ZfN: Search Results

1	Author	Henri Brunner1, ManfredM. Uschiol3, Thomas Neuhierl3, Bernhard Nuberb	Requires cookie*
	Title	Copper Complexes with the Ligand [Cp2MoH2]
	Abstract	The reaction of CuCl with [CP2M0H2] yields the complex [Cu(Cp2M oH2)2Cl]. An X-ray structure analysis shows that the coordination of the copper(I) ion by two [CP2M0H2] lig ands and the chloride ion is pseudo-trigonal planar. The hydride ligands were located by using difference Fourier methods. A manifold of reactions took place when an aqueous so lution of CUSO4 was treated with a solution of [Cp2M oH 2] in dichloromethane in a 1:2 molar ratio. The X-ray structure analysis established a polymeric structure of the complex [Cu(Cp2MoH2)2Cu(Cp2M oH2)S0 4 ]" with two different copper centers.
	Reference	Z. Naturforsch. 54b, 337—340 (1999); received September 25 1998
	Published	1999
	Keywords	Copper, Molybdenum, X-Ray Data
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	TEI-XML for	default:Reihe_B/54/ZNB-1999-54b-0337.pdf
	Identifier	ZNB-1999-54b-0337
	Volume	54

2	Author	Isabel Díaza, Vicente Fernández3, VitalyK. Belskyb, Jose Luis, M. Artínez0	Requires cookie*
	Title	Synthesis and Structural Study of the Thermochromic Compounds Bis(2-amino-4-oxo-6-methylpyrimidinium) Tetrachlorocuprate(II) and Bis(2-amino-4-chloro-6-methylpyrimidinium) Hexachlorodicuprate(II)
	Abstract	The compound bis(2-am ino-4-oxo-6-methylpyrimidinium) tetrachlorocuprate(II) 1 contains CuCU2-square-planar anions, and bis(2-am ino-4-chloro-6-m ethylpyrim idinium) hexachlorod-icuprate(II) 2 quasi-planar CU2CI62-anions. Both compounds show thermochromic behaviour. This phenomenon has been studied by X-ray crystallography at variable temperature, with the result that no major change is observed in the geometry o f the copper atom. Thus it is possible to assume som e influence o f the hydrogen bonds and o f the different geometries o f interme diate states on the color o f the compounds due to the modifications provoked in the L —>M charge transfer and in the energy o f the metal d-d transitions. Magnetic measurements o f the compounds give information on magneto-structural correlations. Compound 1 is ferromagnetic (Tc = 20 K) due to the perpendicular arrangement o f the square anions that allows exchange pathways only via Cu-Cl -Cu , H-bonding or cationic n electron interactions. Compound 2 shows a very complicated behavior at low temperature with local antiferromagnetic fluctua tions. Crystal data: 1 CioHioNftC^CUCu, triclinic, P i; 393(2) K: a = 11.053(2), b = 11.334(2), c = 14.038(3) (Ä), a = 95.76(3), ß = 101.35(3), 7 = 9 0 .1 5 (3) 0 ; 293(2) K: a = 11.022(2), b = 11.289(2), c = 14.001(3) (A), a = 95.86(2), ß = 101.34(2), 7 = 9 0 .0 9 (3) 0 ; 155(2) K: a = 11.008(2), b = 11.231 (2), c = 13.967(3) (A), a = 95.86(2), ß = 101.37(2), 7 = 8 9 .9 9 (2) 0 ; Z = 4. 2 (C5H7N 3C l3Cu)2, monoclinic, P 2,/c; 293(2) K: a = 5.998(1), b =18.669(4), c = 9.466(2) (A), ß = 1 0 0 .9 3 (3)0 ; 150(2) K: a = 5.971(1), b = 18.655(4), c = 9.3 8 3 (2) (Ä), ß = 1 0 1 .6 4 (1) 0 ; Z = 4.
	Reference	Z. Naturforsch. 54b, 718 (1999); received March 1 1999
	Published	1999
	Keywords	Thermochromic Compounds, Copper, Chloride
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	TEI-XML for	default:Reihe_B/54/ZNB-1999-54b-0718.pdf
	Identifier	ZNB-1999-54b-0718
	Volume	54

3	Author	M. Ciscato3 ', J. Vangronsveldb, R. Valcke3	Requires cookie*
	Title	Effects of Heavy Metals on the Fast Chlorophyll Fluorescence Induction Kinetics of Photosystem II: a Comparative Study
	Abstract	The effects of toxic concentrations of Cu, Zn and Cd on the fast induction kinetics of fluorescence from photosystem(PS)II were investigated in a comparative way. The fast fluo rescence transient from primary leaves of m etal-treated bean plants was studied. During several days after metal application, the time course of the changes induced by the different metals was monitored. The results evidenced not only a different time course of the changes in fluorescence related parameters for the three metals, but also different effects on the fluorescence induction kinetics, which could possibly be linked to different mechanisms of action of the metals.
	Reference	Z. Naturforsch. 54c, 735 (1999); received November 8 1998/M arch 10 1999
	Published	1999
	Keywords	Cadmium, Chlorophyll Fluorescence, Copper, Heavy Metals, Zinc
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	TEI-XML for	default:Reihe_C/54/ZNC-1999-54c-0735.pdf
	Identifier	ZNC-1999-54c-0735
	Volume	54