Synthesis and Structural Studies of [Na(C7H6O4)(H2O)3](C7H5O4)?·?2H2O

Abstract  The mononuclear complex [Na(C₇H₆O₄)(H₂O)₃](C₇H₅O₄) · 2H₂O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis. The compound crystallizes in the monoclinic space group P2₁ with a = 3.623(2) ?, b = 15.872(6) ?, c = 15.650(5) ?, β = 93.13(4)°, V = 896.6(7) ?³ and Z = 2. The central sodium ion is six coordinated with distorted octahedral geometry by two oxygen atoms from two bridging 3,5-dihydroxybenzoate ligands and four ones from different water molecules. The notable feature of the title complex is the formation of a three-dimensional network, through the combination of coordination bonds, hydrogen bonds and π···π interactions. There are one-dimensional channels in the structure, filled in by water molecules. The compound dehydrates in the temperature range of 70–125 °C and then is stable up to 230 °C. Index Abstract  The mononuclear complex [Na(C₇H₆O₄)(H₂O)₃](C₇H₅O₄) · 2H₂O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis.      

Nonconscious control of fundamental voice frequency

The aim of this paper is to answer the question whether "perception-action" dissociation, which is well documented in vision, may also be found in auditory information processing. Trained singers were asked to produce vowel sounds into a microphone. The sound that each singer produced was fed back to their ears via headphones. Two seconds after the sound production had begun, the auditory feedback was shifted in pitch by a certain degree (9, 19, 50, or 99 cents in either direction). In every set of sounds, instances without any pitch shifts also appeared. After each trial, participants reported whether they were aware of a pitch change or not. It was found that even though the participants were unaware of subtle pitch changes, the fundamental frequency of their vowel production was found to shift slightly in the opposite direction to the pitch shift. These results show that auditory information is processed by two separate systems: one for perception and one for action. They also show that the function of the auditory control system differs from the visual control system. The latter is used to control bodily movements while the function of the former is a nonconscious, instant control of vocalization.     

STUDIES ON PYRAZINE DERIVATIVES. XL. SYNTHESIS,REACTIVITY, AND TUBERCULOSTATIC ACTIVITY OF 4-HYDROXYALKYL-5-PYRAZINYL4H-[1,2,4]-TRIAZOLE-3-THIONES

2,2′-Sulfinyl-bis(4-methyl phenol) 3 and it's thio derivative have been synthesized in this work. The reduction process of sulfoxide 3 to its thio derivative 5 was accomplished in the presence of Zn/AcOH/SiO₂, under microwave irradiation. The structures have been confirmed by spectroscopic (IR, ¹HNMR, ¹³CNMR) and single crystal x-ray diffraction methods. 2,2′-Sulfinyl-bis(4-methyl phenol) 3 crystallizes in the space group Cc of the monoclinic system with four molecules in the unit cell of dimensions a = 11.425(2) Å, b = 13.530(2) Å, c = 9.5215(17) Å, β = 117.289(4) Å, and 2,2′-thio-bis(4-methyl phenol) 5 crystallizes in the space group P 2₁2₁2₁ of the orthorhombic system with four molecules in the unit cell of dimensions a = 9.021(1) Å, b = 10.523(2) Å, c = 13.607(2) Å, α = 90. The structures have been refined to final values for the crystallographic R factor of 0.0189(3) and 0.0248(5) based on 2999 and 3720 observed independent reflections respectively.     

Synthesis, mesomorphic and optical properties of isothiocyanatotolanes

The synthesis, mesomorphic properties and UV absorption spectra of laterally fluorine substituted, and the corresponding unsubstituted, 4'-alkyl-, 4'-alkoxy-, 4'-alkylcyclohexyl-, 4'-alkylbicyclo [2,2,2]octyl- and 4'-alkylcyclohexylethyl-4-isothiocyanatotolanes are described. Multicomponent broad range nematic mixtures with birefringence values higher than 0.4 and moderate viscosities are developed.     

A new method of preparation of the anionic decacarbonyls M2(CO)102− (M = Cr,Mo, W) and syntheses and properties of Mg(THF)2[M2(CO)10]

The anionic decacarbonyIs M₂(CO)₁₀^2? were synthesized via reduction reactions of CrCl₃, MoCl₅ and WCl₆ with metallic magnesium or sodium amalgam under carbon monoxide. Chemical properties and IR characteristics of the magnesium salt Mg(THF)₂[M₂(CO)₁₀] are desribed.     

Separation of synthetic food colourants in the mixed micellar system. Application to pharmaceutical analysis

The paper presents a rapid method for the determination of commonly used synthetic food dyes by micellar electrokinetic capillary chromatography. Detection and separation conditions allowing complete resolution of 15 synthetic food colourants were investigated. The effect of different surfactants on the analytes mobility in relation to their structure was tested. After optimization procedure a dual micellar system was selected. All food dyes were separated in less then 20 min using a fused silica capillary in the borate/dodecylsulfate/deoxycholate buffer containing acetonitrile as organic modifier. The detection wavelength was set at 210nm. The method was successfully validated by determination of linearity ranges, detection limits, precision and repeatability for all colourants tested. In order to apply the method for pharmaceutical analysis a sample pretreatment procedures were found. Liquid pharmaceuticals were used as it or just after dilution with water. From tablets or capsules the colourants were isolated by adsorption on acidic aluminium oxide. The method was used for identification and if possible for quantification the synthetic food dyes in pharmaceuticals. The analytes are detectable at a concentration level 0.3-0.8 microg ml(-1).     

Capillary Condensation in Pores with Energetically Heterogeneous Walls: Density Functional versus Monte Carlo Calculations

We investigate adsorption of a Lennard-Jones fluid in slit-like pores with energetically heterogeneous walls by using Grand Canonical Monte Carlo simulations and a density functional approach. The model of a fluid-wall potential is qualitatively similar to that invoked by R?cken et al. (J. Chem. Phys. 108, 8089, (1999); i.e., it consists of a homogeneous part that varies in the direction perpendicular to the wall and a periodic part, varying also in one direction parallel to the wall, but in contrast to the above mentioned work, both parts of the fluid-wall potential are modeled by Lennard-Jones (9, 3) type functions. The structure of the adsorbed film is characterized by local densities. We evaluate the phase diagrams for several systems characterized by different corrugation of the adsorbing potential and discuss the discrepancies between theoretical predictions and computer simulations. Copyright 2001 Academic Press.     

Adsorption of acetone on the mercury electrode from H2O+(CH3)2CO+HCl solutions

The adsorption of acetone on a mercury electrode from (CH₃)₂CO+H₂O+HCl solutions has been studied using a thermodynamically rigorous procedure. The chemical potential of the supporting electrolyte has been kept constant by using the concentrations corresponding to the constant e.m.f. of the cell with electrodes reversible to each of the ions in the solutions. It is suggested that the molecule is to some extent oriented with the hydrocarbon part towards mercury. The composition of the surface layer has been calculated.