Alexander Z. Voskoboynikov

Synthesis and X-ray crystal structures of rac- and meso-2,2′-propylidene-bis(1-indenyl) zirconium dichlorides

Abstract An improved synthesis of 2,2′-bis(1-indenyl)propane and the corresponding ansa-complexes of zirconium are reported. Synthesis of a mixture of rac- and meso-2,2′-propylidene-bis(1-indenyl)zirconium dichlorides involves a treatment of ZrCl4 with bis[3-(trialkyltin)inden-1-yl]propane, where alkyl = ethyl, butyl, in toluene. This reaction gives the products in 92% yield and might be a convenient synthetic pathway to a number of straightforward ansa-metallocenes. Both rac- and meso-2,2′-propylidene-bis(1-indenyl)zirconium dichlorides were separated and isolated using simple work-up processes, and characterized by X-ray crystal structure analysis (rac:C2/c; a = 15.903(3) A, b = 11.105(2) A and c = 11.520(2) A; β = 121.61(3)°; Z = 4; V = 1732.6(5) A3; R = 0.0350; meso-: P1¯; a = 9.739(2) A, b = 12.798(4) A and c = 15.322(4) A; α = 101.18(2)°; β = 121.61(2)°; γ = 90.54(2)°, Z = 4; V = 1795.4(8) A3; R = 0.0417).

The reaction of alkyl derivatives of yttrium and lutetium with organic disulphides and diselenides: The molecular structure of {(tBuC5H4)2Y(μ-SePh)}2 · C6H6

The dimers {(tBuC5H4)2,Ln(μ-Me)}2 (LnY, or Lu) react with organic dichalcogenides R2E2 (ES or Se; RPh, nBu, tBu or CH2Ph) to form {(tBuC5H4)2Ln(μ-ER)}2 complexes with LnS or LnSe bonds. The molecular structure of {(tBuC5H4)2Ln(μ-SePh)}2·C6H6 has been determined by X-ray diffraction (P; a = 11.242(2) A, b = 11.388(2) A and c = 12.865(2) A; α = 110.32(2)°; β = 105.16(2)°; and γ = 102.84(2)°; Z = 1; dcalc. = 1.343 g cm−3; R = 0.0509 and Rω = 0.0532). The two yttrium atoms of the centrosymmetric dimeric molecule are bridged by two μ-SePh groups.

Synthesis and X-ray crystal structures of ansa-complexes of titanium, zirconium, and hafnium involving methylene-bis(indenyl) ligand

Abstract Synthesis of bis(indenyl)methane and the corresponding ansa-complexes of titanium(IV), zirconium(IV), and hafnium(IV) was performed. Mixtures of rac- and meso-methylene-bis(indenyl)zirconium and -hafnium dichlorides were obtained under a treatment of the respective metal tetrachlorides with bis[3-(tri-n-butyltin)indenyl]methane in toluene. The complexes, rac-H2C(indenyl)2MCl2, were isolated in 27% (M=Zr) and 31% (M=Hf) yields using a simple work-up process. These zirconium and hafnium complexes were characterized by X-ray crystal structure analysis. Methylene-bis(indenyl)titanium(IV) dichloride was prepared by two different pathways. The first one includes a treatment of TiCl4(THF)2 with dilithium salt of bis(indenyl)methane in THF. This procedure gives rac-H2C(indenyl)2TiCl2 in 16% only. An alternative reaction involving a treatment of TiCl4 with bis[3-(tri-n-butyltin)indenyl]methane results in rac-H2C(indenyl)2TiCl2 with 38% yield. A treatment of rac-H2C(indenyl)2TiCl2 with two equivalents of MeLi in diethyl ether gives rac-H2C(indenyl)2TiMe2, which has been isolated in 64% yield, and characterized by X-ray crystal structure analysis.

Metalcarbonylates of lanthanides. Unexpected formation of the trinuclear cluster [Na(DME)3]2[W3(CO)14]

Abstract The cluster [Na(DME)3]2[W3(CO)14] (I) has been isolated after the treatment of CpLuCl2 with an equimolar mixture of Na2W(CO)5 and Na2W2(CO)10 in dimethoxyethane (DME). The structure of I has been established by X-ray crystal analysis (Cmmm, a = 18.749(4), b = 15.074(3), c = 9.505(3) A, Z = 2, 653 reflections, R = 0.125). The cluster skeleton turned out to be a chain of three tungsten atoms with octahedral coordination. The WW distance is 2.79 A.

Insertion of tellurium(0) into yttrium—carbon bonds

Abstract The dimer {( t BuC 5 H 4 ) 2 Y(μ-Me)} 2 reacts with metallic tellurium to form {( t BuC 5 H 4 ) 2 Y(μ-TeMe)} 2 with a high yield.

Stoichiometric and catalytic activation of sp2 C−H bonds: molecular structure of Os3(μ-H)(μ3-nBuOC=CHPEt2)(CO)9 and catalytic properties of this and related Os and Ru clusters

Abstract The thermal reaction of nBuOCH=CHPEt2 with Os3(CO)12 gives a new osmium triangular cluster, Os3(μ-H)(μ3-nBuOC=CHPEt2)(CO)9 (1), which was isolated in 62% yield. The structure of 1 has been determined by X-ray diffraction ( P 1 ¯ , a = 12.914(3), b = 13.984(4), c = 16.375(4) A, α = 66.83(2), β = 77.82(2), γ = 77.97(2)°, Z = 4, dcalc = 2.552 g/cm3, R = 0.0399 for 6636 reflections). The μ3-nBuOC=CHPEt2 in 1 acts as a five-electron donor. It forms a σ-bond with one Os atom and coordinates the second and the third Os atoms of the cluster by its olefinic bond and the phosphorus atom, respectively. Both complex 1 and Os3(μ-H)(μ-CH=CHR)(CO)10 (R=nC6H13, Ph) catalyze the silylation of terminal olefins with Et3SiH to yield the corresponding trans-triethylvinylsilanes and alkanes in moderate yield even at ambient temperature. The proposed mechanism of olefin silylation catalyzed by triangular metal clusters involves the olefin C−H bond activation on the triangular cluster core and formation of an intermediate which has a structure similar to that of cluster 1.

Synthesis and molecular structures of the racemate and themeso-form of 2,2′-propylidene-bis(η5-indenyl)zirconium dichloride

A mixture ofrac- andmeso-2,2′-propylidene-bis(η5-indenyl)zirconium dichlorides was obtained in 95% yield. The compounds were separated, and their structures were established by X-ray structural analysis.

Titanium and zirconium complexes with η5: η1-4-(alkyl/arylamino)(dimethyl)silylindene ligands as catalysts for ethene polymerization

First members of a novel family of constrained geometry complexes of titanium and zirconium containing a short bridge between the amide and inden-4-yl fragments were obtained. When activated with methylaluminoxane, these complexes can be used as highly active catalysts for ethene polymerization producing high-molecular-weight polymers.

The cocrystal 10-(2-methyl-4-phenyl-1H-inden-6-yl)-10H-phenothia­zine–10-(2-methyl-7-phenyl-1H-inden-5-yl)-10H-phenothia­zine (0.54/0.46)

The title compound, 0.535C28H21NS.0.465C28H21NS, was synthesized by palladium-catalysed amination. The structure is composed of two isomeric molecules, viz. 10-(2-methyl-4-phenyl-1H-inden-6-yl)-10H-phenothiazine, and 10-(2-methyl-7-phenyl-1H-inden-5-yl)-10H-phenothiazine, in the refined ratio 0.535 (12):0.465 (12). The isomers differ by the localization of the double bond in the cyclopentadiene ring. There are two sites in the structure that are occupied by the isomers. The respective isomers are occupationally disordered in each site, the refined proportions being 0.640 (6):0.360 (6) and 0.43 (1):0.57 (1). Moreover, each isomeric molecule is chiral; due to the crystallographic centres of symmetry, the molecules are also present in enantiomeric pairs. The crystal structure is stabilized by weak π–π [C⋯C = 3.389 (2) Å] interactions.

Synthesis and molecular structure of Na{[1,3-(Me3Si)2C5H3]YbII}2(μ−I)

Abstract The reaction of Ybl2 with 2 equiv. of Cp″Na (Cp″-1.3-(Me3Si)2C5H3)in boiling toluene gives Na(Cp″2Yb} 2(μ-1) in 71% yield. On the evidence of X-ray diffraction analysis of this Yb(II) complex ( P 2 1 n , a = 13.5582(2), b = 17.4047(2), c = 26.9829(1) A , β = 97.562(1)°, Z = 4, d calcd = 1.404 g cm −1 , R = 0.0521 and w R 2 = 0.1107) the crystal unit cell contains crystallographically independent anion complex [Cp″2Yb-I-YbCp″2](Yb-I 3.1115(6), 3.0855(6) A) and Na+ cation. No additional neutral ligands were found at the metal atoms.