J. Meunier-Piret

Nouveaux complexes π-allyliques de trifluoracetato-molybdene ou - tungstene

Abstract The synthesis, physico-chemical propperties and crystal structure of two new isomorphous π-allyldicarbonyl (molybdenum or tungsten) trifluoroacetates, solvated by 1,2-dimethoxyethane, are reported. Pseudo-octahedral surrounding of the metal ion is formed by the coordination of two carbonyl ligands, of a bidentate molecule of diether lying in the square plane of the metal atom, and of a symmetrical π-allyl group and a monodentate trifluoroacetate counteranion, both ligands forming the out of plane apices.

Crystal and Molecular-structure of 1-aza-5-stanna-5-chlorotricyclo[3.3.3.01,5]undecane, a 2,8,9-tricarbastannatrane

Abstract 1-Aza-5-stanna-5-chlorotricyclo[3.3.3.0]undecane crystallizes in the space group P 6 3 . The unit cell, with a 8.435(3), c 9.243(2) A, V 569.5(3) A 3 , contains two molecules. The structure was refined to a final R value of 0.057. The molecules CISn(CH 2 CH 2 CH 2 ) 3 N belong to the point group 3, and the Sn, Cl and N atoms lie on the crystallographic 3-axis. The tin atom has a trigonal bipyramidal environment with the nitrogen and chlorine atoms in apical positions. The tin-nitrogen intramolecular interaction is 2.372(29) A.

Crystal and molecular structure of 1-AZA-5-STANNA-5-methyltricyclo[3.3.3.01,5]undecane.evidence for a transannular donor−acceptor interaction in a tetraorganotin compound

The compound 1-aza-5-stanna-5-methyltricylo[3.3.3.01,5]undecane crystallizes in the space group P21c. The unit cell, with a 7.700(1), b 9.289(3), c 16.296(5) A, V 1159.4(5) A3, β 95.89(2)°, contains four molecules. The structure was refined to a final R value of 0.042. The configuration of the tin atom is intermediate between a trigonal bipyramid and a tetrahedron. The intramolecular tin−nitrogen distance is 2.624 A.

1,2-bis(organostannyl)ethanes As Powerful Bidentate Lewis-acids - Crystal-structures of (ph2clsnch2)2.(me2n)2po and [ph3p=n=pph3][(ph2clsnch2)2.cl]

Abstract The synthesis of bis(organostannyl)ethanes of the types (Ph 2 XSnCH 2 ) 2 ( 1 , X = Ph; 2 , X = Cl; 3 , X = Br; 4 , X = I) and (Ph 2 XSnCH 2 ) 2 ( 5 , X = Br, 6 , X = I) is described. The compounds have been investigated by means of 1 H, 13 C and 119 Sn NMR spectroscopy. 2 reacts with HMPA, [Ph 3 P = N = PPh 3 ] + Cl − , and Ph 4 PBr, respectively, to give the 1/1 complexes (Ph 2 ClSnCH 2 ) 2 · HMPA ( 7 ), [Ph 2 ClSnCH 2 ) 2 · Cl] − [Ph 3 PNPPh 3 ] + ( 8 ), and [(Ph 2 ClSnCH 2 ) 2 · Br] − [Ph 4 P] + ( 9 ). The formation constant K a for 8 in CDCl 3 solution is 2260 M −1 . The structures of 7 and 8 have been determined by X-ray diffraction. That of 7 shows that the two tin atoms are pentacoordinate but are inequivalent as a result of having different coordination sphere; one tin atom is coordinated by the monodentate HMPA (SnO 2.255(3) A) whereas the other interacts with a bridging Cl (Sn(1); Cl(2) 3.000(1) A). In the anion of 8 , the bis(chlorodiphenylstannyl)ethane may be regarded as an unsymmetrical chelate ligand towards Cl(12) (Sn(1)-Cl(12) 2.83(1), Sn(2)-Cl(12) 2.70(1) A).

Crystal and molecular structure of {3-[t-butyl(phenyl)phosphino]propyl}dimethyltin chloride

Abstract {3-[t-Butyl(phenyl)phosphino]propyl}dimethyltin chloride crystallizes in the space group P 2 1 / a . The unit cell, with a 22.798(9), b 9.578(4), c 8.385(7) A, β 102.16(3)°, V 1789.9(26) A 3 , contains 4 discrete molecules. The structure was refined to a final R value of 0.040. The tin atom has a distored trigonal bipyramidal environment with the phosphorus and chlorine atom in axial positions. The tin-phosphorus intramolecular interaction distance is 3.078(2) A.

Organotin(iv) Compounds of 2-thiopyridine - Crystal and Molecular-structure of Dicyclohexyltin(iv) Bis(2-pyridylthiolate)

Dicyclohexyltin(IV) bis(2-pyridylthiolate), compound 1, crystallizes in the orthorhombic system, a = 16.448(3), b = 40.315(8) and c = 7.113(3). Its molecular structure is best described as a tetrahedron, based on the two carbon-tin and the two sulfur-tin bonds, which is however strongly distorted as a consequence of two weak additional nitrogen-tin bonds. Compound 1 and four other diorganotin(IV) bis(2-pyridylthiolates) are characterized by Mossbauer, H-1, C-13 and Sn-119 NMR spectroscopy, and by FAB mass spectrometry. Their in vitro antitumour activity against two human tumour cell lines, MCF-7 and WiDr is reported. The ID50 values found are comparable to those found for cis-platin, but deceptively higher than for many other diorganotin compounds.

Synthesis, spectroscopic investigation and molecular structure of pentacarbonyl-5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo[3.3.01,5]octanechromium(0)

The compound pentacarbonyl-5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo-[3.3.01,5]octanechromium(0) was prepared in good yield by the reaction of 5-t-butyl-5-aza-2,8-dithia-1-stannobicyclo[3.3.01,5]octane with Cr(CO)6 in THF under UV-irradiation. The crystal and molecular structure was determined from three-dimensional X-ray data. The crystals are monoclinic, space group P21/c. The unit cell, with dimensions a 14.963(9), b 10.026(5), c 13.565(5)A, β 114.68°(5), contains 4 molecules. The structure was solved by the Patterson-method. The full-matrix refinement with the 2734 independent reflexions gave a final R value of 0.034. The eight-membered ring adopts an asymmetric boat-boat conformation with a tin-nitrogen bond lenght of 2.40 A; the tin-chromium bond length is 2.62 A.

Synthesis, Crystal and Molecular-structure, and Dynamic Stereochemistry of Ch2[(c6h5)sn(sch2ch2)2nch3]2, a Compound With 2 5-coordinate Tin Centers

Abstract The crystal and molecular structure of CH 2 [(C 6 H 5 )Sn(SCH 2 CH 2 ) 2 NCH 3 ] 2 were determined by X-ray diffraction. Both tin atoms show approximate trigonal-bipyramidal coordination, but the two phenyl rings and the methylene bridge do not occupy the same sites around the two metal centers. The 1 H, 13 C, 119 Sn data at various temperatures and magnetic fields indicate the presence in the slow exchange region of three isomers. The observations are interpreted on the basis of the assumption that in solution the phenyl groups can occupy both equatorial positions, both axial positions or one axial and one equatorial position. The last combination which is observed in the solid state, corresponds to the major isomer in solution. The stereochemical correspondence between this system and six-coordinate cis -bis-chelate complexes of the type M(AB) 2 X 2 is outlined. In the fast exchange region the spectra show that only one residual isomer is present. These observations imply that in the main isomerization process the tin atoms rearrange independently of each other. The data indicate that this rearrangement proceeds through the dissociation-inversion mechanism previously discussed.

The Crystal and Molecular-structure and Sn-119 Nmr Investigations of 2,2,3,3,5,5,6,6-octaphenyl-2,3,5,6-tetrastannacyclohexane

Abstract The crystal and molecular structures of 2,2,3,3,5,5,6,6-octaphenyl-2,3,5,6-tetrastannacyclohexane were determined from three-dimensional X-ray data. The crystals are triclinic, space group P 1 . The unit-cell, with dimensions a 9.490(2), b 10.202(2), c 12.260(3) A, α 103.43(2), β 78.09(2), γ 93.06(2)°, contains one molecule. The structure was solved by the Patterson method and refined to a final R value of 0.032 for 3190 independent reflections. The tetrastannacyclohexane ring has a chair conformation. The tintin bond length is 2.78 A.

Crystal and molecular structure of 5-t-butyl-5-aza-2,8-dithia-1-stanna(II)bicyclo[3.3.01,5]octane. Identification of two different geometries along the dissociation-inversion pathway

Abstract The crystal and molecular structure of 5-t-butyl-5-aza-2,8-dithia-1-stanna(II)bicyclo[3.3.0 1,5 ]octane [Sn(SC 2 H 4 ) 2 NC 4 H 9 ] 2 have been determined from three-dimensional X-ray data. The crystals are monoclinic, space group P 2 1 / c , with cell dimensions: a 14.104(2), b 21.911(4), c 11.624(2) A, β 98.73(1)°, Z = 6. The final R is 0.040 for the 4279 observed reflections. The unit-cell contains four asymmetric dimers (dimer a ) and two centrosymmetric dimers (dimer b ), each dimer forms a four-membered Sn 2 S 2 ring in which the sulfur atoms are three-coordinated. The SnN distances in the two dimeric forms are significantly different (namely, 2.64 and 2.75 in dimer a , 2.97 A in dimer b ). The lengthening of the SnN distances involves the shortening of the bridging tin—sulfur bonds (2.99 and 2.79 in a , 2.71 A in b ). The coordination around the three different Sn atoms is hemispherical.