Optical, electrochemical and current−voltage characteristics of novel coumarin based 2,4-dinitrophenylhydrazone derivatives

Coumarin-pyridone conjugate as a fluorescent tag for LFPs visualization and electrochemical sensor for nitrite detection

In this work, a D–π–A based coumarin–pyridone conjugate (CPC) was synthesised by a one-pot multicomponent reaction and the structure was proven from infrared and nuclear magnetic resonance spectroscopies and high-resolution mass spectrometry.

Effect of the substituents of new coumarin-imidazo[1,2-a]heterocyclic-3-acrylate derivatives on nonlinear optical properties: a combined experimental-theoretical approach

A series of new coumarin-imidazo[1,2-a]heterocyclic-3-acrylate derivatives 7a-h were synthesized by the Heck reaction between the corresponding 3-(imidazo[1,2-a]pyrimidines)-(2-yl)-2H-chromen-2-ones 4a-e and methyl acrylate in 45-87% yields. The effect of the distinct substituents on third-order nonlinear optical properties was examined, experimentally measuring their nonlinear refractive indexes by the Z-scan technique. Density functional theory and time-dependent density functional theory were utilized with the B3LYP, CAM-B3LYP, PBE (PBEPBE), and M062X functionals on Gaussian09 software to calculate the vertical excitation, relaxation of the brightest excited states, conformation, HOMO-LUMO gaps, oscillator strength, polarizability, and hyperpolarizabilities of all derivatives. Although all acrylates showed a nonlinear response at a certain level of power, the compounds bearing a diethylamino electron-donating group exhibited higher nonlinear refractive index values (∼10^-9 cm² W^-1), which is in agreement with the trend in the computational calculations of the first and second hyperpolarization. According to the structural analysis, the electron-withdrawing group (acrylate) is mainly responsible for the loss of coplanarity because of increasing the dihedral angle between the coumarin and imidazo[1,2-a]heterocyclic moieties (to 39.1°). On the other hand, the unsubstituted compound 4a presented the greatest nonlinearity due to its almost coplanar structure (n₂ ∼ 10^-8 cm² W^-1), highlighting the importance of this feature.

Synthesis, characterization and biological investigations of potentially bioactive heterocyclic compounds containing 4-hydroxy coumarin

In this paper, we have reported the synthesis of a series of heterocyclic azo dyes containing 4-hydroxy coumarin by diazo-coupling reaction. The structural aspect of the newly synthesized compounds was accomplished by various physico-chemical techniques like UV-Visible, FT-IR, NMR, and mass spectrometry. The computational calculations and geometrical optimization of the newly synthesized azo dyes were investigated by using Gaussian software with the help of Density functional theory (DFT)/B3LYP method using 6-31G(d,p) basis set at gaseous phase. Also, the quantum chemical parameters were evaluated to understand the structural activity concept of the dyes. The pharmacological efficacy of the azo dyes was investigated by antimicrobial, antitubercular, DNA cleavage and in silico molecular docking studies. All the newly synthesized compounds were able to exhibit significant inhibitory activity against tested microbes. Further, the in silico molecular docking showed effective binding properties of the compounds against RpsA target receptor.

Overview on developed synthesis procedures of coumarin heterocycles

Considering highly valuable biological and pharmaceutical properties of coumarins, the synthesis of these heterocycles has been considered for many organic and pharmaceutical chemists. This review includes the recent research in synthesis methods of coumarin systems, investigating their biological properties and describing the literature reports for the period of 2016 to the middle of 2020. In this review, we have classified the contents based on co-groups of coumarin ring. These reported methods are carried out in the classical and non-classical conditions particularly under green condition such as using green solvent, catalyst and other procedures.