27 research outputs found
An Accurate Determination of the Exchange Constant in Sr_2CuO_3 from Recent Theoretical Results
Data from susceptibility measurements on Sr_2CuO_3 are compared with recent
theoretical predictions for the magnetic susceptibility of the
antiferromagnetic spin-1/2 Heisenberg chain. The experimental data fully
confirms the theoretical predictions and in turn we establish that Sr_2CuO_3
behaves almost perfectly like a one-dimensional antiferromagnet with an
exchange coupling of J = 1700^{+150}_{-100}K.Comment: revised and reformatted paper with new title to appear in Phys. Rev B
(Feb.1996). 3 pages (revtex) with 3 embedded figures (macro included). A
complete postscript file is available from
http://fy.chalmers.se/~eggert/expsusc.ps or by request from
[email protected]
Historical biogeography of amphibian parasites, genus Polystoma (Monogenea: Polystomatidae)
Pulsed discharge emission detector — Application to analytical spectroscopy of permanent gases
Antibacterial and Antifugal Mono- and Di-substituted Symmetrical and Unsymmetrical Triazine-derived Schiff-bases and their Transition Metal Complexes
A new series of antibacterial and antifungal triazine-derived mono- and di-substituted (symmetrical and unsymmetrical) Schiff-bases and their cobalt(II), copper(II), nickel(II) and zinc(II) metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments and IR and electronic spectral measurements. IR spectra indicated the ligands to act as tridentate towards divalent metal ions via a trazine-N, the azomethine-N and, indole-NH and deprotonated-O of salicylaldehyde. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II) and Zn(II)complexes and square-pyramid for Cu(II) complexes. NMR spectral data of the ligands and their diamagnetic zinc(II) complexes well-define their proposed structures/geometries. Elemental analyses data of the ligands and metal complexes agree with their proposed structures/geometries. The synthesized ligands, along with their metal complexes were screened for their antibacterial activity against Escherichia coli, Bacillus subtillis, Shigella flexneri, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi and for antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies show the metal complexes to be more antibacterial/ antifungal against two or more species as compared to the uncomplexed Schiff-base ligands