Vibrational assignment and structure of trinuclear oxo-centered of basic formate iron(III) and chromium(III) complexes: a density functional theory study.

[Fe3O(OOCH)6(H2O)3]OOCH·HCOOH, and [Cr3O(OOCH)6(H2O)3]OOCH·2.5HNO3 were synthesized and the molecular structure and vibrational assignments of their cations were investigated by means of density functional theory (DFT) calculations. The harmonic vibrational frequencies of [Fe3O(OOCH)6(H2O)3]+ and [Cr3O(OOCH)6(H2O)3]+ were obtained at the UB3LYP level using a series of basis sets. The topological properties of the charge distribution of both cations in their ground states are discussed in detail by means of natural bond orbital (NBO) theory and of [Fe3O(OOCH)6(H2O)3]+ by the quantum theory of atoms in molecules (AIM). The calculated geometrical parameters and vibrational frequencies were compared with the experimental results. The scaled theoretical frequencies and the structural parameters were found to be in good agreement with the experimental data.

Synthesis and evaluation of changes induced by solvent and substituent in electronic absorption spectra of some azo disperse dyes.

Five azo disperse dyes were prepared by diazotizing 4'-aminoacetophenone and p-anisidine and coupling with varies N-alkylated aromatic amines. Characterization of the dyes was carried out by using UV-vis, FTIR and 1H NMR spectroscopic techniques. The electronic absorption spectra of dyes are determined at room temperature in fifteen solvents with different polarities. The solvent dependent maximum absorption band shifts, were investigated using dielectric constant (ɛ), refractive index (n) and Kamlet-Taft polarity parameters (hydrogen bond donating ability (α), hydrogen bond accepting ability (ß) and dipolarity/polarizability polarity scale (π*)). Acceptable agreement was found between the maximum absorption band of dyes and solvent polarity parameters especially with π*. The effect of substituents of coupler and/or diazo component on the color of dyes was investigated. The effects of acid and base on the visible absorption maxima of the dyes are also reported.

Fabrication of nanospinel ZnCr2O4 using sol-gel method and its application on removal of azo dye from aqueous solution.

For the first time, nanoparticles of zinc chromite, spinel ZnCr(2)O(4) have been fabricated by the thermal decomposition of Zn-Cr gel prepared by sol-gel method in the presence of oxalic acid as a chelating agent. It was shown that the well-crystallized spinel structure is formed after calcination at 450°C. The nanospinel has been characterized by differential thermal analysis (DTA), X-ray powder diffraction (XRD), infrared spectroscopy (IR), and transmission electron microscope (TEM). The average particle size is approximately 13 nm according to the TEM image. The nanoparticles of zinc chromites showed excellent adsorption properties towards reactive dye, reactive blue 5 (RB5). The adsorption studies have been carried out for contact time, different pH values, different temperatures, and adsorbent doses. The investigation of removal kinetics of RB5 indicates that the removal process obeys the rate of second-order kinetic equation. The results indicate that the Langmuir adsorption isotherm fitted the data better than the Freundlich. Also, the photocatalytic degradation of RB5 using spinel ZnCr(2)O(4) under UV irradiation at pH=1 has been also examined. The results showed that the degradation of RB5 dye follows merely an adsorption process.

Cyclo-hexyl-methyl-ammonium N,N'-dicyclo-hexyl-N,N'-dimethyl-N''-(2,2,2-trifluoro-acet-yl)phospho-nic triamide).

In the salt, C(7)H(16)N(+)·C(16)H(28)F(3)N(3)O(2)P(-), the P atom shows tetra-hedral coordination. Two ion pairs are linked by N-H⋯O hydrogen bonds across a center of inversion. The phosphoryl and carbonyl groups are staggered [O-P-N-C = 64.8 (3)°].

Correlation of gastroesophageal reflux disease with positive family history and headache in Shiraz city, southern Iran.

BACKGROUND/AIMS: To analyze the potential correlation of a positive family history of gastroesophageal reflux disease (GERD) and the history of headaches as a risk factor for and complication of the disease. MATERIALS AND METHODS: Three thousand and six hundred subjects were selected by cluster random sampling from all seven districts of Shiraz city, who were invited for interview. In five months, 1956 subjects participated in this study. A questionnaire organized into three sections of demographic, signs and symptoms of GERD, headache and family history of GERD was completed for each patient. Social and demographic variables were also recorded. RESULTS: The presence of GERD symptoms (72%) had a significant correlation with a positive family history of the disease ( P = 0.000). Patients showed a variable frequency of headache, ranging from once daily (16.7%), three to five times a week (5.6%), once-twice a week (26.7%), once to three times a month (15.0%) and less than once a month (8.3%). There was a significant correlation between the headaches and the GERD symptoms ( P = 0.000). CONCLUSION: A positive family history of GERD can be considered as a risk factor for the disease and the presence of headache at the time of diagnosis as a complication of this disease. Therefore, in the management of GERD, attention should be given to these factors.