The crystal and molecular structure of oxo-bis[tribenzylsilicon(IV)]

Crystals of oxo-bis[tribenzylsilicon(IV)], O[(PhCH₂)₃Si]₂, are triclinic, space group P$\text{1}$, with a = 9.780(7), b = 9.938(9), c = 10.283(6) Å, α = 93.35(1), β = overall symmetry close to $\text{3}$: the SiOSi skeleton is strictly linear with SiO = 1.613(4) Å. The conformations of molecules and ions isoelectronic with O[(PhCH₂)₃Si]₂ are compared and discussed.     

The crystal and molecular structure of hexadecaphenyloctasiloxyspiro(9,9)titanate(IV)

The crystal and molecular structures of the title compound have been determined by single crystal X-ray diffraction methods. In the spiro molecule, the metal atom has a geometry very close to tetrahedral, with OTiO angles of 107.9–111.0(2)° and very short TiO bonds of length 1.777–1.791(5)Å. The two TiO₅Si₄ rings have different, ill-defined conformations; the SiO bond lengths and SiOSi angles are similar to those in (SiO)_n rings.     

Oxidation of the [Rh(CO)2Cl2] anion in aqueous solution

The reaction of rhodium(I) carbonyl chloride, [Rh(CO)₂Cl]₂, with dichromate, cerium(IV) sulfate, hexachloroplatinic acid or p-benzoquinone in aqueous hydrochloric acid proceeds by consumption of 4 equivalents of oxidizing agent per mole or rhodium(I) in accordance with the equation Rh^I(CO)₂  4e + H₂O → Rh^III(CO) + 2H⁺ + CO₂A “cyclic” oxidation mechanism is suggested.     

Silicon—carbon multiple-bonded (PPπPπ) intermediates : III. Reactions of thiobenzophenone with thermally generated 1,1-disubstituted 1-silaethenes, [R2SiCH2]: evidence for a PπPπ silicon—sulfur double-bonded species

Reactions of [R₂SiCH₂] (R  Me, Ph), generated by thermolysis of the corresponding 1,1-disubstituted silacyclobutane at 611°C, with Ph₂CS are described. A Wittig-like reaction takes place, yielding Ph₂CCH₂ and what are believed to be the first examples of transient [R₂SiS].     

The crystal and molecular structure of 1,1,1,3,3,3-hexaphenyl-1,3-disilapropane

Crystals of the title compound H₂C(SiPh₃)₂ are triclinic, space group P$\text{1}$, with a = 9.290(2), b = 12.128(4), c = 16.882(4) Å, α = 62.08(1), β = 106.88(1), γ = 117.28(2)° and Z = 2. The central skeletal angle SiCSi is 128.8(7)°. The structures of the molecules H₂C(SiR₃)₂ (R = H, CH₃, and Ph) are compared and discussed: a simple model for the skeletal geometry of species H₂C(MR₃)₂ is proposed, and tested against experimental data and theoretical calculations.     

Relative dioxygenation rates of some trans-Ir(CO)X(PR3)2 complexes: The effect of phosphine and halogen changes

Relative rates of dioxygen uptake by the complexes trans-Ir(CO)X(PPh₂R)₂ (R = Ph, Me, Et; X = F, Cl, Br, I) have been measured in dichloromethane and found to follow the order R = Ph<Et<Me and X = F <Cl<Br<I. The basicity of these trans-Ir(CO)X(L)₂ complexes, as measured by their affinity for dioxygen, is not reflected in the energy of the ν(CO) absorption in the parent compounds; a previous report that complex basicity ∝1/ν(CO) does not hold for the complexes reported here.     

The crystal and molecular structure of bis(triphenylsilicon) carbodiimide

The structure of (Ph₃SiN)₂C has been determined by single crystal X-ray diffraction. The structure was solved by direct methods and refined to R = 0.071 for 593 independent diffractometer data. The crystals are rhombohedral, R$\text{3}$ with a = b = c 18.201(20) Å, α = β = γ = 48.82(2)°, and Z = 4. The three crystallographically independent molecules each have linear SiNCNSi chains lying along the crystallographic threefold axes; in two of the molecules the central carbon atom lies on a centre of symmetry. Principal mean bond lengths and angles are: Si, 1.696(25); SiC, 1.846(20); NC, 1.164(30); CC, 1.387(14) Å; CSi, 108.2(6); and CSiC, 110.8(6)°.     

The crystal and molecular structure of oxo-bis[tribenzylgermanium(IV)]

Crystals of oxo-bis[tribenzylgermanium(IV)], O[(PhCH₂)₃Ge]₂, are rhombohedral, space group R$\text{3}$, having a = 9.621(2) Å, α = 85.48(3)°. The structure was solved by Patterson methods using diffractometer data and refined by full-matrix least squares to R = 0.0876. The structure consists of molecules lying along the 3-fold axis of the unit cell, in which the GeOGe fragments are strictly linear and centrosymmetric. The GeO distance is 1.730(1) Å and the GeC distance is 1.980(5) Å.     

Intramolecular metal—double bond interactions : VII. Intramolecular cyclization of alkenyl derivatives of lithium,aluminum, gallium and indium

The intramolecular cyclization reactions of tri-1-hex-5-enyl Group III derivatives and of 1-hex-5-enyllithium have been investigated and it is proposed that the reactions may be depicted as internal addition across the terminal double bonds of the alkenyl species. The cyclization reaction proceeds more readily for the 1-hex-5-enyl derivatives than for any other chain length and is dependent on temperature, concentration and solvent. ¹H NMR data and cryoscopic molecular weight data are presented for several diisobutyialkenyl- and diisobutylalkyl-aluminum derivatives. These data have been interpreted in terms of a direct intramolecular interaction between the metal center and the π-electron system of the olefinic site. The intramolecular cyclization reactions for the 1-hept-6-enyl, 1-oct-7-enyl- and 1-undec-10-enylaluminum derivatives also were investigated and it was found that cyclization occurred only for the 1-hept-6-enyl derivative.     

Organolanthanoids V. The crystal and molecular structure of DI-η5-cyclopentadienyl-1,2-dimethoxyethaneytterbium(II)

Crystals of di-η⁵-cyclopentadienyl-1,2-dimethoxyethaneytterbium(II) are mono-clinic, space group Cc, with a 9.25(2), b 23.49(5), c 8.23(2) Å, β 123.59(4)° and Z  4. The ytterbium ion is pseudo-tetrahedrally coordinated by two cyclopentadienyl groups and a bidentate 1,2-dimethoxyethane ligand, and there is no inter-molecular association. The sites of the cyclopentadienyl ligands are disordered.     

Complexes of organometallic compounds : XXXIX. synthesis,infrared and mössbauer studies on monoorganotin(IV) complexes with tridentate ligands

Novel complexes RClSntrid, where R is Me, Ph, n-Oct, and trid^2? are dianions of tridentate “planar” ligands with ONO and SNO donor atoms, were synthesized and investigated in the solid state by infrared and Mössbauer spectroscopy. Possible configurations are discussed; polymeric trigonal bipyramidal structures seem to occur, although five-coordinated monomers as well as octahedral dimers (via oxygen or sulfur bridges) are not excluded.     

Cationic organometallic complexes with hexaalkylborazines: I. Synthesis and reactivity of cationic hexamethylborazinerhodium complexes with carbonyl,ethylene and diolefins as ligands

The PF₆ salts of the new cationic hexamethylborazinerhodium(I) complexes of general formula [Rh(Me₃B₃N₃Me₃)(LL′)]⁺ (LL′= 1,5-cyclooctadiene, norbornadiene, tetrafluorobenzobarrelene, trimethyltetrafluorobenzobarrelene, L = L′ = ethylene, CO) have been prepared from the reaction between [RhCl(LL′)]₂, Me₃B₃NMe₃, and AgPF₆ in dichloromethane. These complexes are very labile, undergoing rapid ring ligand exchange in solution with σ and π-donor ligands. The synthesis of [Rh(η⁶-naphthalene)(COD)]PF₆ is also described. The properties and NMR and IR spectroscopic characteristics of the new compounds are briefly discussed.     

Alkylation reactions with organometallic compounds : IV. The reaction of tris(triphenylphosphine)methylcobalt with diphenylacetylene

Tris(triphenylphosphine)methylcobalt;(Ph₃P)₃CoCH₃, reacts with diphenyl-acetylene to give α-methylstilbene as the sole addition product.(Ph₃P)₃CoCH₃ can be used as an alkylation reagent in ethers or in aromatic solvents.     

Crystal and molecular structure of the tetrachloropalladate of the dication meso-3,7-diazonia tricyclo[4.2.2.22,5]dodeca-3,7,9,11-tetraen-4,8 diamine obtained by coupling reaction of 2-aminopyridines

A solution of trans-bis(2-aminopyridine)dichloropalladium(II) in DMF and HCl 2 N was left for several weeks. The compound isolated from this solution was identified by X-ray structural analysis as the tetrachloropalladate of meso-3,7-diazonia tricyclo[4.2.2.2^2,5] dodeca-3,7,9,11-tetraen-4,8 diamine, which contains a dication not previously described in literature. The organic dication is formed by two aminopyridine rings linked by CC bonds whose length is greater (1.61 Å) than a normal single CC bond.     

Crystal and molecular structure of 9-exo-(4-nitrophenyl)thio-10endo-chlorotricyclo[6.3.1.02,7]dodeca-2(7),3,5-triene

Crystal and molecular structure of 9-exo-(4-nitrophenyl)thio-10-endo-chlorotricyclo[6.3.1.0^2,7]dodeca-2(7),3,5-triene (I) was determined by X-ray diffraction analysis: space group P2₁/c, a=9.514(1), b=13.457(1), c=13.163(2) Å, β=104.72(1)°, Z=4, R=0.041 (CAD-4 automatic diffractometer, λCuK_α, 2747 independent reflections with I≥3σ). The framework of molecule I consists of three condensed rings: the benzene ring, the cyclopentene ring having an envelope conformation with a flap at the bridging C atom, and the cyclohexane ring having a distorted chair conformation. The-SAr and Cl substituents have a trans-diaxial orientation at the cyclohexane ring. Molecule I is sterically hindered; it has appreciably reduced interatomic contacts: Cl…C₂, Cl…C₇, S…C₁₂, etc.     

Reactions of collman complex with tin(IV) and germanium(IV) porphyris,formation of [tin(II) and germanium(II) porphyrins] tetracarbonyliron and crystal structure of [2,3,7,8,12,13,17,18-octaethylporphinato tin(II)] tetracarbonyliron

The action of Na₂Fe(CO)₄ with tin(IV) and germanium(IV) porphyrins affords metal(II) porphyrin complexes [(por)M(II)Fe(CO)₄] (por = porphyrinate, M - Sn(II) or Ge(II)). The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques. The molecular structure of [(oep)Sn(II)Fe(CO)₄] was solved by X-ray diffraction techniques : the Sn coordination is square pyramidal with the iron in axial position (Sn-Fe = 2.492(1)Å) whereas the Fe coordination is trigonal bipyramidal. Mössbauer parameters provide convincing evidence for the formal zero oxidation state of the iron atom.     

Organocobalt complexes IX. The insertion of acetylenes into butenolide complexes; crystal structure of a dicobalt complex with a novel five-carbon bridge

Preparative thin layer chromatography has yielded the first-pure insertion products from acetylenes and butenolide dicobalt hexacarbonyls; the structure of one such product has been determined by X-ray crystallography and a related formulation is suggested for the other isomer formed in comparable amounts.     

Hexaorgano-substituted triatomics R3XYZR3: the configurations of organometallic sulphides (R3M)2S and the crystal and molecular structure of thio-bis[triphenyltin(IV)]

Crystals of thio-bis[triphenyltin(IV)], S(Ph₃Sn)₂, are orthorhombic, space-group P2₁2₁2₁, with a = 18.469(5), b = 17.648(5), c = 9.848(6) Å and Z = 4. The SnS distances are 2.405(9) and 2.417(7) Å and SnSSn angle is 107.3(2)°: there are no anomalous features in the structure analogous to those in O(Ph₃Sn)₂-MNDO calculations for a series of organometallic sulphides (Me₃M)₂S⁺ⁿ (M = Be, B, C, N, Si, P) indicate that the inversion barrier to linearity increases monotonically, and the skeletal bending force constant at linearity decreases correspondingly as the group Me₃M becomes more electro-negative.     

Metal complexes of mercaptoamines—I. Synthesis and crystal and molecular structure of tetrakis (3-amino-1-propanethiolato) trinickel(II)chloride

The reaction of nickel(II)chloride with γ-mercapto-propylamine in ethanolic solution gives the complex [Ni₃(MPA)₄]Cl₂(MPA=NH₂-(CH₂)₃-S). The complexes [Ni₃(MPA)₄]X₂(X=Br, I, ClO₄) can be synthesized from the chloride complex by addition of the sodium salt in aqueous solution. The crystal structure consists of discrete divalent trinuclear cations and chloride anions. Each sulphur atom of the ligand acts as a bridge between two nickel atoms, and the nitrogen atoms complete the coordination around the terminal nickel atoms. The geometry around the metal atoms is square-planar. The electronic and IR spectra of the complexes [Ni₃(MPA)₄]X₂(X=Br, I, ClO₄) indicate that all these compounds are composed of the [Ni₃(MPA)₄]²⁺ and X^? ions.     

The crystal and molecular structure of 9-methylphenanthro[4,3-a]dibenzothiophene

The crystal structure of 9-methylphenanthro[4,3-a]dibenzothiophene, C₂₅H₁₆S, M_r = 348.47, has been determined. Monoclinic, P2₁/c, a = 11.364(3), b, = 14.257(3), c = 11.575(2)Å, β = 116.26(2)°, V = 1681.9(7)ų, Z = 4, D_x = 1.38 g/cc, MoKα radiation λ = .71069 Å, F(000) = 728, T = 163K, R = .0458 for 2330 reflections. The structure compares favorably with that of hexahelicene and methylated derivatives. The thiophene moiety increases the helical core radius and decreases the pitch with respect to hexahelicene and its derivatives.