摘要:

AbstractThe matrix isolation technique with Fourier transform infrared detection has been applied to determine the products of gaseous radical reactions. The gas phase reactions were carried out in a discharge flow system and about 1% of the gas mixture was deposited onto a low temperature target through a pinhole. A differential pumping scheme was employed to maintain the pressure of the cryosystem below 10−5torrwhile that of the flow system was kept at about 2torr.Species including HO2(from the H+O2reaction), ClO2(from the Cl+O2reaction) and ClO (from the Cl+O3reaction) have been produced in the gas phase and were successfully trapped in matrices and detected with an FTIR spectrometer. In addition, both HCl and HOCl have been detected as the reaction products from the gaseous ClO+HO3reaction. The production of HCl from the ClO+HO2reaction may have a significant impact on catalytic ozone destruction in the atmospher

ISSN:0009-4536    

DOI:10.1002/jccs.198700025

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractWe have recently developed a modification of the traditional semiempirical INDO‐MO method especially useful for open shell problems: INDO withs‐pseparation (J. Chin. Chem. Soc., 32, 385(1985)). In order to show the reliability of our new method fifty seven free radicals and radical ions were selected as examples for our MO calculation.We are particularly interested in the unpaired electron distribution of hydrogen atoms. A linear correlation analysis between the spin density and the isotropic hyperfine coupling constant (aH) for1H has been carried out for these radicals and ions. Most of our calculatedaH's are better than the results reported using the conventional INDO met

ISSN:0009-4536    

DOI:10.1002/jccs.198700026

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe Mössbauer parameters of frozen solutions of 0.05MSn(H2O)(ClO4)2, Sn(H2O)3(ClO4)4, SnCl4·5H2O, SnBr4and Na2SnBr6[designated as Sn(H2O)N‐N, L(x‐N')+N, in whichN≤N;N' =N= 6 for SnBr2−6,N′=4 withN=6 for Sn(H2O)2(ClO44Sn(H2O)2Cl4and Sn(H2O)2Br4andN′=2 withN=3 for Sn(H2O)(ClO44)2] were found to be linearly related to the concentration (c) of perchloric acid. These facts were attributed to a change in activity of water (aw). Atc=O,aw=1, the Mössbauer parameters corresponded to Sn(H2O)z+N, whereas atc=11.6M(70%), they corresponded to the crystalline state of Sn(H2O)N‐N, L(z‐N)+N+. It was shown that even ClO−4ion could coordinate to tin atom in perchloric acid. The degree of association at any given c could be estimated very easily through the relation . It was emphasized that the activity of water should be taken into account when equilibrium studies were carried out in perchloric acid solutions. Further corrections for perchlorate complex formation should be made, if a very weak ligand was added into metal p

ISSN:0009-4536    

DOI:10.1002/jccs.198700027

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe interaction between the decadentate ligand triethylenetetraminehexaacetic acid (TTHA or H6Z) and tripositive rare‐earth metal ions (Ln3+) has been investigated. The acid formation constants of the hydrogen chelates (LnHZ2−, LnH2Z‐) and the formation constants of the normal chelates (LnZ3−) have been evaluated at 15, 25 and 35°C, and at an ionic strength of 0.1 (KNO3), the former by a titration method and the latter by a mercury indicator electrode technique. Enthalpy and entropy changes characterizing the formation of the normal chelates have been calculated at 25°C. These functions have been compared with corresponding values for related chelati

ISSN:0009-4536    

DOI:10.1002/jccs.198700028

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractN, N‐bis(pyrazol‐1‐ylmethyl)aminomethane (bpam) andN, N‐bis(3, 5‐dimethylpyrazol‐1‐ylmethyl)aminomethane (bdmpam) reacted with M(CO)6or M(CO)3(CH3CN)3in acetonitrile to give respectively fac‐(bpam)M(CO)3and fac‐(bdmpam)M(CO)3in good yields (M=Cr, Mo, W). These complexes are characterized by elemental analysis, IR, and NMR and compared with the related polypyrazolylborate complexes of the group V

ISSN:0009-4536    

DOI:10.1002/jccs.198700029

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractA novel spectrometer incorporating a multichannel detector for simultaneous multi‐element atomic emission spectrometry (AES) is described. The spectrometer consists of a multi‐bandpass optical filter comprised of a concave and a fiat grating in substractive mode, and a high resolution stage which utilizes an echelle grating and an one inch 1024‐channel photodiode array as the detector. Characterization with respect to the spectral resolution, the spectral response, and the capability of multi‐element detection demonstrated the systems's potential for simultaneous chemical analyses without moving any mechanical parts. To adjust the system for the analyses of different sets of elements, the corresponding mask is simply placed in p

ISSN:0009-4536    

DOI:10.1002/jccs.198700030

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractA differential pulse polarographic method for the determination of nitrate ion has been developed. With 0.5MCaCl2as supporting electrolyte, NO−3is reduced to give a peak withE1/2=–1.836 Voltvs. the Ag/AgCl electrode. The differential pulse polarographic peak height is proportional to the nitrate concentration from 20 to 60ppm. The detection limit for nitrate is 2ppmin pure aqueous solution. In the determination of 40ppmnitrate a relative precision (relative standard deviation) of less than 2% was achieved. Nitrite interferes seriously and should be absent if accurate results are required. The method has been applied to the determination of nitrate in Ammonium Uranyl Tricarbonate (AUT) Solution, results obtained by this method are compared to those obtained by ion chromatography. The agreement between the two sets of results suggests that the DPP method can be used with a fair degree of confide

ISSN:0009-4536    

DOI:10.1002/jccs.198700031

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractDeprotonation/methylation reactions have been carried out on a series of substituted 2‐sulfolenes and 3‐sulfolenes. For 2‐sulfolenes, both allylic and vinylic deprotonation reactions occur to give, after treatment with methyl iodide, 2‐methylated 3‐sulfolenes and 2‐methylated 2‐sulfolenes. These products are useful intermediates because substituted 3‐sulfolenes are precursors to substituted butadienes and 2‐alkylated 2‐sulfolenes are precursors to β‐functi

ISSN:0009-4536    

DOI:10.1002/jccs.198700032

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractTwo diterpenoids, (+)‐labda‐7,14‐dien‐13‐ol and (+)‐manoyl oxide, and onebis(bibenzyl) compound, isomarchantin C, were isolated as the major components from the Taiwanese liverwortMylia nuda. The spectral evidence is discussed in this paper. In addition, several monoterpenes and sesquiterpenes were also identifi

ISSN:0009-4536    

DOI:10.1002/jccs.198700033

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractKinetics of oxidation of 1‐phenylsemicarbazide (PSC) by peroxydisulphate ion (PDS) have been carried out where by the pseudo first order condition was verified at large excess of PDS concentration. The rate of the reaction was followed spectrophotometrically, The stoichiometry was found to be 1:1 where 1‐phenylazoformamide is the oxidation product. The effect of acidity on the rate of oxidation was investigated for different temperatures. The parameters of activationΔG*,ΔH* andΔS* were computed for both hydrogen ion depedent and hydrogen ion independent reaction pathes. A free radical mechanism was pr

ISSN:0009-4536    

DOI:10.1002/jccs.198700034

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY