Molecular geometries, electronic structures, and optical absorption spectra were investigated using density functional theory (DFT) at the HF/3-21G and B3LYP/3-21G levels for heteroleptic ruthenium dye, both in the gas phase and in water solution. The vertical excitation energies were calculated within the framework of the time-dependent DFT (TD-DFT) approach, whereas the solvent effects were taken into account using the conductor like polarizable continuum model (CPCM). Our results show that the three highest occupied molecular orbitals (HOMOs) are composed of Ru 4d orbitals. The spectra in the range of 350-600 nm were found to originate from metal-to-ligand charge-transfer (MLCT) transitions. The solvent effects lead to changes in both the geometries and the absorption spectra. The results of this work suggest that Ruthenium-based complexes might be effective sensitizers for next-generation dye-Sensitized Photoelectrochemical Cell.

We studied the description of charge-transfer excitations in [CuL₂]⁺ (L=6,6′-dimethyl-2,2′-bipyridine-4,4′-bis(propenoic acid)) dye sensitizer. This dye was studied using density functional theory (DFT), and the electronic absorption spectrum was investigated via time-dependent DFT (TD-DFT) with several hybrid functional, both in the gas phase and in acetonitrile solution. We also have investigated HOMO and LUMO levels in gas and solvent phases for these dyes. The HOMOLUMO transition describes all lowest singlet excited states. We performed TDDFT calculations at the B3LYP/6-31G(d) level of theory. Solvation effects were included by the conductor-like polarizable continuum model (CPCM ). The excitation in the range 500-800 nm of absorption spectra confirms metal-to-ligand charge-transfer (MLCT) transitions. The results of this work suggest that the copper complexes are effective as sensitizers for DSSCs and they can replace ruthenium (II) complexes.

The polymer-bound phosphonium salts are known as disinfectants, being important for drugs with prolonged activity and less toxicity, antifouling coatings and fiber finishing, water and air disinfection. The toxicity (expressed as the logarithm of oral lethal dose for mouse) was related to the structural features of a series of organic phosphonium salts by MLR. The structure of these compounds was modeled by molecular mechanics calculations and descriptors were then derived from the minimized structures. The structural features thus derived important for compound toxicity were derived by MLR combined with genetic algorithm for variable selection. Phosphonium salts toxicity was influenced by their electron distribution and steric factors.

A series of benzothiazolylthioacetyl amino acid and peptide derivatives including glycoside, hydrazide and hydrazone moieties were synthesized with the aim of evaluating their antifungal activity. Their chemical structures were confirmed by 1 H NMR, IR, mass spectrometry and elemental analyses. Out of the thirty two tested compounds three derivatives have enhanced activity as fluconazole at 100 ppm and six at 1000 ppm toward Candida albicans whereas, they were actually inactive toward Aspergillus flavus.

part of the present armory of the clinicians. The synthesis and antibacterial activity of several new ethyl 2-amino-4-methylthiazole-5-carboxylate(1)⁵derivatives substituted at 2^nd position by aryl aldehydes of the thiazole moiety have shown some to increase the antibacterial activity of thiazole. In this study we thought to synthesize thiazole system incorporating substituted aryl aldehydes. The most active compound was 4-methyl-5-hydrazine hydrate-2-(4-methoxy-3-hydroxy benzene) methyleneamino thiazole-5-carboxylate (3c) equipotent to Ciprofloxacin.C₂ position of thiazole ring requires large hydrophilic, electronegative functional moieties like substituted phenyl ring etc for enhanced antibacterial activity of thiazole. In our compounds alkyl (methyl) group is present, still most of the compounds show good antibacterial activity.C₅ position of thiazole ring requires small hydrophobic, electronegative functional moieties like amino, hydrazine hydrate attach with ester for antibacterial activity of thiazole in general.

The structural data and vibrational frequencies of 1- and 2-silaallenes have been studied computationally using the Gaussian 03 suite of programs. All of 15 normal modes were assigned to one of six types of motion (symmetrical stretching, antisymmetrical stretching, scissoring, rocking, wagging, twisting) determined by a group of quantum chemical analysis. Predicted geometric features, vibrational frequencies, and infrared intensities are also reported herein.

In this study, MCM-41-SO₃H has been regarded as an efficient catalyst for the synthesis of aldimines and ketimines by the reaction of carbonyl compounds with primary amines at room temperature in excellent conversion yields.

A systematic investigation of the Ge(CH₃)₂, CH₃GeSiH₃, CH₃GeGeH₃, XGeCY₃ (X; Y = H, F, Cl, Br) species was carried out using the DFT functionals BLYP, B3LYP and BHHLYP. Predicted are the singlet-triplet energy gaps and four types of neutral-anion separations: adiabatic electron affinity (EA_ad), zero-point vibrational energy corrected EA_ad(ZPVE), vertical electron affinity (EA_vert), and vertical detachment energy (VDE). The basis sets used for all atoms are of double-ζ plus polarization quality with additional s- and p-type diffuse functions denoted DZP++. The geometries are fully optimized with each functional independently. Vibrational frequency analyses are performed to compute zero-point energy corrections and to determine the nature of the stationary points. The EA_ad(ZPVE) values (eV) obtained with the BHLYP functional is Ge(CH₃)₂ = 0.46 eV, CH₃GeSiH₃ = 1.22 eV and CH₃GeGeH₃ = 1.26 eV, and FGeCCl₃ = 1.66 eV. The singlet-triplet splittings range from 1.28 eV (HGeCF₃) to 2.22 eV (FGeCCl₃). The XGeCY₃ (Y = Br) species are most often characterized by three-membered cyclic systems involving the divalent germanium atom, the carbon atom and a halogen atom. The predicted results are helpful for the synthesis, characterizations, and applications of these germylene derivatives.

Dyes ions have a tendency to self-associate in aqueous solutions. Since almost all textile dyes are applied from aqueous systems, it is important to understand the association of dyes in water, and to determine the number of chemical species presented in the system. The aggregation of the dyes in aqueous solution is influenced by: the dye concentration, electrolyte concentration, and temperature. In the present work, the qualitative and quantitative analysis of the aggregation of two disazo direct dyes (DSA, and DAS) is presented. The molecular aggregation of studied dye has been studied spectrophotometrically in aqueous solutions as a function of dye concentration (10^-6 ÷10^-3 M). In case of DSA dye, in concentration range 1^.10^-6 ÷ 1^.10^-5 M and 5^.10^-5 ÷ 1^.10^-3 M, as the concentration increases, the extinction coefficient at 416.5 nm decreased. Between concentrations 1^.10^-5 ÷ 5^.10^-5 M an increase of extinction coefficient was observed, and the shape of the spectra changed; all this shifts indicate that the molecules are beginning to aggregate. In case of DAS dye, a change in the absorption spectra shape was observed at concentrations bigger than 5^.10^-5 M. From the mathematical obtained data the number of species presented in the system, in domain of concentrations investigated, was determined. The mathematical calculations confirm the experimental data regarding the aggregation of the DSA, and DAN dyes. From the matriceal analysis, the number of chemical species presented in the system (in domain of concentrations studied) was determined to be three in case of DSA dye, respectively four in case of DAN dye.

The aim of this work was to investigate the efficiency of copolymer microbeads (styrene-divinylbenzene functionalized with trimethylamonium groups) as adsorbents for removal of direct dyes (orange OD, and green GD) from aqueous solutions. The influence of initial concentration, and contact time on the adsorption have been investigated. With increasing of the initial dye concentration, the amount of dye adsorbed increased, while the percentage removal decreased, indicated that the dye removal is concentration dependent. The adsorption kinetics of the removal of studied dyes has been investigated. The kinetics of adsorption is described by the first-order Lagergren model, and pseudo second-order. The correlation coefficients (R²) were used to determine the best fitting kinetic model. The best fits were obtained with the second order kinetic model (higher values of R²), meaning that the adsorption process for OD and GD dyes removal, can be described by the pseudo-second order kinetic model.