Crystal structure of 7,8-benzocoumarin-4-acetic acid.

The fused-ring system in the title compound [systematic name: 2-(2-oxo-2H-benzo[h]chromen-4-yl)acetic acid], C15H10O4, is almost planar (r.m.s. deviation = 0.031 Å) and the Car-C-C=O (ar = aromatic) torsion angle for the side chain is -134.4 (3)°. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, generating [100] C(8) chains, where the acceptor atom is the exocyclic O atom of the fused-ring system. The packing is consolidated by a very weak C-H⋯O hydrogen bond to the same acceptor atom. Together, these inter-actions lead to undulating (001) layers in the crystal.

Crystal structure of 2-(5-meth-oxy-1-benzo-furan-3-yl)acetic acid.

The benzo-furan residue in the title compound, C11H10O4, is essentially planar (the r.m.s. deviation for the nine non-H atoms = 0.011 Å). While the meth-oxy group is coplanar with the fused ring system [C-C-O-C torsion angle = 3.1 (3)°], the acetic acid residue occupies a position almost prime [C-C-C-C = 77.0 (2)°]. In the crystal, centrosymmetrically related mol-ecules are linked by O-H⋯O hydrogen bonds to form eight-membered {⋯HOCO}2 synthons. The dimeric aggregates assemble into supra-molecular layers in the ab plane via benzene-C-H⋯O(ring) inter-actions.

Influence of Sn doping on structural, optical and electrical properties of ZnO thin films prepared by cost effective sol-gel process.

Tin (Sn) doped zinc oxide (ZnO) thin films were synthesized by sol-gel spin coating method using zinc acetate di-hydrate and tin chloride di-hydrate as the precursor materials. The films were deposited on glass and silicon substrates and annealed at different temperatures in air ambient. The agglomeration of grains was observed by the addition of Sn in ZnO film with an average grain size of 60 nm. The optical properties of the films were studied using UV-VIS-NIR spectrophotometer. The optical band gap energies were estimated at different concentrations of Sn. The MOS capacitors were fabricated using Sn doped ZnO films. The capacitance-voltage (C-V), dissipation vs. voltage (D-V) and current-voltage (I-V) characteristics were studied and the electrical resistivity and dielectric constant were estimated. The porosity and surface area of the films were increased with the doping of Sn which makes these films suitable for opto-electronic applications.

4-(4-Chloro-phen-yl)-N-[(E)-4-(dimethyl-amino)-benzyl-idene]-1,3-thia-zol-2-amine.

The title compound, C(18)H(16)ClN(3)S, adopts an extended mol-ecular structure. The thia-zole ring is inclined by 9.2 (1) and 15.3 (1)° with respect to the chloro-phenyl and 4-(dimethyl-amino)-phenyl rings, respectively, while the benzene ring planes make an angle of 19.0 (1)°. A weak inter-molecular C-H⋯π contact is observed in the crystal structure.

Optical, electrical and dielectric properties of TiO2-SiO2 films prepared by a cost effective sol-gel process.

Titanium dioxide (TiO(2)) and silicon dioxide (SiO(2)) thin films and their mixed films were synthesized by the sol-gel spin coating method using titanium tetra isopropoxide (TTIP) and tetra ethyl ortho silicate (TEOS) as the precursor materials for TiO(2) and SiO(2) respectively. The pure and composite films of TiO(2) and SiO(2) were deposited on glass and silicon substrates. The optical properties were studied for different compositions of TiO(2) and SiO(2) sols and the refractive index and optical band gap energies were estimated. MOS capacitors were fabricated using TiO(2) films on p-silicon (100) substrates. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics were studied and the electrical resistivity and dielectric constant were estimated for the films annealed at 200°C for their possible use in optoelectronic applications.

6-Chloro-4-(4-methyl-phen-oxy-meth-yl)-2H-chromen-2-one.

In the title compound, C(17)H(13)ClO(3), the coumarin and phen-oxy moieties are essentially co-planar, making a dihedral angle of 1.99 (7)°. The phen-oxy moiety is oriented anti-periplanar with respect to the coumarin ring as indicated by the C-C-O-C angle of -179.97 (16)°. In the crystal, the sheet-like packing is stabilized by inter-molecular C-H⋯O and C-H⋯Cl hydrogen bonds.

Spectroscopic and electrical properties of SiO2 films prepared by simple and cost effective sol-gel process.

Amorphous SiO2 thin films were prepared on glass and silicon substrates by cost effective sol-gel method. Tetra ethyl ortho silicate (TEOS) was used as the precursor material, ethanol as solvent and concentrated HCl as a catalyst. The films were characterized at different annealing temperatures. The optical transmittance was slightly increased with increase of annealing temperature. The refractive index was found to be 1.484 at 550 nm. The formation of SiO2 film was analyzed from FT-IR spectra. The MOS capacitors were designed using silicon (100) substrates. The current-voltage (I-V), capacitance-voltage (C-V) and dissipation-voltage (D-V) measurements were taken for all the annealed films deposited on Si (100). The variation of current density, resistivity and dielectric constant of SiO2 films with different annealing temperatures was investigated and discussed for its usage in applications like MOS capacitor. The results revealed the decrease of dielectric constant and increase of resistivity of SiO2 films with increasing annealing temperature.

Effect of sintering on optical, structural and photoluminescence properties of ZnO thin films prepared by sol-gel process.

Zinc oxide (ZnO) thin films have been deposited on glass substrates via sol-gel technique using zinc acetate dihydrate as precursor by spin coating of the sol at 2000 rpm. Effects of annealing temperature on optical, structural and photo luminescence properties of the deposited ZnO films have been investigated. The phase transition from amorphous to polycrystalline hexagonal wurtzite structure was observed at an annealing temperature of 400 degrees C. An average transmittance of 87% in the visible region has been obtained at room temperature. The optical transmittance has slightly increased with increase of annealing temperature. The band gap energy was estimated by Tauc's method and found to be 3.22 eV at room temperature. The optical band gap energy has decreased with increasing annealing temperature. The photoluminescence (PL) intensity increased with annealing temperature up to 200 degrees C and decreased at 300 degrees C.

Influence of surfactant and annealing temperature on optical properties of sol-gel derived nano-crystalline TiO2 thin films.

Titanium dioxide thin films have been synthesized by sol-gel spin coating technique on glass and silicon substrates with and without surfactant polyethylene glycol (PEG). XRD and SEM results confirm the presence of nano-crystalline (anatase) phase at an annealing temperature of 300 degrees C. The influence of surfactant and annealing temperature on optical properties of TiO(2) thin films has been studied. Optical constants and film thickness were estimated by Swanepoel's (envelope) method and by ellipsometric measurements in the visible spectral range. The optical transmittance and reflectance were found to decrease with an increase in PEG percentage. Refractive index of the films decreased and film thickness increased with the increase in percentage of surfactant. The refractive index of the un-doped TiO(2) films was estimated at different annealing temperatures and it has increased with the increasing annealing temperature. The optical band gap of pure TiO(2) films was estimated by Tauc's method at different annealing temperature.

4-Bromo-methyl-6-meth-oxy-2H-chromen-2-one.

The structure of the title coumarin derivative, C(11)H(9)BrO(3), is stabilized by weak inter-molecular C-H⋯O hydrogen bonds.

4-Bromo-methyl-7,8-dimethyl-coumarin.

In the title mol-ecule, C(12)H(11)BrO(2), all non-H atoms with the exception of the Br atom are essentially coplanar (r.m.s. deviation = 0.018 Å). The C-Br bond is inclined by 80.17 (12)° to this plane. The crystal structure is stabilized by weak C-H⋯O hydrogen bonds.

Optical, dielectric and morphological studies of sol-gel derived nanocrystalline TiO2 films.

Nanocrystalline TiO(2) films have been synthesized on glass and silicon substrates by sol-gel technique. The films have been characterized with optical reflectance/transmittance in the wavelength range 300-1000 nm and the optical constants (n, k) were estimated by using envelope technique as well as spectroscopic ellipsometry. Morphological studies have been carried out using atomic force microscope (AFM). Metal-Oxide-Silicon (MOS) capacitor was fabricated using conducting coating on TiO(2) film deposited on silicon. The C-V measurements show that the film annealed at 300 degrees C has a dielectric constant of 19.80. The high percentage of transmittance, low surface roughness and high dielectric constant suggests that it can be used as an efficient anti-reflection coating on silicon and other optical coating applications and also as a MOS capacitor.

4-Bromo-methyl-7-methyl-6,8-dinitro-coumarin.

The crystal structure of the title compound, C(11)H(7)BrN(2)O(6), establishes the substitution positions of the nitro groups from the nitration reaction of 7-methyl-4-bromo-methyl coumarin. The mean planes of the nitro groups form dihedral angles of 43.9 (8) and 52.7 (10)° with the essentially planar [maximum deviation 0.031 (6) Å] benzopyran ring system.

Evaluation of bioequivalence of two formulations containing 100 milligrams of aceclofenac.

The bioequivalence of two oral formulations containing aceclofenac 100 mg was determined in 24 healthy Indian male volunteers. The study was designed as a single dose, fasting, two-period two-sequence crossover study with a washout period of 1 week. The content of aceclofenac in plasma was determined by a validated HPLC method with UV detection. The preparations were compared using the parameters area under the plasma concentration-time curve (AUC0-t), area under the plasma concentration-time curve from zero to infinity (AUC0-infinity), peak plasma concentration (Cmax), and time to reach peak plasma concentration (tmax). No statistically significant difference was observed between the logarithmic transformed AUC0-infinity and Cmax values of the two preparations. The 90% confidence interval for the ratio of the logarithmic transformed AUC0-t, AUC0-infinity, and Cmax were within the bioequivalence limit of 0.80-1.25.