A Ruthenium Bipyridyl Molecular Dye Sensitizer and an Excited-State Intermolecular Proton Transfer-Active Colorimetric Probe for Anions, with High Affinity Towards CN− in DMSO

Abstract

A ruthenium bipyridyl-dye sensitizer (N) based on the naphthyl-thiazole anchoring-ancillary ligand was synthesized and characterized using spectroscopic methods of UV-Vis, 1 H NMR, FTIR and fluorescence. The functional properties of N were investigated through its photoinduced and intramolecular based charge transfer mechanisms. Subsequently, N displayed interesting charge transfer-based properties (ESIPT) that are complementary to molecular photovoltaic and chemosensing properties. The properties were investigated and studied in dimethyl sulfoxide (DMSO), due to its polar nature and solubility of the dye. Dye sensitizer exhibitions were investigated through solvatochromism effect on the optoelectronic properties, while chemosensing abilities were inspected through colorimetric activities, upon molar addition of anions. Thus, it was established that a dual functional N is a potential dye sensitizer with optoelectronic properties displaying high molar extinction coefficients in acetone. In addition, it was found that N is a colorimetric and fluorometric probe selective and sensitive to biologically important anions of CN − , F − , OH − and AcO − through fluorescence enhancement, as a result of hydrogenbonding leading to deprotonation. The sensing probe, however, displayed more strongly association with CN − .

Tuning ESIPT-coupled luminescence by expanding π-conjugation of a proton acceptor moiety in ESIPT-capable zinc(ii) complexes with 1-hydroxy-1H-imidazole-based ligands

“…In this context, the application of ESIPT-fluorophores for a plethora of sensing purposes has become one of the mainstream interdisciplinary directions fusing together analytical, organic and physical chemistry. [56][57][58][59][60][61][62][63][64][65][66][67][68] Although the molecules of ESIPT-fluorophores can bind metal ions (which is used for the detection of metals), this phenomenon is typically coupled with their deprotonation and the disappearance of ESIPT in the metal complex molecules (Scheme 2, top). [69][70][71][72][73][74][75][76] Nevertheless, the purposeful design of specific sites for metal coordination in the molecules of ESIPT-fluorophores paves the way toward metal ion binding without the deprotonation of ESIPT-fluorophores (Scheme 2, bottom).…”

“…In this context, the application of ESIPT-fluorophores for a plethora of sensing purposes has become one of the mainstream interdisciplinary directions fusing together analytical, organic and physical chemistry. 56–68…”

A facile synthesis of a novel 4-hydroxyl-3-azo coumarin based colorimetric probes for detecting Hg2+ and a fluorescence turn-off response of 3CBD to Fe3+ in aqueous environment

“…In addition, aqueous solution-based sensing probes can be essential in physiological systems, for monitoring the presence and concentration of specic cations of concern, and be able to regulate them. The mode of cation detection is largely based on the design of the molecular framework, normally via several interaction mechanisms, 8,[42][43][44][45] which in many cases characterized by functional groups [46][47][48][49][50] and coordination interaction. [51][52][53][54] Commonly used binding units in colorimetric chemosensors include bipyridines, Schiff bases, guanidine, rhodamine dyes, and azo dyes.…”

First 1-hydroxy-1H-imidazole-based ESIPT emitter with an O–H⋯O intramolecular hydrogen bond: ESIPT-triggered TICT and speciation in solution

“…70–76 The sensitivity of ESIPT-capable molecules to abovementioned stimuli makes them promising sensors for analytical chemistry. 77–101…”