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21.
We investigate the incidence matrix of a finite plane of ordern which admits a (C, L)-transitivityG. The elation groupG affords a generalized Hadamard matrixH=(h
ij
) of ordern and an incidence matrix for the plane is completely determined by the matrixR(H)=(R(h
ij
)), whereR(g) denotes the regular permutation matrix forgG. We prove that in the caseR(H) is symmetric thatG is an elementary abelian 2-group or elseG is a nonabelian group andn is a square. Results are obtained in the abelian case linking the roots of the incidence matrixR(H) to the roots of the complex matrix (H), a nontrivial character ofG. 相似文献
22.
Bankim C. Das I. Dey G. Biswas R. Banerjee Y. Iitaka A. Banerjee 《Journal of chemical crystallography》1993,23(6):509-512
The crystal structure of C6H16N8O2·CuCl2, a biguanide metal complex, has been determined by X-ray diffraction data using MoK radiation. The compound crystallizes in the monoclinic space groupP21/a, witha=11.074(4),b=12.061(4),c=5.312(3)Å and=102.8(1)°.The structure was solved by direct methods and refined by full-matrix least-squares to a finalR value 0.037 with 1245 unique reflections. The complex molecule is centrosymmetric, with the Cu atom (0.5,0.5,0.5) on a crystallographic center of symmetry. The complex molecule is rhombic planar with a trans configuration. 相似文献
23.
24.
Arylazoimidazoles (2) are N,N-chelating ligands. The polymerization trend of the azolate system is restricted via N(1)-benzylation. The parent molecules (2), N(1)-benzylated products (3) and palladium complexes (4) were made by standard methods. The ligands (3) and complexes (4) are new. They have been characterized by elemental analysis, i.r., u.v.-vis. and high resolution 1H-n.m.r. spectral data. Redox studies were carried out by cyclic voltammetry. On complexation, azo reduction is shifted anodically. 相似文献
25.
Summary In this paper we have reported our results on the attempted separation of copper(II), nickel(II), cobalt(II) and iron(III) in mixtures by filter paper strip chromatography, using aqueous ethanol as solvent. The effect of the presence of varying concentrations of citrate ion as a complexing agent in the mixtures has been studied. The complexing agent has been added in the metal solution, and not in the solvent as usually done by previous workers. 相似文献
26.
The reaction between trimethyltin bromide and silvermetaboratc leads to the formation of trimethyltin metaborate, (CH3)3SnBO2, and AgBr. The properties of the isolated new trimethyltin metaborate have also been studied. U.V. and I.R. spectra of (CH3)3SnBO2 has also been recorded. 相似文献
27.
Reliable N-alkylations of secondary amines have been developed. By using DIAD and TPP (or PS-TPP) a variety of secondary amines can be converted to the corresponding tertiary amines in good to excellent yields with diverse alkylhalides; no formation of quaternary amine salts are observed. These protocols are amenable to combinatorial chemistry libraries, and are also useful for the syntheses of secondary amines by an acid lysis of the cleavable tertiary amino resins. 相似文献
28.
A simple and inexpensive method for immobilizing alpha-amylase from Bacillus circulans GRS 313 on coconut fiber was developed. The immobilization conditions for highest efficiency were optimized with respect to immobilization pH of 5.5, 30 degrees C, contact time of 4 h, and enzyme to support a ratio of 1:1 containing 0.12 mg/mL of protein. The catalytic properties of the immobilized enzyme were compared with that of the free enzyme. The activity of amylase adsorbed on coconut fiber was 38.7 U/g of fiber at its optimum pH of 5.7 and 48 degrees C, compared with the maximum activity of 40.2 U/mL of free enzyme at the optimum pH of 4.9 and 48 degrees C. The reutilization capacity of the immobilized enzyme was up to three cycles. 相似文献
29.
Summary Xylenol orange reacts very sensitively with gallium(III), indium (III) and thallium(III) to form reddish violet colored chelates having max 560 nm in case of Ga and In and max 590 nm in case of Ti at PH 4.0. The molar ratio for all the chelates is 1 1 (metal reagent). Optimum conditions including the range for adherence to Beer's law, effect of PH on the color intensity, effect of excess reagent, and sensitivity are reported for the photometric determination of these metal ions using Xylenol orange.
Zusammenfassung Xylenolorange reagiert sehr empfindlich mit Gallium(III), Indium(III) und Thallium(III) unter Bildung rötlich-violetter Chelate mit einem Absorptionsmaximum bei 560 nm im Falle von Ga und In bzw. 590 nm für Tl bei pH 4,0. Das Molverhältnis ist in jedem Fall 11. Die besten Arbeitsbedingungen, der Gültigkeitsbereich des Beerschen Gesetzes, der Einfluß des PH auf die Farbintensität und des Reagensüberschusses sowie die Empfindlichkeit werden für die photometrische Bestimmung der genannten Ionen angegeben.相似文献
30.
Brajagopal Samanta Joy Chakraborty C. R. Choudhury S. K. Dey D. K. Dey S. R. Batten P. Jensen Glenn P. A. Yap Samiran Mitra 《Structural chemistry》2007,18(1):33-41
We have reported herein the synthesis of three new Cu(II) complexes of tri- and tetradentate Schiff base ligands containing
N3 or N4 donor set along with terminal NNN− or SCN− ligands: [L1Cu(NCS)]ClO4 (1), [L2Cu(NCS)2] (2) and [L3Cu(NNN)]ClO4 (3) [L1 = NC5H4C(CH3)=N(CH2)3N=C(CH3)C5H4N, L2= Me2N–(CH2)3–N=C(CH3)C5H4N and L3 = NC5H4CH=N–(CH2)4–N=CHC5H4N]. The complexes have been systematically characterised by elemental, spectroscopic and electrochemical techniques. Antimicrobial
activities of the Schiff base ligands and their metal complexes have been studied using the disc diffusion method on the strains
of Candida tropicalis and Bacillus megaterium. Structures of all the complexes have been unequivocally established from single crystal X-ray diffraction analyses that
show the monomeric units containing a five-coordinated copper center in highly distorted square pyramidal geometry with thiocyanate
or azide anion coordinated as terminal ligand. The complexes 1 and 3 crystallise in monoclinic (P21/c) and 2 in triclinic (P-1) space group, respectively. 相似文献