This paper presents a simple, low cost method of synthesizing TiO2 nanoparticles by sol-gel method, where titanium isopropoxide is used as a starting material. Further, same TiO2 is used to sensitize 2-cyano-3-(4-(7-(5-(4-(diphenylamino) phenyl)-4-octylthiophen-2-yl) benzo[c] [1, 2, 5] thiadiazol-4yl)phenyl) acrylic acid (RK-1 dye) and Di-tetrabutylammonium cis-bis (isothiocyanato) bis (2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II) (N-719 dye) for light harvesting applications. Anatase structure and average particle size of 7.3 nm were confirmed from XRD pattern. From SEM, it was noticed that particles were of varying size and shape and aggregation with clear porosity. FTIR spectra reveal Ti-O bond corresponding to 483 cm-1 and from UV-Vis absorption, energy band gap was found to be 3.2 eV. Photocurrent density (J)-photovoltage (V) characteristic of DSSC of different thicknesses of TiO2 were obtained, it was observed that optimum solar energy to electricity conversion efficiency () for RK-1 dye and N-719 dye 4.08 % and 5.12 % with TiO2 thickness of 5.4 μm and 8.6 μm respectively under AM 1.5 irradiation (1000 W/m 2) conditions.
A series of novel 2,3‐dihydroquinazolin‐4(1H)‐ones 7 a‐g were designed, synthesized and were characterized by IR, 1H & 13C NMR, MS, and elemental analysis. The optical and electrochemical properties have been studied using UV‐Vis absorption, fluorescence spectroscopy, life time and cyclic voltammetry (CV) measurements. Quantum yield and effect of solvents for the compounds 7 a‐g were investigated. Density Functional Theory (DFT) computations have been carried out for all the synthesized compounds and the computed values found to be approximately in close agreement with the experimental results. Further, the compounds 7 a, 7 d, 7 f and 7 g were evaluated for their anticancer activity at National Cancer Institute, NIH, Bethesda, USA and have shown moderate to good anticancer activities.
Fluorescence investigations on interactions between 7,8-benzo-4-azidomethyl coumarin (7BAMC) and quenchers ortho-phenylenediamine (OPD) and para-phenylenediamines (PPD) in binary solvent mixtures (THF + water) have been reported. UV-absorption study indicated a weak hydrophobic interaction between 7BAMC and the para isomer. NMR spectral studies indicated the presence of an interaction between 7BAMC and PPD. Magnitudes of the parameters associated with FRET, showed the presence of interactions between 7BAMC and PPD quencher is more predominant than OPD. Fluorescence quenching studies reveal the role of static and dynamic quenching pathways, depending upon Stern-Volmer constant, dielectric constant and dominant non-radiative processes. Binding equilibria analysis indicates a strong interaction between 7BAMC and PPD than OPD and formation of H-bonding. Based on the magnitudes of free energy, enthalpy change and entropy, bimolecular interaction process may be considered as spontaneous and hydrophobic.
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