: 13084
• Publication Date: 2022-08-16
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt01726a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Four new ruthenium(ii )–arene amino acid complexes were synthesised and characterized by spectrophotometric, analytical and computational techniques. Further evaluation for their sensing, bio-compatibility, and bio-imaging abilities were carried out. Abstract : 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 CO3 2− and SO4 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 CO3 2− and SO4 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 CO3 2− and SO4 2− 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.