The solvent effect on polar compounds containing acidic hydrogens

The effect of aromatic and non-aromatic solvents on the proton chemical shifts of 23 polar compounds has been determined. The protons which are activated by electron-withdrawing groups show large highfield shifts in benzene (relative to the isotropic solvents). Based on evidence provided by infrared data, the highfield shifts of the acidic protons in benzene solution are interpreted in terms of a model involving C? Hπ hydrogen bonding. This model successfully interprets the data reported previously for steroidal ketones. The same model can be extended to benzene solutions of other polar compounds containing strongly electron-deficient sites to which alkyl groups are attached. It is observed that the use of CCl₄ as a reference solvent in studies of benzene induced shifts may have greater significance, since these two solvents have similar dielectric constants.     

STRUCTURE-BORNE NOISE AND VIBRATION OF CONCRETE BOX STRUCTURE AND RAIL VIADUCT

In this study, the vibration and acoustic resonance, and dominant frequency range of simple concrete box and viaduct are examined from the measurement results. A narrow band analysis—fast Fourier transform (FFT) method is used to analyze the measurement results and finite element method (FEM) is used to validate resonance frequencies for noise and vibration. The experiment of the concrete box structure is a preliminary study of analyzing resonance frequency radiated from the vibrating concrete structure since railway viaduct is a concrete box structure too. According to their noise and vibration spectra, it shows that the vibration resonance is more significant than the acoustics resonance.Based on the measurement results of the rail viaduct structure-borne noise and vibration, the relationship in terms of transfer function and coherence between noise and vibration are evaluated. They show that the dominant frequency range for noise and vibration of concrete viaduct is between 20 and 157 Hz, the resonance frequencies are 43 and 54 Hz and have significant tonal noise characteristics. The experimental results are in good agreement with the theoretical relationship between sound and vibration.     

一个用于肿瘤研究中灌流和扩散成像参数分析的应用软件

A software package has been developed to process perfusion, relaxation times and diffusion MRI dat a acquired in cancer research. This software package was written on MATLAB platf orm (Version 6.0). Parameter maps, such as permeability, apparent diffusion coef ficient and T₁ were generated from original MRI data. The features of para metric analysis include ROI analysis, contrast adjust, statistical information generat ion, false color image and zoom in display. Since it was written in Matlab fun ct ions, this package can be used on almost all operation systems (Microsoft window s, Unix, Mac OS & Linux) and it is easy to expand the features.     

Electrochemical Properties of Crown-Containing N-(Thio)phosphoryl(thio)ureas and Their Complexes with 3d Transition Metals

The electrochemical behavior of crown-containing N-(thio)phosphoryl(thio)ureas and their complexes with 3d transition metals was studied by dc voltammetry on a graphite electrode in acetone. Crown-containing N-(thio)phosphoryl(thio)ureas are not reduced but are oxidized on solid electrodes in the examined range of potentials; the electrons are transferred via the (thio)urea group. Electrooxidation of macrocyclic Co(II), Ni(II), and Cu(II) complexes probably occurs via formation of M(III) complex species. Electroreduction of these metal complexes involves stepwise electron transfer, with the oxidation state of the metal atom decreasing to 0, followed by dissociation of the electrochemical reaction products.     

Reaction of o,o-diisopropyl dithiophosphate with nitriles of carboxylic acids

Conclusions The interaction of O,O-diisopropyl dithiophosphate with benzonitrile, phenylacetonitrile, adipodinitrile, and ethyl cyanoacetate proceeds with the formation of unstable imidoyldithiophosphates, which are capable of being rearranged to form the corresponding phosphorylated thioamides. The further course of the reaction is associated with the splitting of the P-N-C or P-S-C bonds in the N-(O,O-diisopropylthiophosphonyl)thioamides and probably of the imidoyldithiophosphates under the action of a second molecule of the dithio acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 861–866, April, 1979.     

On Chiral Space Groups and Chiral Molecules

This note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations).For a chiral molecule,which must crystallize in a chiral space group,the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant.     

Isolation and Spectroscopic Characterization of Protonated Mixed [Tetrakis (4-pyridyl)porphyrinato] (phthalocyaninato)Rare Earth (Ⅲ)Double-decker Compounds

IntroductionThe homoleptic sandwich~type porphyrinato and phthalocyaninato metal complexesRE (P) z and RE2 (P) 3 (RE =rare earth 1 P = Por or Pc) have been intensively studied over sev-eral decades due to their potential application in non-linear optical (NLO) materials, molecu-lar electronic and magnetic ..te.i.l.L1--l6j.The double-deckers have also aroused a growing interest as structural and spectroscopicsynthetic models for the dimmer of bacteriochlorophyl1 molecules in bacterial pho…     

Adsorption recovery and preconcentration of Ni(II), Zn(II), and Cd(II) on nitrocellulose membranes modified with <Emphasis Type="Italic">N</Emphasis>-acylamidophosphates

N-(Thio)phosphorylated (thio)carbamides and (thi o)amides are proposed as modifiers of polymer nitrocellulose membranes for the adsorption preconcentration of Ni(II), Zn(II), and Cd(II) from aqueous solutions. The binding constants of metalions with the immobilized reagents are 1.5–2.5 times higher than those with monomer ligands in solution. The preconcentration coefficients are 1950–3500. Aprocedure was developed for the adsorption preconcentration and recovery of Ni(II), Zn(II), and Cd(II) as complex compounds, using nitrocellulose membranes modified with N-(thio)phosphorylated thiocarbamides and thioamides.     

Structure and Intramolecular Lability of N-(Thio)phosphoryl(thio)amides: XIII. Structure of N-Phenyl-N′-(diisopropoxythiphosphoryl)thiourea

The structure and intramolecular transformations of N-phenyl-N′-(diisopropoxythiophosphoryl)thiourea in (CD₃)₂CO solution were studied by ¹H, ¹³C, and ³¹P NMR spectroscopy. Combined analysis of NMR data and model calculations gave evidence in favor of high conformational and tautomeric flexibility of the thioureas in solution. The Z,E conformation of the amide form with the two N-H bonds cis and trans to the C=S bond was found to be preferred.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 908–911.Original Russian Text Copyright © 2005 by Karataeva, Yul’metov, Zabirov, Aganov, Klochkov.