摘要:

Electron paramagnetic resonance spectra of cobalt and copper complexes of ethanolamines is studied at −110 and 25°C. The g values are determined. The magnetic susceptibilities of the cobalt, nickel and copper complexes are measured in the 4.2 − 293°K temperature range. The Curie - Weiss constant, , values proved that M-M Interactions appeared In the cobalt and copper complexes and didn't appear in the nickel complexes.

ISSN:0038-7010    

DOI:10.1080/00387019808003270

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Methylene blue dye binding heparin is not affected by pH among 2 and 12. Dye binding requires a macromolecular form with both carboxyl and sulfate-rich groups. The carboxyl groups without sulfate groups give no responses. The binding behavior is attributed to electrostatic attractions and Van der waals forces. Assay interference by base, SDS, and other compounds is explained in terms of the effect upon the equilibria between methylene blue and heparin.

ISSN:0038-7010    

DOI:10.1080/00387019808003271

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The enantiomeric composition and absolute configuration of 4-Amino-3-(benzo[b]furan-2-yl)-Butanoic Acids and of 4-Amino-3-(thien-2-yl)-Butanoic Acids 1 may be accurately determined by1H and13C nuclear magnetic resonance analysis of the corresponding derivatives 3 prepared by reaction with chiral reagents. Correlation with HPLC is signaled.

ISSN:0038-7010    

DOI:10.1080/00387019808003272

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

FT-IR Spectroscopy have been used for identifying both the structure of BN and the intensity of the compressive stress in cubic boron nitride (c-BN) film prepared by a unbalanced of (13.56 MHz) magnetron sputtering of a hexagonal boron nitride target in a mixture argon and nitride discharge. A T(temperature) - V(negative bias) phase diagram was obtained using the phase structure identify by IR spectra. Comparing the reflection infrared spectra (RIR) with the transmission infrared spectra (TIR) measured from same c-BN film, it is firstly found that RIR peak position of c-BN is lower than TIR peak position of c-BN, this means that the compressive stress on the surface layer of c-BN film is smaller than that inside c-BN film, may be this is the reason why thicker c-BN film can not be synthesized. A higher IR peak position of 1064 cm−1and a lower peak position 1004.7 cm−1were detected from a broken and partly peeled off c-BN film. The peak position of 1064 cm−1agrees with that of bulk c-BN at 1065 cm−1which was synthesized at high temperature and high pressure, while the peak position of 1004.7 cm−1accords well with the result calculated (1004 cm−1) by Wentzcovitch and it may be closes to that of the stress free value of c-BN. Using the result measured by Ulrich, the shift rate of IR peak position of c-BN in the films is about 3.8 cm−1/Gpa to be obtained.

ISSN:0038-7010    

DOI:10.1080/00387019808003273

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The unfolding of soybean lipoxygenase-1 during urea denaturation has been followed by activity assays and fluorescence measurement. The presence of stable intermediates during unfolding for both ferrous and ferric forms of lipoxygenase-1 were observed. In the presence of 6.0 M urea, the unfolding of soybean lipoxygenase-1, as monitored by fluorescence intensity, is a triphasic process, while the inactivation of the enzyme shows a single-phase kinetics. The rate constant of inactivation is consistent with that of the fast conformational change of the enzyme. Based on these, a minimal scheme containing two intermediates was proposed tointerpretthe unfolding of lipoxygenase-1 induced by urea.

ISSN:0038-7010    

DOI:10.1080/00387019808003274

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Five simple and accurate methods are presented for the determination of terazosin (TZ) in tablets. These methods are based on: the direct measurements of the first and second derivative spectra of samples (A), the reaction of TZ with chloranil (CH) in aqueous solution of pH 9 to give an intense yellow color measured at 340 nm (B), the reaction of the drug with mercurochrome (MER) in aqueous alkaline medium to give an intense red color measured at 543 nm (C), the formation of an ion-pair salt between the drug and bromocresol purple (BCP) with subsequent absorbance measurements at 412 nm (D), and a sensitive fluorimetric method (E). The latter method was extended to determine TZ in presence of its degradation products.

ISSN:0038-7010    

DOI:10.1080/00387019808003275

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

By using the product operator technique, analytical description of multipulse NMR experiments can be made. 2D DEPT J-resolved NMR spectroscopy is obtained by combining DEPT and 2D J-resolved NMR spectroscopy. In this study, the analytical description of heteronuclear 2D DEPT J-resolved NMR spectroscopy for a weakly coupledISn(I= 1/2,S= 1,n= 1,2,3) spin system is presented and experimental suggestions for13C 2D DEPT J-resolved NMR spectroscopy of deuterated molecules have been made.

ISSN:0038-7010    

DOI:10.1080/00387019808003276

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

One of the major product from the photodimerization of 2-[2-(2-methyl-phenyl)ethenyl)]naphtho[2. 1-b]furan (1) is a new fused cyclobutane-naphthofuran derivative, 6-(2-methylphenyl)-1-[2-(2-methylphenyl)ethenyl]-7-(2-naphtho-[2,1-b]furyl)-3-[2,1]naphtho-2-oxabicyclo[3.2.0]hept-3-ene (2). Its1H and13C NMR spectra were fully assigned by the application of COSY, LR COSY, NOESY, APT and HETCOR experiments in deuterated chloroform, acetone and benzene solutions.

ISSN:0038-7010    

DOI:10.1080/00387019808003277

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The infrared and electronic spectra of twelve amphiphilic complexes of N-hexadecyl-8-hydroxy-2-quinoline carboxamide (HL) have been investigated. In IR spectra a linear relationship between the v (C-O) frequency in C-O-M bond of the complexes and the relative atomic weight of the central metal ions and a linear relationship between the v (C-O) frequency and the ionization potential of the central metal (M →M2+(g)+2e) were obtained. These complexes appeared to fall into two groups. One is the complexes of closed-shell metal ions such as Ca(II), Mg(II), Zn(II), Cd(II), Al(III), La(III) and Gd(III) ion, the other is the complexes of transitional metal ions such as Mn(II), Co(II), Ni(II) and Cu(II) ion. All these complexes can form stable monolayer and can be deposited as uniform LB films.

ISSN:0038-7010    

DOI:10.1080/00387019808003278

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The present paper deals with the Photoacoustic (PA) studies of mono-substituted (hydroxy) naphthalene molecules, namely 1-naphthol and 2-naphthol in boric acid glass in the region 250–400 nm. The electronic transitions of these molecules observed experimentally, have been interpreted using the optimised geometries and CNDO/S-CI method. Assignments of observed electronic transitions are made on the basis of singlet-singlet and singlet-triplet transitions. The PA spectra of 1-naphthol and 2- Maphthol are compared with its parent molecule i.e. naphthalene molecule, in terms of charge transfer character of -OH group and polarization of molecules. It is observed that the non-radiative transitions in mono-substituted naphthalene molecules shift towards the higher wavelength region when compared with naphthalene molecule, which may be attributed to increase in the charge density in the substituted ring.

ISSN:0038-7010    

DOI:10.1080/00387019808003279

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor