| 1 | Author
| Mit Komplexe, KupferUnd Mangan, Zink, CarstenO. Kienitz, Carsten Thöne, PeterG. Jones | Requires cookie* | | Title
| Zur Koordinationschemie des 2,2'-Dipyridyldiselenids (PySeSePy), Teil 2 [1]  | | | Abstract
| The coordination chemistry of 2,2'-dipyridyldiselenide (PySeSePy) towards mangane se, copper and zinc centres has been studied. The complexes [MnBr2-/V,/V'-(PySeSePy)] (1), [CuBr2-/V,/V'-(PySeSePy)] (2), [Cu-(//-Br)-7V(/V'-(PySeSePy)]2 (3), [Cu-()U-Br)-{p-N,N'-(PySeSePy)}]" (4), [Cu-(/i-Cl)-/V,W'-(PySeSePy)]2 (5), [Zn(OOCC6F5)2-/V,/V'-(PySeSePy)] (6) and [Z n (0 S 0 2CF3)2-./V>/V'-(PySeSePy)] (7) have been synthesised and the crystal structures of 1, 3, 4 and 6 determined. 1, 3 and 6 display seven-membered metallacycles with tetrahedral coordination of the metal centres. In these cases 2,2'-dipyridyldiselenide acts as a chelating ligand. In the polymeric complex 4, 2,2'-dipyridyldiselenide acts as a bridging ligand. All com plexes display selenium-selenium single bonds with an average length of 232 pm. In contrast to the analogous chloro and nitrato complexes, the zinc complexes 6 and 7 are not dissociated in solution, as evidenced by 77Se NMR experiments. The corresponding resonances are shifted downfield in comparison with the ligand. | | |
Reference
| Z. Naturforsch. 55b, 587—596 (2000); eingegangen am 3. März 2000 | | |
Published
| 2000 | | |
Keywords
| Manganese, Copper, Zinc | | |
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| default:Reihe_B/55/ZNB-2000-55b-0587.pdf | | | Identifier
| ZNB-2000-55b-0587 | | | Volume
| 55 | |
2 | Author
| J.Nomssi Nzali, W. Hoyer | Requires cookie* | | Title
| X-ray Investigations of Liquid Bismuth-Copper Alloys  | | | Abstract
| Liquid copper, bismuth, and eleven bismuth-copper alloys were investigated at temperatures above the liquidus with X-ray diffraction. The experimental procedure was adjusted to reduce the effects of evaporation. The Faber-Ziman total structure factors S(Q) feature a splitting of the first maximum and negative values for Q around 1 A -1 in a large concentration range. The results are compared to previous neutron diffraction results by Zaiss and Steeb, to square-well potential model calculations by Gopala Rao and Satpathy and to a simple segregation model. The segregation model reproduces the features qualitatively. Partial structure factors are assessed by fitting both neutron and X-ray scattering results with reverse Monte-Carlo simulation. | | |
Reference
| Z. Naturforsch. 55a, 381—389 (2000); received May 29 1999 | | |
Published
| 2000 | | |
Keywords
| Bismuth, Copper, Liquid Alloys, X-ray Diffraction, Microsegregation | | |
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| | | | TEI-XML for
| default:Reihe_A/55/ZNA-2000-55a-0381.pdf | | | Identifier
| ZNA-2000-55a-0381 | | | Volume
| 55 | |
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