Novel Iminocoumarin Derivatives: Synthesis, Spectroscopic and Computational Studies

Abstract

Three novel iminocoumarin derivatives with high quantum yield are synthesized from 3-benzimidazole substituted coumarin and different aromatic aldehydes. The photophysical behavior of the synthesized compounds was studied using UV-visible and fluorescence spectroscopy in polar and non-polar solvents. The compounds show absorption maxima at around 450 nm and emission maxima at around 500 nm. The quantum yields of compounds in dichloromethane and chloroform are more than 0.90. The absorption, emission and quantum yield of compounds are dependent on the polarity of solvents. Along with an intense absorption, these compounds show shoulder absorption peak in the studied solvents. The solvent polarity plots revealed the charge transfer process in the synthesized molecules from donor to acceptor. Density Functional Theory and Time Dependent Density Functional Theory computations have been used to have more understanding of the structural, molecular, electronic and photophysical parameters of the dyes. The dyes were characterized by FT-IR, (1)H NMR, (13)C NMR and mass spectral analysis.

Synthesis and Derivatization of Julolidine: A Powerful Heterocyclic Structure

“…The synthesis of 8‐hydroxyjulolidine ( 5 ) and 8‐methoxyjulolidine ( 6 ) were also reported by Van Gompel and Schuster (1987) and by Chemate and Sekar (2015) (Scheme ). However, differently from the original methodology, in both these studies, the reaction of 3‐methoxyaniline with 1‐bromo‐3‐chloropropane was carried out in the presence of Na 2 CO 3 in attempt to prevent the cleavage of the ether group.…”

“…To the synthesis of 129a , the authors used as solvent CH 2 Cl 2 (r.t., 1–16 h; 60–95 % yield), , , or DMF (0 °C to r.t., 12 h; 67.3 % yield) and (0 °C to 80–100 °C, 2–4.5 h; 42.7–93 % yield) . Julolidine 134 was obtained in 65–97.6 % yield using POCl 3 and DMF at 0–4 °C to r.t. (overnight; 84 % yield), 60 °C (4 h; 80 % yield) or 80–100 °C (0.5 h; 65–97.6 % yield) , , , , . Julolidine 134 was shown to inhibit self‐assembling of β ‐amyloid protein, which constitutes a promising pharmacological approach to treat Alzheimer desease .…”

“…The iminocoumarins 293 and 295 were also obtained by aldol condensation/cyclization with 70 % and 81 % yield, respectively (Scheme and Scheme ) , . Compound 295 was converted to derivative 297 through reaction with aldehyde 296 (71 % yield) (Scheme ) …”

Tuning ‘Stokes Shift’ and ICT Character by Varying the Donor Group in Imidazo[1,5 a]pyridines: A Combined Optical, DFT, TD‐DFT and NLO Approach

“…Synthesis of imidazo[1, 5‐a]pyridine derivatives with different donors is depicted in Scheme . 2‐Benzoylpyridine ( 1 ), salicylaldehyde ( 1 d ), 2‐methoxy benzaldehyde ( 1 e ) and 4‐(diethylamino)‐2‐hydroxy benzaldehyde ( 1 b ) are commercially available whereas 8‐hydroxy‐1,2,3,5,6,7‐hexahydropyrido[3, 2,1‐ij]quinoline‐9‐carb‐aldehyde ( 1 a ) and 2,4‐hydroxy benzaldehyde ( 1 c ) were prepared according to the procedure as described in literature ,. The dyes 2 a‐e were synthesized by condensation of 2‐benzoyl pyridine and substituted aldehydes in presence of ammonium acetate and glacial acetic acid as a reaction solvent at 110° C. The synthesized dyes 2 a‐e were fully characterized by 1 H NMR, 13 C NMR, and mass spectra.…”

Optical properties of 3-substituted indoles

“…7,13,14,[26][27][28][29][30][31][32][33][34][35][36][37] In particular, NLO materials with varied shape and size (e.g. dipolar, quadrupolar, octupolar) were developed and extensively studied using various testing methods such as electric eld induced second harmonic (EFISH) generation, hyper Rayleigh scattering (HRS), [26][27][28][29][30][31][32][33][34][35][36][37] solvatochromic methods [38][39][40][41][42][43][44][45][46] and computational based density functional theory (DFT). 39,42 Among all the methods, the solvatochromic method is most suitable, easy and cost effective method, in which the NLO response, rst hyperpolarizability coefficient (b) of small dipolar molecule can be obtained accurately.…”