Metallocenes in oxidative-reductive transmetallzation with bis[tris(pentafluorophenyl)germyl]mercury

Conclusions The oxidative-reduction transmetallation reaction between bis[tris(pentafluorophenyl)-germyl]mercury and the dicyclopentadienyl derivatives of various metals can yield ionic multinuclear ate-type complexes, covalent compounds with a metal-metal bond, or ionic complexes that form by transfer of a cyclopentadienyl anion from the central metallocene atom to mercury.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2548–2555, November, 1986.The authors thank N. Walker and D. Stuart for providing the DIFABS program.     

Reactivity of thallium tris[tris(pentafluorophenyl)germyl] mercurate

Metallic lithium and dibenzenechromium displace thallium from (R^f₃Ge)₃HgTl·1.5DME (R^f = C₆F₅, DME = 1,2-dimethoxyethane) to give (R^f₃Ge)₃HgLi·3DME and [(R^f₃Ge)₄Hg][Cr(C₆H₆)₂]₂, respectively. Reactions of thallium germylmercurate with halides of metals and organometallics in DME/EtOH solution produce ionic compounds of [(R^f₃Ge)₃Hg]^? M⁺ type, which (depending on “M”) (a) may be isolated as pure compounds, (b) disproportionate, (c) form covalent derivatives R^f₃Ge-m or (d) undergo alcoholysis. A general scheme for the reactions has been proposed.     

Synthesis and thermal transformations of molecular complexes of bis[tris(trifluoromethyl)germyl]mercury(ii witho-quinones

Stable molecular complexes of bis[tris(trifluoromethyl)germyl]mercury(II) Hg[(CF₃)₃Ge]₂ (1) witho-quinones (3,6-di-tert-butylbenzoquinone-1,2 (2), 3,6-di-tert-butyl-4,5-dimethoxybenzoquinone-1,2 (3), and 1,4,5,7-tetra-tert-butyldibenzo[1,4]dioxin-2,3-dione (4)) have been synthesized and characterized by elemental analysis and IR and electronic absorption spectroscopies. Depending on the ratio between the starting reactants, the reactions ofo-quinones with1 gave complexes of the composition R₂Hg · Q (5,7,9) or R₂Hg · Q₂ (6,8,10), where Q=2 (5,6),3 (7,8),4 (9,10); R=Ge(CF₃)₃. According to the spectral data, the molecule ofo-quinone in R₂Hg · Q acts as a neutral ligand, whereas the second molecule ofo-quinone in R₂Hg · Q₂ is not coordinated to1. It has been found by ESR that thermolysis of polycrystalline samples of complexes6 and10 involves intermediate formation of radical pairs and finally yields paramagnetico-semiquinone complexes, SQGe(CF₃)₃, which are typical products of one-electron oxidation of Organometallic compounds byo-quinones.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1568–1573, August, 1995.The authors wish to thank M. A. Lopatin for his help in recording the electronic absorption spectra.This work was carried out with financial support from the Russian Foundation for Basic Research (Project No. 93-03-18369).     

Complexing reactions of bis[tri(pentafluorophenyl)germyl]cadmium

Conclusions Several complexes of bis[tri(pentafluorophenyl)germyl]eadmium with ligands of the donor type were synthesized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 702–703, March, 1973.     

Hydrogen bis[tris(4‐fluorophenyl)phosphane oxide] triiodide

In the title compound, C₃₆H₂₅F₆O₂P₂⁺·I₃⁻, hydrogen‐bonded [{(p‐FC₆H₄)₃PO}₂H]⁺ dimers assemble along the crystallographic c axis to form channels that house extended chains of triiodide anions. Although the I—I bond lengths of 2.9452 (14) and 2.9023 (15) Å are typical, the inter‐ion I...I distance of 3.5774 (10) Å is unusually short. A posteriori modelling of nonmerohedral twinning about (100) has been only partially successful, achieving a reduction in the maximum residual electron density from 5.28 to 3.24 e Å⁻³. The inclusion of two low‐occupancy I‐atom sites (total 1.7%), which can be interpreted as translational disorder of the triiodide anions along the channels, reduced the maximum residual electron density to 2.03 e Å⁻³. The minor fractional contribution volume of the nonmerohedral twin domains refined to 0.24 and simultaneous refinement of the inversion twin domains showed the crystal to be a 0.5:0.5 inversion twin.     

Un Nouveau diphosphene stable: Le bis[tris(trimethylsilyl)methyl] diphosphene

A new stable diphosphene (Me₃Si)₃CPPC(SiMe₃)₃ has been isolated and characterized particularly by its NMR data; the ³¹P NMR chemical shift appears to be the largest ever observed.     

Poly[tris(diorganophosphinato)alanes]

Poly[tris(diorganophosphinato)alanes], [Al(OPRR′O)₃]_n, were synthesized in which the organic moieties (R,R′) contained from one to eighteen carbon atoms. Polymeric properties depended upon the organic moieties; polymers were fusible, tractable, and flexible when the organic moieties contained six or more carbon atoms. Soluble polymers were prepared by using mixtures of symmetrical and unsymmetrical phosphinates. One polymer, poly{bis[n-butyl(benzyl)phosphinato]di-n-octylphosphinatoalane}, exhibited a degree of polymerization greater than 1000 and an exceptionally high intrinsic viscosity of 37 dl/g. The properties of the different polymers are discussed, and feasible structures are proposed.     

Metallierung von Triisopropylsilylarsan durch Bis(tetrahydrofuran)calcium‐bis[tris(trimethylsilylmethyl)zinkat]

Metalation of Triisopropylsilylarsane with Bis(tetrahydrofuran)calcium‐bis[tris(trimethylsilylmethyl)zincate] The transmetalation of bis(trimethylsilylmethyl)zinc with distilled calcium in THF yields bis(tetrahydrofuran)calcium bis[tris‐(trimethylsilylmethyl)zincate] ( 1 ). The trialkylzincate anion appears as a bidentate ligand with Ca‐C‐Zn three‐center‐bonds. The CaC bond lengths show values of 265.5(2) and 271.7(2) pm. The metalation of triisopropylsilylarsane gives tetrakis(tetrahydrofuran)calcium [1, 3‐bis(triisopropylsilylarsanyl)‐2, 4‐bis(triisopropylsilyl)‐1, 3‐dizinca‐2, 4‐diarsacyclobutane‐2, 4‐diide] ( 2 ). The central moiety is a sligthly distorted trigonal As₂CaZn₂ bipyramid with the arsenic atoms in apical positions. The mean Ca‐As bond lengths lie with a mean value of 291.4 pm in the charakteristic region for calcium bis‐(arsanides).     

Synthesis and properties of trefoil-shaped tris(hexadehydrotribenzo[12]annulene) and tris(tetradehydrotribenzo[12]annulene)

[reaction: see text] Trefoil-shaped tris(hexadehydrotribenzo[12]annulene) possessing a substructure of the ultimate two-dimensional C(sp)-C(sp(2)) network, graphyne, and the related tris(tetradehydrotribenzo[12]annulene) were synthesized, and their ground- and excited-state properties were investigated.     

Design and synthesis of tris[bis(benzylammonium)aryl]phosphines with bulky meta-substituents

A novel 3,5,3′,5′,3″,5″-hexakis(dimethylamino)methyl substituted triphenylphosphine analogue has been prepared. The six amine functionalities of the corresponding phosphine oxide and sulfide were alkylated quantitatively with methyl iodide and benzyl bromide, as well as with G1 and G2 Fréchet dendrons to afford the respective hexa-ammonium triarylphosphine oxides and sulfides. The phosphine sulfide derivatives were deprotected with P(n-Bu)₃ to afford a series of hexa-ammonium triarylphosphines that range from small molecules to first and second generation dendrimers (MW up to 5451.44). Upon formation of the hexa-ammonium salt a clear shift in ³¹P NMR is observed, indicative for opening of the C-P-C angle of the triaryl phosphine. Calculations on the hexacationic phosphines show an increased barrier of rotation around the P-C(aryl) bond with increasing size of the N-substituents. The calculated structure of the G2-dendron alkylated hexa-ammonium triarylphosphine shows that this dendritic phosphine has a disc-like rather than a cone-like structure, with an estimated cone angle of approximately 180°     

Bis[2,2′-ethylenedioxydibenzaldehyde bis(thiocarbohydrazide)] tris(pyridine) solvate

The title compound, a novel 30-membered 2:2 macrocyclic thio­carbohydrazone, C₃₄H₃₂N₈O₄S₂·3C₅H₅N, has been pre­pared and crystallographically characterized. The mol­ecule of the compound is twisted. One dioxa­butane group is boat-like in shape, whereas the other is highly disordered. The crystal structure is stabilized by inter- and intramolecular hydrogen bonds.