Yves Dusausoy

Structure cristalline et configuration relative d'un complexe du titanocene presentant une chiralite plane et une chiralite centree sur l'atome de titane

Abstract The crystalline structure of the racemic form m.p. 164° C of the compound ( h 5 -3-MeC 5 H 3 C(Me 2 )C 6 H 5 )( h 5 -C 5 H 5 )Ti (2,6-Me 2 C 6 H 3 O)Cl has been determined by X-ray diffraction to establish the relative configuration of the two chiral moieties. This compound may be used further as a reference for studies on dynamic stereochemistry around the titanium atom. A systematic absolute nomenclature is proposed for this type of structure.

Structure cristalline et proprietes du dichlorure de bis(pentahapto-benzylcyclopentadienyl)zirconium triboluminescent

Abstract The product ( n 5 -C 5 H 4 CH 2 C 6 H 5 ) 2 ZrCl 2 is orthorhombic: a 12.05(1), b 24.12(2), c 6.99(1) A; space group Aba 2, Z 4. Final R 0.077. The Zr atom is tetrahedrally coordinated by two ZrCl σ bonds and two ZrCp π bonds. The crystal is tri-boluminescent and highly piezoelectric.

Distribution and Topology of the Electron Density in an Aluminosilicate Compound from High-Resolution X-ray Diffraction Data: the Case of Scolecite

The experimental electron density distribution in scolecite, CaAl2Si3O10.3H2O, has been derived from single-crystal high-resolution Ag Kα X-ray diffraction data. A statistical method based on the prediction matrix has been used to discuss the estimation of the valence populations (Pval) in the kappa least-squares refinements. The densities on the Si—O—Si and Si—O—Al bridges have been characterized using the topology of the electron density through its Laplacian at the bond critical points. The Si—O and Al—O bond features are related to the atomic environment and to the Si—O—T geometries (T = Si, Al).

Recherches dans la série des métallocènes : XXVIII. Action des réctifs de grignard sur les cétones benchrotréniques chirales

Abstract Benchrotrenyl chiral ketones beating an inductive group (CH 3 or OCH 3 ) were treated with Grignard reagents. The percentage of the diastereoisomeric tertiary alcohols obtained in each case depends on the natures of the inductive group and the benchrotrenyl ketone. In some cases the yield consists mainly or solely of the two secondary alcohols, obtained via reduction process. The structure of the alcohols is established by either spectroscopic or crystallographic means. Models complying with the observed stereoselectivity are proposed in each case.

Pseudoasymetrie dans la serie du benchrotrene I. Synthese des trois glycols ortho-substitues (OC)3CrC6H4(CHOHCH3)2

Abstract The three stereoisomeric glycols (CHOHCH 3 ) 2 C 6 H 4 Cr(CO) 3 have been prepared via 1,2-diformyl- and 1,2-diacetyl-benchrotrenes. The racemic (pseudosymmetric) form and the two meso (pseudoasymmetric) forms of the glycols have been identified by chemical derivatization and analysis of the spectroscopic data. The photochemical decomplexation of these glycols is a specific route for the preparation of the two corresponding benzenic glycols. The stereoselectivity which has been observed in some reactions is discussed.

Syntheses, structures, and bonding of heteropentametallic clusters [MCo3(CO)12{µ3-M′(EPh3)}](M = Fe or Ru; M′= Cu or Au; E = P or As): X-ray crystal structures of [RuCo3(CO)12{µ3-M′(PPh3)}](M′= Cu or Au)

The cluster anions [MCo3(CO)12]–[M = Fe (1) or Ru (2)] react with [{Cu(PPh3)Cl}4] in toluene to give the neutral pentametallic clusters [FeCo3(CO)12{µ3-Cu(PPh3)}](3) and [RuCo3(CO)12{µ3-Cu(PPh3)}](4). The latter two products react with PPh3 to give the ionic cluster species [Cu(PPh3)3][MCo3(CO)12]. The pentametallic cluster [RuCo3(CO)12{µ3-Au(PPh3)}](5), obtained by reaction of (2) with Au(PPh3)Cl in diethyl ether-toluene, also reacts with PPh3 to give [Au(PPh3)2][RuCo3(CO)12]. The structures of (4) and (5) have been determined by X-ray methods. Crystals of (4) are monoclinic, space group P 21/m, with Z= 2 in a unit cell of dimensions a= 9.122(3), b= 15.010(6), c= 12.580(7)A, and β= 107.86(3)°. Crystals of (5) are monoclinic, space group P21/c, with Z= 4 in a unit cell of dimensions a= 8.921 (3), b= 14.165(2), c= 26.72(1)A, and β= 91.95(4)°. The structures have been solved from diffractometer data by Patterson and Fourier methods and refined by full-matrix least-squares to R= 0.049 and 0.058 for 1 329 and 1 994 observed reflections, respectively. Both structures consist of a trigonal bipyramid of metal atoms with the cobalt atoms occupying the triangular equatorial plane and the copper or gold and ruthenium atoms situated at the apices. Three carbonyl groups bridge the Co–Co edges; the other nine are terminal, three attached to the Ru atom and two to each Co atom. Similarities in the bonding relationships of (4) and (5) are analyzed and rationalized through extended Huckel calculations.

Complexes organometalliques a liaisons metal—metal : XIII. Preparation de clusters heterotetrametalliques platine—molybdene et platine—tungstene et structure cristalline de Pt2Mo2(η5-C5H5)2(CO)6[P(C2H5)3]2

Abstract The cluster compounds Pt2M2(η5-C5H5)2(CO)6L2 (M  Mo, W; L  PEt3, PPh3) have been prepared from cis-PtCl2L2 and NaM(CO)3Cp. They are characterized by a planar, triangular, centrosymmetric arrangement of the metal atoms and by strongly asymmetric carbonyl bridges, which is shown by the crystal structure determination of Pt2Mo2(η5-C5H5)2(CO)6(PEt3)2.

Problems de stereochimie dynamique en serie du titanocene ☆: II. Stereochimie dynamique de reactions déchange de ligands σ-lies

Two ligand exchange reactions at the titanium atom in quasi-tetrahedral titanocene complexes have been studied. The first is substitution of a Cl ligand by an aryloxy group starting from substrates η5-Cp-η5-Cp′Ti(Cl)OPh which have an planar chirality on the Cp′ ring. The second is the substitution of one of the aryloxy groups of the complexes η5-Cp-η5-Cp′Ti(OPh′)OPh by the action of HCl. In this case, the reaction is generally selective and has a high degree of stereo-specificity with retention at the titanium atom. This retention has been established by crystallographic analysis of two suitable substrates: diastereoisomer F. 171°C of η5-C5H5[η5-(1-Me-3-CHMe2C5H5)](2-ClC6H4O)(2,6-Me2C6H3O)Ti and diastereoisomer F. 134°C of η5-C5H5[η5-(1-Me-3-CHMe2C5H3)](2-ClC6H4O)TiCl.

Etude de la condensation du fer pentacarbonyle et du fer nonacarbonyle sur le benzo[b]thiophene dioxyde-1,1

Abstract The reaction of iron pentacarbonyl or iron nonacarbonyl with benzo[ b ]-thiophen-1,1-dioxide leads to two complexes: benzo[ b ]thiophen-1,1-dioxide tricarbonyliron and -tetracarbonyliron. The structures of products are determined by NMR and mass spectroscopy. That of benzo[ b ]thiophen-1,1-dioxide tetracarbonyliron is confirmed by X-ray spectroscopy.

Epitaxial growth of zeolite X on zeolite A and twinning in zeolite A: structural and topological analysis

Abstract Synthesis of large zeolite A and X crystals by a modified Charnell’s method led to the formation of twinned zeolite NaA crystals, overgrowth of NaX onto NaA and co-crystallization of another phase analysed by electron microprobe as a Na aluminosilicate but not yet identified. Single crystals of NaA have a perfect cubic habit with a 100 μm edge. Twinned crystals of NaA are of the same size and correspond to an intergrowth of two cubes like that found in twinned fluorite crystals. NaX single crystals are octahedral, 220 μm along the [100] direction. Based on the difference in morphology of A and X crystals, epitaxial growth of NaX zeolite on NaA was also clearly identified by scanning electron micrographs. The object of this contribution is to provide topological and structural information on the twinning and epitaxy.