Neues über Protein-Thiolgruppen und Disulfidbindungen

Eine der vom französischen Centre National de la Recherche Scientifique (CNRS) veranstalteten „Conferences Jacques Monod”︁ war dem Thema „Intracellular Redox Controls by Thioredoxin and Glutaredoxin Systems”︁ gewidmet. Zu der Konferenz kamen im Juli in der Biologischen Station Roscoff (Bretagne) etwa 100 Wissenschaftler aus 15 Ländern zusammen.     

Neues über Zweikernige Oxoferrate(II)

News about Binuclear Oxoferrates(II) [1] . By “reaction with the wall” of the Fe-cylinders used here we synthesized the new oxoferrates(II) Cs₆[Fe₂O₅], Cs_3.5Rb_2.5[Fe₂O₅] and Rb₄K₂[Fe₂O₅] in the form of red single crystals. The structure elucidation via four-circle-diffractometer data shows that the new oxoferrates(II) are isotypic with Cs₂(Cs_0.35K_1.65)K₂ [Fe₂O₅]. In the structure we have isolated binuclear groups [(O1)₂Fe—O(2)—Fe(O1)₂]^6?. Structure refinements is possible in the centrosymmetrial space group C2/m as well as in the space groups C2 and Cm without centre of symmetry. The existence of two further oxoferrates(II) Cs_6?xRb_x[Fe₂O₅] and Cs_6?xK_x[Fe₂O₅] which can be described as solid solutions was confirmed by power-data.     

Neues über Oxogermanate. 1. Zur Kenntnis von K4GeO4

News on Oxogermanates. 1. On K₄GeO₄ For the first time single crystals of K₄GeO₄ have been prepared by heating KO_0.46 and GeO₂. The structure has been refined. K₄GeO₄: 2565 I₀(hkl), four circle diffractometer PW 1100, ω-scan, AgKα, R = 0.0826, R_w = 0.0837, P1 ; a = 640.56(35), b = 633.87(34), c = 933.68(45) pm; α = 80.26(5)°, β = 107.58(5)°, γ = 113.63(4)°; d_x = 2.94 g/cm³; d_pyk = 2.91 g/cm³; Z = 2. K₄GeO₄ is isotypic with K₄SnO₄. There is, however, an essential difference of the C.P. (Coordination Polyhedra) with respect to K4 and O4. The Effective Coordination Numbers, ECoN, the Mean Fictive Ionic Radii, MEFIR, and the Madelung Part of Lattic Energy, MAPLE, are calculated.     

Neues über Oxouranate: Über α-Li6UO6. Mit einer Bemerkung über β-Li6UO6

New Investigations about Oxo Uranates: On α-Li₆UO₆. With a Remark about β-Li₆UO₆ The crystal structure of transparent, bright yellow single crystals of α-Li₆UO₆ has been determined. [a = 838.07(5), c = 738.34(7) pm; d_pyk = 4.02, d_x = 4.17 g · cm^?3; space group R3 ; Z = 3; R = 3.17%, R_w = 3.06%; 408 symmetry independent I₀(hkl); AgKα fourcircle diffractometer Philips PW 1100]. The structure is dominated by a threedimensional framwork of “hollow spaces”, built up by 12 O^2? (and 12 Li⁺). The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Schritte über Grenzen

“Research and Education in the Middle East” – Eine Tagung zum Problem der soziopolitischen Verantwortung der Wissenschaft.