Design and Synthesis of Coumarin–Imidazole Hybrid Chromophores: Solvatochromism, Acidochromism and Nonlinear Optical Properties

Abstract

A set of linear and asymmetric coumarin–imidazole hybrid compounds having a N,N‐diethylamine at 7‐position and imidazole at 3‐position on the coumarin were synthesized. Insertion of thiophene π‐spacer between coumarin and imidazole moieties (5b, 5d) leads to redshifted absorption and emission compared to 5a and 5c. All the compounds show a noticeable response to trifluoroacetic acid with a redshifted absorption and an increase in emission intensity by twofold. The ratio of ground and excited state acidity constant was calculated using Förster energy cycle, and the ratios were found to be 0.25, 0.96, 0.52 and 1.87, respectively, for 5a‐5d. Due to the thiophene π‐spacer, elongation of π‐conjugation in 5b and 5d leads to high values of polarizability (α), first‐order hyperpolarizability (β) and second‐order hyperpolarizability (γ). Compound 5b exhibits a high value (895 GM) of two‐photon absorption cross section (σ2PA), measured using two‐level model.

NLOphoric Triphenylamine Derived Donor‐π‐Acceptor‐π‐Donor Based Colorants: Synthesis, Spectroscopic, Density Functional Theory and Z‐scan Studies

“…B3LYP and BHHLYP a GH functional have a constant percentage of HF exchange, that is 20 and 50%, respectively, whereas CAM‐B3LYP (19–65%), ω B97 (0–100%), ω B97 (15.77–100%) and ω B97 (22.2–100%) an improved range‐separated hybrid functional known for their better performance than that of hybrid functional. These NLO parameters were calculated theoretically and experimentally based on the theory described in our previous reports . The basis set used was the standard triple zeta basis set as 6‐311++G(d,p).…”

Greener and efficient Synthesis of 2,4,5-Trisubstituted Imidazole by using sodium oxalate in aqueous medium

“…Imidazole [5][6][7] is an important heterocyclic system gained remarkable attention due to their diverse application in pharmaceutical [8][9][10][11][12][13] and agrochemical industries [14][15][16] . In addition to this, substituted imidazole derivatives are broadly used in emerging research area like preparation of dyes for solar cells 17 and other optical materials [18][19][20][21][22][23] , as well as synthesis of ionic liquids 24 , functional materials 25 , and organo-catalyst 26 . Due to the high level of interest in substituted imidazoles, a number of methodshave been developed for synthesis of 2,4,5trisubstituted imidazole derivatives by using variouscatalysts such as, Homogeneous Lewis acids [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] , Heterogeneous Lewis acids [43][44][45][46][47][48][49][50][51][52]…”

Recent advances in the synthesis of imidazoles

“…1,2 Despite recent advances, the development of novel methods for the regiocontrolled synthesis of substituted imidazoles is of strategic importance. This is due to the preponderance of applications to which this important heterocycle is being deployed, such as the traditional applications in pharmaceuticals and agrochemicals 3,4 to emerging research into dyes for solar cells and other optical applications, [5][6][7][8][9][10][11][12][13][14][15][16] functional materials, 17 and catalysis 18 (Fig. 1).…”