Showing papers on "Compounds of zinc published in 1989"
TL;DR: In this article, the thermal properties of zinc compounds with picolinic acid, nicotinic acid and isonicotinic acids have been studied by thermogravimetry and differential thermal analysis.
26 citations
TL;DR: A test of the ability of extended X-ray absorption fine structure (EXAFS) to determine structural information with specific reference to zinc sites in enzymes has been made.
Abstract: A test of the ability of extended X-ray absorption fine structure (EXAFS) to determine structural information with specific reference to zinc sites in enzymes has been made. X-ray absorption spectra of 18 compounds of zinc have been measured and the nearest-neighbour scattering has been interpreted using a Fourier transform and an ab initio technique. Empirical Zn-N, Zn-O, Zn-S and Zn-Cl amplitude and phase functions have been extracted from Zn(C3H4N2)4(ClO4)2, ZnO, Zn(S2COC2H5)2 and [N(CH3)4]2[ZnCl4], respectively and tabulated as a function of the wavevector with respect to 9660.0 eV X-ray energy. These amplitude and phase functions were then tested with respect to the other 14 compounds. For a single species of atoms in the first coordination shell the interatomic distances can be established to +/- 0.5 pm (+/- 5 x 10(-3) A) whilst when mixed shells exist errors in distances are +/-4 pm (+/- 40 x 10(-3) A). Coordination numbers are given to +/- 16% for the single species case a and +/- 25% for the mixed coordination case. Using the theoretical amplitude and phase functions of McKale et al. [(1988) J. Am. Chem. Soc. 110, 3763-3768] the deduced distances are systematically too small by an average of 0.6 pm (6 x 10(-3) A). The errors in the coordination numbers are 18%.
12 citations
Patent•
05 Jun 1989
TL;DR: A process for the preparation of aromatic carboxylic acids or their salts comprises heating carboxyl-free aromatic compounds and aromatic acid salts whose basic structures differ from those of the aromatic compounds, or heating polycyclic aromatic compounds with three or more rings, under carbon dioxide pressure in the presence of one or more metal compounds selected from group (a) of compounds of zinc, cadmium, and thallium and (b) of compound of cesium, Group II metals, and Group III a metals to effect the intermolecular transfer of the car
Abstract: A process for the preparation of aromatic carboxylic acids or their salts comprises heating carboxyl-free aromatic compounds and aromatic carboxylic acid salts whose basic structures differ from those of the aromatic compounds, or heating polycyclic aromatic compounds with three or more rings and monocyclic or bicyclic aromatic carboxylic acid salts, under carbon dioxide pressure in the presence of one or more metal compounds selected from group (a) of compounds of zinc, cadmium, and thallium and one or more compounds selected from group (b) of compounds of cesium, Group II metals, and Group III a metals to effect the intermolecular transfer of the carboxyl groups.
1 citations
Patent•
05 Jun 1989TL;DR: A process for the preparation of aromatic carboxylic acids or their salts comprises heating carboxyl-free aromatic compounds and aromatic acid salts whose basic structures differ from those of the aromatic compounds, or heating polycyclic aromatic compounds with three or more rings, under carbon dioxide pressure in the presence of one or more metal compounds selected from group (a) of compounds of zinc, cadmium, and thallium and (b) of compound of cesium, Group II metals, And Group IIIa metals to effect the intermolecular transfer of the car
Abstract: A process for the preparation of aromatic carboxylic acids or their salts comprises heating carboxyl-free aromatic compounds and aromatic carboxylic acid salts whose basic structures differ from those of the aromatic compounds, or heating polycyclic aromatic compounds with three or more rings and monocyclic or bicyclic aromatic carboxylic acid salts, under carbon dioxide pressure in the presence of one or more metal compounds selected from group (a) of compounds of zinc, cadmium, and thallium and one or more compounds selected from group (b) of compounds of cesium, Group II metals, And Group IIIa metals to effect the intermolecular transfer of the carboxyl groups.