Roland Rösler

THE FIRST ORGANOBISMUTH RINGS : (RBI)3 AND (RBI)4, R = (ME3SI)2CH

Surprisingly facile at low temperatures is the synthesis of the first cyclobismuthanes 1 and 2 [Eq. (1)]. In solution 1 and 2 are in equilibrium. The four-membered ring 2 forms black crystals, which were structurally analyzed. At room temperature the rings decompose to elemental bismuth and R3 Bi. R=(Me3 Si)2 CH.

Solution and solid state structural investigations of organotin(IV) compounds containing asymmetric imidodiphosphinato ligands. X-ray structures of R′′2Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Ph)

Abstract Organotin(IV) derivatives of the type R2Sn[(OPMe2)(OPPh2)N]2 (R=Me, Bun, Bz, Ph) were prepared by metathesis reactions between R2SnCl2 and the potassium salt of the imidodiphosphinic acid, in toluene. Me3SnCl and K[(OPMe2)(OPPh2)N] (1:1 molar ratio) in chloroform at room temperature gives Me3Sn[(OPMe2)(OPPh2)N], while the NMR studies indicate that the corresponding triphenyltin(IV) derivative disproportionates gradually in solution to give Ph2Sn[(OPMe2)(OPPh2)N]2. Attempts to grow crystals of the trimethyltin(IV) derivative also gives Me2Sn[(OPMe2)(OPPh2)N]2 as a redistribution product. The compounds were characterized by IR and multinuclear NMR spectroscopy. The crystal and molecular structures of R2Sn[(OPMe2)(OPPh2)N]2 [R=Me (1), Bun (2), Ph (4)] were established by X-ray diffractometry. The compounds exhibit similar spiro-bicyclic structures, with the tin atom as spiro atom and chelating ligands with the oxygen atoms of the similar OPR2 groups in trans positions. The coordination geometry around the central metal atom is octahedral, with CSnC and OSnO (trans) angles of 180°. No significant differences were noted in the length of the tinoxygen, phosphorusoxygen and phosphorusnitrogen bonds, respectively, in relation to the different organic groups attached to tin or phosphorus atoms in a ligand moiety. The solution and solid state structures of the title compounds are discussed comparatively.

DIE ERSTEN ORGANOBISMUTRINGE: (RBI)3 UND (RBI)4 (R =(ME3SI)2CH)

Uberraschend einfach verlauft die Synthese der ersten Cyclobismutane 1 und 2 [Gl. (1)], vorausgesetzt, die Reaktionstemperatur ist hinreichend niedrig. In Losung stehen 1 und 2 miteinander im Gleichgewicht. Der Vierring 2 bildet schwarze Kristalle, die strukturanalytisch untersucht wurden. Bei Raumtemperatur zerfallen die Ringe zu Bismut und R3Bi. R=(Me3Si)2CH.

New Aspects of the Syntheses and Molecular Structures of Me2SbSeSbMe2 and Related Compounds

The structures of bis(dimethylstibyl)chalcogenides have been studied by density functional theory calculations and gas electron diffraction.

The Molecular Structures and Conformational Preferences of Bis(dimethylstibyl)-Sulfane and -Tellurane, E(SbMe2)2, E = S or Te, Me = CH3, by Density Functional Theory Calculations and Gas Electron Diffraction

Density functional theory calculations on E(SbMe2)2, E = S or Te, Me = CH3, indicate that the equilibrium structures are syn-syn or near syn-syn conformers with overall C2v or C2 symmetry. The calculations further indicate the existence of syn-anti conformers about 4 kJ mol-1 (E = S) or 1 kJ m ol-1 (E = Te) above the equilibrium structure. G as electron diffraction data show that both conform ers are present in gaseous S(SbMe2)2, while the presence of the syn-anti conformer in gaseous Te(SbMe2)2 is uncertain. The Sb - S and Sb - Te bond distances are 241.4(4) and 278.1(3) pm, respectively, the valence angles of the synsyn conformers are

The molecular structure of dimethyltellurium dichloride by gas electron diffraction and ab initio calculations at the MP2 level

Abstract Ab initio calculations at the MP2 level and gas electron-diffraction data of (CH 3 ) 2 TeCl 2 show that the molecular structure is pseudo-trigonal bipyramidal with the two methyl groups occupying equatorial positions and the two Cl atoms axial positions. The bond distances are ( GED MP 2 ): TeC = 213.2(5)/214.6 pm, TeCl = 250.4(3)/261.8 pm and the valence angles ∠ CTeC = 97(5)° 97.6° ; ∠ ClTeCl = 170(2)° 170.8° .

COMPLEXES WITH CYCLO-SBN LIGANDS

The four membered organoantimony ring (tBuSb)4 (1) reacts with [(C5R5)Mo(CO)3]2, (R = H, Me) to form the tetrahedrane derivatives [(C5H5)Mo(CO)2’2Sb2 (2), (C5H5)Mo(CO)2Sb3 (3), [(C5Me5)Mo(CO)2]2Sb2 (4), and [(C5Me5)Mo(CO)2Sb3] (5). An organo antimony ring, (C5Me5)Mo(CO)3(tBu3Sb4) (6), is also formed. In the crystalline state both cyclo-Sb3 complexes, 3 and 5 are associated through close intermolecular Sb⋯Sb contacts to form supramolecular layers.