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A glycerol‐triazole tethered rhodamine based colorimetric and fluorimetric sensor 3′,6′‐bis(diethylamino)‐2‐(((1‐(1,3‐dihydroxypropan‐2‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methylene)aminospiro [isoindoline‐1,9′‐xanthen]‐3‐one (L1) is designed and synthesized for the selective recognition of Cu2+ ion. The sensor L1 allows naked eye detection of Cu2+ ion with a fast response (<1 min). Among the various metal ions tested, the sensor L1 shows selective binding with Cu2+ through turn‐on fluorescence mechanism. The sensor shows 1 : 2 binding stoichiometry with binding constant, Ka=1.1×106 M−2 as revealed by job's plot & Benesi‐Hildebrand plot (B−H plot), respectively. The detection limit of L1 with Cu2+ ion is found to be 3.3 μM. Further, the experimental results are also validated using density functional theoretical (DFT) study. The optimized geometries indicates that the formation of the L1‐Cu2+ complex is thermodynamically favourable by ΔG=−11.7 kcal/mol. The HOMO‐LUMO gap of the ligand L1 is found to be 3.49 eV, which decreases to 1.76 eV upon complexation with copper. [ABSTRACT FROM AUTHOR]

An oxidovanadium(V) complex [VO(SGly)(bpy)]ClO4 (H2SGly=N‐(2‐hydroxybenzyl)‐L‐glycine; bpy=2,2′‐bipyridine) was synthesized and characterized by spectroscopic studies (IR, UV‐vis, ESI‐MS). The theoretical structure of the complex was optimized by density functional theory (DFT) calculations. The multifunctionality of this oxidovanadium complex was demonstrated by the application of it as a catalyst in peroxidative bromination of single‐pot conversion of phenol red to bromophenol blue, whereas its nuclease activity was established by DNA cleavage. The interaction of this oxidovanadium complex with DNA was studied by various physicochemical tools like UV‐vis, fluorescence, and viscosity measurement studies. The intrinsic binding constant of the complex with DNA was determined spectrophotometrically and calculated to be (2.3 ± 0.02) x 104 M−1. The spectroscopic studies and the viscosity measurements indicate that the complex binds to the groove of CT‐DNA, but whether to the major or minor groove that was not established. The extent of vanadium complex induced DNA cleavage was studied by gel electrophoresis techniques. The complex was found to promote cleavage of pUC19 plasmid DNA from the super coiled (SC DNA) form I to nicked coiled (NC DNA) relaxed form II. [ABSTRACT FROM AUTHOR]

A glycerol‐triazole tethered rhodamine based colorimetric and fluorimetric sensor 3′,6′‐bis(diethylamino)‐2‐(((1‐(1,3‐dihydroxypropan‐2‐yl)‐1H‐1,2,3‐triazol‐4‐yl)methylene)aminospiro [isoindoline‐1,9′‐xanthen]‐3‐one (L1) is designed and synthesized for the selective recognition of Cu2+ ion. The sensor L1 allows naked eye detection of Cu2+ ion with a fast response (<1 min). Among the various metal ions tested, the sensor L1 shows selective binding with Cu2+ through turn‐on fluorescence mechanism. The sensor shows 1 : 2 binding stoichiometry with binding constant, Ka=1.1×106 M−2 as revealed by job's plot & Benesi‐Hildebrand plot (B−H plot), respectively. The detection limit of L1 with Cu2+ ion is found to be 3.3 μM. Further, the experimental results are also validated using density functional theoretical (DFT) study. The optimized geometries indicates that the formation of the L1‐Cu2+ complex is thermodynamically favourable by ΔG=−11.7 kcal/mol. The HOMO‐LUMO gap of the ligand L1 is found to be 3.49 eV, which decreases to 1.76 eV upon complexation with copper. [ABSTRACT FROM AUTHOR]