摘要:

According to the high sensitivity of TICT (twisted intramolecular charge transfer) emission to external electric field strength, a novel fluorescence sensing mode for ions and neutral molecules in aqueous solution was proposed by using ionic micelle mediated TICT dual fluorescence was proposed. In the sensing system the ionic micelle acts as electric field mediator for the TICT fluorophore. Examples were given for sensing potassium nitrate, sodium dodecylsulfate, and β-cyclodextrin by using sodium p-diethylaminobenzoate(SDEAB)/cetyltrimethylammoinum bromide(CTAB) micelle sensing system. Linear response of dual fluorescence intensity ratio Ia/Ib to analyte concentration with correlation coefficient higher than 0.99 was observed for three analytes.

ISSN:0038-7010    

DOI:10.1080/00387019708006739

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The low spectral region of procaine was studied by far-infrared spectroscopy. Raman lines were registered and interpreted. An equivalent study was performed on the molecule of benzocaine. In the characterization of the bands, and in the description of the torsion-inversion mode of thep-amino group, the AM1 semiempirical method was used. The optimum geometry parameters, the torsion and inversion potential functions, the energy levels, and the transitions were obtained. The effects of temperature on the torsion and inversion modes were studied.

ISSN:0038-7010    

DOI:10.1080/00387019708006740

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The 2,2,6,6-tetramethyl-I-piperidinyloxy free radical (TEMPO) was used as a probe to study the changes in hydrogen bonding between the phenolic OH group and the ON group of the radical by means of NMR and EPR.13C NMR contact shifts induced by TEMPO were measured for five phenols. Formation of intermolecular hydrogen bond between a phenol and TEMPO molecule causes noticeable increase of14N hyperfme coupling constant in the radical and appearance of negative spin density on carbon nuclei of C-OH fragment in the phenol.

ISSN:0038-7010    

DOI:10.1080/00387019708006741

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

5-allyl-2-hydroxy-3-methoxyazobenzene was preperad by the reaction of 4-allyl-2-methoxyfenol and benzenediazoniumchloride and crystallized from dimethylsulphoxide to yield crystals suitable for analysis. The molecular structure was identified by UV-VIS, IR,1H-NMR,13C-NMR and elemental analysis. The crystal structure of the title compound was determined as monoclinic by by single crystal X-Ray diffraction technique. The crystal parameters of this compound are as follows: monoclinic P 2 1/n, a=5.559(2) Å,b=14.900(2) Å, c= 17.573(29 Å, P = 98.58(1)†, V = 1439.3(2) Å3, Z = 2, Dx = 0.610 g/cm3, F(OOO) = 284, λ (MoKα) = 0.71070 Å, μ = 0.041 mm−1. The structure was solved by SHELXS-86 and refined by SHELXL-93. R = 0.09 for 1107 observed reflections with I > 2σ (I).

ISSN:0038-7010    

DOI:10.1080/00387019708006742

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Effect of p-cyclodextrin (β-CD) on micellization of cetyltrimethylammonium bromide (CTAB) in aqueous solution was investigated by twisted intramolecular charge transfer (TICT) dual fluorescence of sodium p-dimethylaminobenzoate (SDMAB). It was shown that β-CD induces the micellization of CTAB and the aggregation of CTAB below CMC as well. A reduced charge density at CTAB micelle interface in the presence of β-CD, due to the incorporation of 1:1 CTAB-β-CD inclusion complex in micelle, was concluded to be the reason for β-CD induced micellization of CTAB.

ISSN:0038-7010    

DOI:10.1080/00387019708006743

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The infrared and Raman spectra of tetracalcium phosphate (Ca4P2O9) were measured and interpreted on the basis of factor group analysis. Factor group splitting can be noted for the various internal vibrational modes of the PO43-ion. However, a fewer number of factor group-split bands can be seen than predicted because of either the weak intensities of these bands or the convolution of such bands for the various internal modes of vibration.

ISSN:0038-7010    

DOI:10.1080/00387019708006744

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Three simple and rapid methods for the determination of guanoxan sulphate in tablets, urine and serum are presented. The first method is based on the direct measurement of the first (1D) and second (2D) (peak-trough) derivative values at 274–250 nm and 276–260 urn respectively. The other two methods depend on the formation of a charge- transfer chromogen with either tetracyanoethylene (TCNE) and 7,7,8,8- tetracyanoquinodimethane (TCNQ). The absorbance of the color developed at 416 and 840 nm respectively. The first and second derivative (1D &2D) values for the charge- transfer products were also measured. The methods were proved to be accurate and reproducible as indicated by relative standard deviation of less than 2%. The proposed methods have been applied to the determination of guanoxan sulphate in tablets, and spiked human urine and serum.

ISSN:0038-7010    

DOI:10.1080/00387019708006745

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

When obtained in sulphuric acid medium sulphato-2-aminopyridine-palladium (II) complex has a polynuclear structure, with a bridging coordination of both the sulphato-group and 2-aminopyridine. The complex keeps its polynuclear structure in alkaline solution, in which the substitution of sulphato ions by hydroxylic groups yields hydroxo-2-aminopyridine-palladium (II). The compounds discussed are the main components of activators used in currentless metallization of nonconducting surfaces.

ISSN:0038-7010    

DOI:10.1080/00387019708006746

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The electronic absorption spectra oftrans-[Cu(sap)2], where (Hsap = salicylidene-o-aminopyridine (Schiff base)), were measured in various solvents at room temperature. The d-d transition energies is used to derive the angular overlap model (AOM) parameters in C2hsymmetry. The experimental curves were resolved by Gaussian analysis. A comparison of the spectra, ligand field parameters and stereochemistries in various solutions was made. The effect of the solvents upon the σ, π-bonding, and bite angle of the bidentate ligand is discussed.

ISSN:0038-7010    

DOI:10.1080/00387019708006747

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

A fast procedure has been developed for the direct determination of paint solvents. The method is based on the injection of small volumes of untreated solvent mixtures into a heated Pyrex glass reactor in which the sample is volatilized and introduced by means of a flow of nitrogen into an IR multiple pass gas cell and the spectrum in the mid-IR region is registered as a function of time. Data found for samples are interpolated in calibration graphs obtained by injecting different volumes of pure compounds which constitute the solvent mixture. A methylisobutylketone (MIBK) toluene mixture was used as test system to develop the proposed procedure. The method provides a limit of detection of the order of 1–4 μg, a relative standard deviation of the order of 0.4 to 2% for five independent measurements, and recovery percentage values from 99.8 till 103.6 %. A commercial sample of polyurethane paint solvent has been analysed by the developed procedure.

ISSN:0038-7010    

DOI:10.1080/00387019708006748

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor