Showing papers by "Jacques E. Guerchais published in 1975"
TL;DR: The structure of the title compound has been determined by the heavy-atom method from 1 265 reflections, measured with a diffractometer, and refined by full-matrix least-squares methods to R 0.042 as discussed by the authors.
Abstract: The structure of the title compound has been determined by the heavy-atom method from 1 265 reflections, measured with a diffractometer, and refined by full-matrix least-squares methods to R 0.042. Crystals are orthorhombic, space group Pnma, a= 14.91 (2), b= 16.38(2), c= 6.52(1)A, Z= 4. In the discrete molecules of the complex the antimony atom lies 0.29 A below the basal plane of a distorted square pyramid. The apical Sb–F distance [1.905(5)A] is shorter than the basal Sb–F distances [1.968(6)A]; basal Sb–O(ligand) distances are 2.305(5)A. There is only weak hydrogen bonding involving the water molecule of crystallisation.
14 citations
TL;DR: The structure of the title compound has been determined by the heavy-atom method from 530 reflections, measured with a diffractometer as mentioned in this paper, and refined by full-matrix least-squares methods to R 0.046.
Abstract: The structure of the title compound has been determined by the heavy-atom method from 530 reflections, measured with a diffractometer. and refined by full-matrix least-squares methods to R 0.046. Crystals are orthorhombic, space group Ama2, a= 7.36(1), b= 14.77(2), c= 6.88(1)A. In the structure uranium atoms are linked by di-µ-fluoro-bridges into zigzag chains with U–F 2.33 A. The pentagonal bipyramidal co-ordination of the metal atoms is completed by two oxygen atoms in apical positions (U–O 1.74 A) and by the oxygen atom of the dimethyl sulphoxide ligand (U–O 2.35 A) in the fifth equatorial position.
9 citations
TL;DR: In this article, the authors propose a stereochimie de l'anion a l'etat solide et en solution for β-dicetones symetriques.
Abstract: Resume Des oxochloro(dicetonato)niobates(V) ont ete isoles avec le cation tetraethylammonium. Leur formule generale est {(C 2 H 5 ) 4 N} {NbOCl 3 - (R-CO-CH-CO-R′)}. A l'aide de diverses methodes physiques on propose la stereochimie de l'anion a l'etat solide et en solution. Pour les β-dicetones symetriques ( R = R ′ = CF 3 et R = R ′ = CH 3 ) a l'aide des spectres de RMN on met en evidence la non equivalence des deux groupements CH 3 ou CF 3 , confirmant ainsi l'effet “trans” de la liaison multiple (NbO).
5 citations