Activation of the Ti(OC4H9)4-Al(C2H5)3 catalytic system in the selective dimerization of ethylene to 1-butene by the grignard reagent

The effect of an organomagnesium compound on the dimerization of ethylene to 1-butene was studied. The organomagnesium compound increases the catalytic activity of the Ti(OC₄H₉)₄-Al(C₂H₅)₃ system by 5–10 times. A high degree of selectivity (up to 99%) with respect to 1-butene was obtained. This makes it possible to eliminate a series of technological difficulties involved in the industrial production of 1-butene. The kinetics of the reduction of Ti(OC₄H₉)₄ by butylmagnesium chloride were studied by ESR and polarography.Chernogolovka Institute of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 10, pp. 2277–2283, October, 1992.     

Chlorido(η5‐cyclopentadienyl)bis(dimethylamido)titanium, [TiCl(η5‐C5H5)(NMe2)2]

The title complex, [Ti(C₅H₅)(C₂H₆N)₂Cl], exhibits two nearly planar dimethylamide groups oriented approximately perpendicular to each other. The Ti→cyclopentadienyl centroid vector lies nearly in the plane of one of the dimethylamide groups. Long‐range contacts between Ti—Cl and cyclopentadienyl H—C groups give rise to geometric ordering in the extended solid.     

Structure of ansa-dimethylsilyl-bis(η5-cyclopentadienyl)titana(IV) cyclohexasulfane,Ti[Me2Si(η5-C5H4)2]S5

The X-ray crystal structure of Ti[Me₂Si(η⁵-C₅H₄)₂]S₅ has been determined. The coordination about the titanium may be described as a distorted tetrahedron. The (centroid)? Ti? (centroid) angle is 129.2° and the S? Ti? S bond angle 96.1°. The cyclopentadienyl rings are linked by a dimethylsilyl bridge. The sixmembered ring TiS₅ has a cyclohexane-like chair configuration. The four S? S distances range from 2.048 to 2.059 Å. Important structural dimensions are compared to those of similar type compounds.     

1,1′-Disubstituierte Titanocen-dithiolen-Chelate des Typs (η5-Me3EC5H4)2Ti(S2C2R2) (E = C,Si, Ge)

1,1′-Disubstituted Titanocene Dithiolene Chelates of Type (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂R₂) (E = C, Si, Ge) Reaction of the titanocene dichlorides (η⁵-Me₃EC₅H₄)₂TiCl₂ (E = C, 1a ; E = Si, 1b ; E = Ge, 1c ) with the 1,2-dithiolates (NaS)₂C₂H₂, (NaS)₂C₂(CN)₂ or (LiS)₂C₆H₃Me-4 gave the new titanocene dithiolene chelates (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂H₂) ( 2a–c ), (η⁵-Me₃EC₅H₄)₂Ti[S₂C₂(CN)₂] ( 3a–c ) and (η⁵-Me₃EC₅H₄)₂Ti(S₂C₆H₃Me-4) ( 4a–c ). These have been characterized by ¹H NMR, IR, and mass spectroscopy, and have been compared with the unsubstituted η⁵-C₅H₅ analogues 2d, 3d and 4d . Activation energies for the chelate ring inversion in solution of 2a–c, 3a–d and 4a–c have been estimated by temperature-dependent ¹H NMR spectroscopy.     

Umsetzungen der Silylphosphine mit LiP(C2H5)2 und LiCH3

Whereas (CH₃)₃Si? P(C₂H₅)₂ does not react with LiP(C₂H₅)₂ (I), there are reactions of SiH-containing silylphosphines with one P(C₂H₅)₂ group as well as of SiH- and Simethylated silylphosphines with (I), yielding phosphorylated products and LiH according to equ. (1) (2). SiH-containing Silylphosphines, being Si? CH₃-free and having more than one P(C₂H₅)₂-group, such as HSi[P(C₂H₅)₂]₃, react with LiP(C₂H₅)₂ by exchange of Li for H, acc. to equ.(3). With (CH₃)₃SiCl, LiSi[P(C₂H₅)₂]₃ yields (CH₃)₃Si? Si[P(C₂H₅)₂]₃ and with SiH₃Br H₃Si? Si[P(C₂H₅)₂]₃. There is a cleavage of the Si? P bond with Li-CH₃ or n? LiC₄H₉. The reaction starts as shown in equ. (4), yielding (CH₃)₃SiH and (CH₃)₃Si? P(C₂H₅)₂ as intermediate products and finally (CH₃)₄Si (equ. 5).     

Photochemical reactions of (CO)2 (PPh3)MnC5H4Fe(CO)2C5H5 and (CO)2(PPh3)MnC5H4COFe(CO)2C5H5 with PPh3

Conclusions The photochemical reactions of (CO)₂(PPh₃)MnC₅H₄Fe(CO)₂C₅H₅ and (CO)₂(PPh₃)MnC₅H₄COFe(CO)₂C₅H₅ with PPh₃ gave the products of replacing the CO on the Fe atom by PPh₃: respectively (CO)₂(PPh₃)MnC₅H₄Fe (CO)(PPh₃)C₅H₅ and (CO)₂(PPh₃)MnC₅H₄COFe(CO)(PPh₃)C₅H₅.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2813–2815, December, 1977.     

Study of (π-C5H5)2Ti(CH3)Cl and (π-C5H5)2Ti(C6H5)Cl in soluble Ziegler catalysts

Soluble ethylene polymerization catalysts derived from (π-C₅H₅)₂Ti(R)Cl and R ′AlCl₂, where R = methyl or phenyl and R ′ = methyl or ethyl, were studied both by polymerization kinetics at 0°C and by diagnostic experiments. It was found that the first insertion of ethylene into the Ti? R bond is difficult when R = methyl or phenyl, and for this reason these catalysts show a different overall behavior than when R = ethyl or higher alkyl.     

Cyano Derivatives of Bis(cyclopentadienyl)titanium(IV). The crystal and molecular structure of μ-Oxo-bis[bis(cyclopentadienyl)cyanotitanium(IV)], [(η5-C5H5)2TiCN]2O

By the reaction of KCN with Cp₂TiCl₂ (Cp = η⁵-C₅H₅) in boiling methanol, bis(cyclopentadienyl)-methoxytitanium(IV) cyanide, Cp₂Ti(OCH₃)CN, is formed which in air is converted into the dinuclear oxygen-bridged derivative (Cp₂TiCN)₂O. By the same procedure, the bis(methylcyclopentadienyl) analogue [MeCp₂TiCN]₂O has been obtained. An X-ray diffraction study of (Cp₂TiCN)₂O has shown that the CN group acts as a unidentate ligand with a Ti? C bond length of 2.158 Å and a Ti? C? N bond angle of 177.7°, very close to linearity. The Ti? O bond distance, 1.836 Å, and the bond angle at the bridging O atom, 174.1°, are normal. The ligands are arranged in a nearly tetrahedral way around the Ti atoms. The structural results are compared to those for similar dinuclear titanium complexes.     

Mass spectrometry of metal compounds: II—mass spectrometric studies of [CF3EMn(CO)4]2, [CF3EFe(CO)3]2 (E = S,Se), CF3SeFe(CO)2C5H5 and CF3SCr(NO)2C5H5

The electron impact induced mass spectra of [CF₃SMn(CO)₄]₂, [CF₃SeMn(CO)₄]₂, [CF₃SFe(CO)₃]₂, [CF₃SeFe(CO)₃]₂, CF₃SeFe(CO)₂C₅H₅ and CF₃SCr(NO)₂C₅H₅ are reported. These compounds exhibit weak molecular ion peaks and undergo preferential loss of CO or NO groups. The CO or NO free fragments suffer typical loss of ECF₂(E = S, Se) with the simultaneous shift of F from carbon to metal. The ions [FFeC₅H₅]⁺ and [FCrC₅H₅]⁺ in the spectra of the cyclopentadienyl compounds prefer expulsion of π-cyclopentadienyls. The pyrolysis effects on the spectra of the compounds have been studied. An increase in temperature eases the expulsion of ECF₂ groups from all the compounds and favors the formation of [Fe(C₅H₅)₂]⁺ and [Cr(C₅H₅)₂]⁺ in the cyclopentadienyl compounds.     

Strukturchemie titan-organischer Verbindungen: Die Struktur von [(π-C5H5)2 Ti(NO3)]2O

Structural Chemistry of Organotitanium Compounds: Structure of [(π-C₅H₅)₂Ti(NO₃)]₂O Careful hydrolysis of (π-C₅H₅)₂Ti(NO₃)₂ in tetrahydrofuran yields crystals of [(π-C₅H₅)₂Ti(NO₃)]₂O ( A ). Crystal data of A : monoclinic, space group P2₁/c; lattice constants: a = 12.656(4), b = 10.181(5), c = 16.197(3) Å, ß = 93.57(3)º, Z = 4. As an X-ray analysis shows, the NO₃ groups act as monodentate ligands with Ti? O distances of 2.085 and 2.059 Å. The ligands are arranged in a nearly tetrahedral way around the Ti atoms. The bond angle at the bridging O atom is 171.8º.     

New rac‐XP(O)(OC6H5)(NHC6H4‐p‐CH3) [X = N(CH3)(cyclo‐C6H11) and NH(C3H5)] and rac‐(C6H5CH2NH)P(O)(OC6H5)(NH‐cyclo‐C6H11) mixed‐amide phosphinates

The mixed‐amide phosphinates, rac‐phenyl (N‐methylcyclohexylamido)(p‐tolylamido)phosphinate, C₂₀H₂₇N₂O₂P, (I), and rac‐phenyl (allylamido)(p‐tolylamido)phosphinate, C₁₆H₁₉N₂O₂P, (II), were synthesized from the racemic phosphorus–chlorine compound (R,S)‐(Cl)P(O)(OC₆H₅)(NHC₆H₄‐p‐CH₃). Furthermore, the phosphorus–chlorine compound ClP(O)(OC₆H₅)(NH‐cyclo‐C₆H₁₁) was synthesized for the first time and used for the synthesis of rac‐phenyl (benzylamido)(cyclohexylamido)phosphinate, C₁₉H₂₅N₂O₂P, (III). The strategies for the synthesis of racemic mixed‐amide phosphinates are discussed. The P atom in each compound is in a distorted tetrahedral (N¹)P(=O)(O)(N²) environment. In (I) and (II), the p‐tolylamido substituent makes a longer P—N bond than those involving the N‐methylcyclohexylamido and allylamido substituents. In (III), the differences between the P—N bond lengths involving the cyclohexylamido and benzylamido substituents are not significant. In all three structures, the phosphoryl O atom takes part with the N—H unit in hydrogen‐bonding interactions, viz. an N—H...O=P hydrogen bond for (I) and (N—H)(N—H)...O=P hydrogen bonds for (II) and (III), building linear arrangements along [001] for (I) and along [010] for (III), and a ladder arrangement along [100] for (II).     

Gehinderte Ligandenbewegungen in Übergangsmetallkomplexen : VII. Rotation der olefinliganden L = malein- und furmarsäuredimethylester in komplexen des typs C5H5Mn(CO)2L und C5H5Cr(CO)(NO)L

The restricted rotation of the olefin ligands L = dimethyl maleate and dimethyl fumarate in complexes of the type C₅H₅Mn(CO)₂L and C₅H₅Cr(CO)-(NO)L, respectively, has been investigated on the basis of their temperature-dependent ¹H NMR spectra. The olefinic ligand is arranged preferably in a position where the CC double bond is parallel to the plane of the cyclopentadienyl ring. The possible stereoisomers are discussed using this model. The ¹H NMR spectra of C₅H₅Cr(CO)(NO)(trans-CH₃OOCCHCHCOOCH₃) provide direct evidence that the configuration (R or S) at the metal is stable up to 120°C, and that the restricted motion of the olefin is exclusively rotation around the metal—olefin bond. The activation barriers of the olefin rotation are found to be appreciably lower in the C₅H₅Mn(CO)₂L complexes (ΔG^≠(T_C) 11–12 kcal mol^?1) than in the isoelectric C₅H₅Cr(CO)(NO)L compounds (ΔG^≠(T_C) 15–20 kcal mol^?1).     

Complexation of the 2, 4, 6‐Triallyloxy‐1, 3, 5‐triazine with Copper(I,II) Chlorides. Syntheses and Crystal Structures of [CuCl2·2C3N3(OC3H5)3], [Cu7Cl8·2C3N3(OC3H5)3], and [Cu8Cl8·2C3N3(OC3H5)3]·2C2H5OH

Interaction of copper(II) chloride with 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine leads to formation of copper(II) complex [CuCl₂·2C₃N₃(OC₃H₅)₃] ( I ). Electrochemical reduction of I produces the mixed‐valence Cu^{I, II} π, σ‐complex of [Cu₇Cl₈·2C₃N₃(OC₃H₅)₃] ( II ). Final reduction produces [Cu₈Cl₈·2C₃N₃(OC₃H₅)₃]·2C₂H₅OH copper(I) π‐complex ( III ). Low‐temperature X‐ray structure investigation of all three compounds has been performed: I : space group P1¯, a = 8.9565(6), b = 9.0114(6), c = 9.7291(7) Å, α = 64.873(7), β = 80.661(6), γ = 89.131(6)°, V = 700.2(2) ų, Z = 1, R = 0.0302 for 2893 reflections. II : space group P1¯, a = 11.698(2), b = 11.162(1), c = 8.106(1) Å, α = 93.635(9), β = 84.24(1), γ = 89.395(8)°, V = 962.0(5) ų, Z = 1, R = 0.0465 for 6111 reflections. III : space group P1¯, a = 8.7853(9), b = 10.3602(9), c = 12.851(1) Å, α = 99.351(8), β = 105.516(9), γ = 89.395(8), V = 1111.4(4) ų, Z = 1, R = 0.0454 for 4470 reflections. Structure of I contains isolated [CuCl₂·2C₃N₃(OC₃H₅)₃] units. The isolated fragment of I fulfils in the structure of II bridging function connecting two hexagonal prismatic‐like cores Cu₆Cl₆, whereas isolated Cu₆Cl₆(CuCl)₂ prismatic derivative appears in III . Coordination behaviour of the 2, 4, 6‐triallyloxy‐1, 3, 5‐triazine moiety is different in all the compounds. In I ligand moiety binds to the only copper(II) atom through the nitrogen atom of the triazine ring. In II ligand is coordinated to the Cu^II‐atom through the N atom and to two Cu^I ones through the two allylic groups. In III all allylic groups and nitrogen atom are coordinated by four metal centers. The presence of three allyl arms promotes an acting in II and III structures the bridging function of the ligand moiety. On the other hand, space separation of allyl groups enables a formation of large complicated inorganic clusters.     

Activation of biscyclopentadienyl hydride complexes of titanium and aluminum by NH- and OH-acids in the reactions of hydrogenation of olefins. Crystal and molecular structures of {(η5−Cp)2Ti(μ−H)2AlH]μ−N(C2H4)4O]}2 and [(η5−Cp)2Ti(μ−H(2AlH]2(μ−OC2H4OMe)[(μ1:μ5−C5H4)Ti(μ5−Cp)(μ−H)]2*

The reactions of Cp₂TiH₂AlH₂·Et₂O (1) with HN(C₂H₄)₂O, HOC₂H₄OMe, and water afforded the complexes {Cp₂TiH₂AlH[μ-N(C₂H₄)₂O]}₂ (5), [Cp₂TiH₂AlH(μ-OC₂H₄OMe)]₂ (6) and (Cp₂TiH₂AlH)₂O (4), respectively. Compounds 5 and 6 are dimers containing bridging Al?E₂?Al fragments (E=N or O). Complex 6 in solution converted to the hexanuclear compound [(η⁵?Cp)₂Ti(μ?H(₂AlH]₂(μ?OC₂H₄OMe)[(μ¹:μ⁵?C₅H₄)Ti(μ⁵?Cp)(μ?H)]₂ (8). The structures of complexes 5 and 8 were established by X-ray diffraction analysis. The rates of hydrogenation of hex-1-ene were determined using compounds 4–6 and the complexes [Cp₂TiH₂AlH(NEt₂)]₂ and [Cp₂TiH₂AlH(OEt)]₂ as catalysts. The probable mechanism of hydrogenation with the participation of bimetallic hydride complexes of aluminum and titanocene is discussed.     

Synthesis and comparative X-ray diffraction study of first ruthenocene-based pincer palladium complexes, PdCl[{2,5-(But 2PCH2)2C5H2}Ru(Cp′)] (Cp′ = C5H5 or C5Me5)

First ruthenocene-based palladium complexes PdCl[{2,5-(Bu^t ₂PCH₂)₂C₅H₂} Ru(Cp′)] (Cp′ = C₅H₅ (4) or C₅Me₅ (5)) were synthesized. Comparative single-crystal X-ray diffraction study of complexes 4 and 5 showed that the deviations of the cyclopentadienyl rings in these complexes from being parallel are 2.6 and 10.1°, respectively. In addition, the shift of the palladium atom relative to the plane of the metallated cyclopentadienyl ligand is 0.007 Å for 4 and 0.336 Å for 5. These differences in the structures of complexes 4 and 5 are due to close contacts between the pseudoequatorial tert-butyl groups at the phosphorus atoms and the unmetallated cyclopentadienyl ring. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1879–1884, November, 2006.     

Synthese und Molekülstruktur von [1,3-(Me3Si)2C5H3](Me3SiC5H4)ZrCl2

Synthesis and Molecular Structure of [1,3-(Me₃Si)₂C₅H₃](Me₃SiC₅H₄)ZrCl₂ . The unsymmetrically substituted zirconocene dichloride was prepared by reaction of trimethylsilylcyclopentadienyl lithium and 1,3-bis(trimethylsilyl)cyclopentadienyl lithium with ZrCl₄ · 2 THF. The molecular structure was determined (P2₁/a; a = 1 357.9, b = 1 900.0, c = 1 043.2 pm, β = 105,16°). The Zr? Cl distance are remarkably short.     

Protonation of the metal—metal bond in Fe2(μ-A)(μ-A′)(CO)4L2 complexes (A  A′ SC6H5, P(C6H5)2, P(CH3)2; A  SC6H5, A′ z.dbnd; P(C6H5)2; L z.dbnd; P(C6H5)3-n(CH3)n). : III. Experimental study of the influence of the A and A′ bridges on the basicity of the metal—metal bond

In order to check the influence of the bridges on the basicity of the metal—metal bond in Fe₂(μ-A)(μ-A′)(CO)₄L₂ complexes, the compounds with A  A′ SC₆H₅, P(C₆H₅)₂; P(CH₃)₂; A  SC₅H₅, A′ P(C₆H₅)₂ and L  P(CH₃)_3-n (C₆H₅)_n (n  0—3) have been prepared. IR and PMR spectroscopic results are interpreted in structural terms, and show that the Fe₂(SC₆H₅)(P(C₆H₅)₂.)-(CO)₄L₂ complexes are non rigid on the NMR time scale for n = 0, 1. Replacement of the first SC₆H₅ bridge by a P(C₆H₅)₂ bridge markedly increase the basicity of the metal—metal bond, but replacement of the second SC₆H₅ bridge has no significant effect.     

Basische Metalle. XIV. Synthese und Kristallstruktur von C5H5(PMe3)CoS5: Ein neuer Metallapentathia-Heterocyclus

Basic Metals. XIV. Synthesis and Crystal Structure of C₅H₅(PMe₃)CoS₅: A New Metallapentathia Heterocycle The dinuclear complex C₅H₅(PMe₃)Co(μ-CO)₂Mn(CO)C₅H₄Me ( 3 ) reacts with stoi-chiometric amounts of S₈ to form C₅H₅(PMe₃)CoS₅ ( 4 ) in practically quantitative yields. The cobalt-apentathia heterocycle 4 is also obtained by the reaction of C₅H₅(PMe₃)Co(h²-CS₂) ( 5 ) with S₈. Crystals of 4 are monoclinio with a = 8.467(3) Å, b = 12.128(4) Å, c = 14.210(4) Å and Å = 102.20(2)°. The chair form of the six-membered CoS₅ ring corresponds to that of the compounds (C₅H₅)₂TiS₅ and (C₅H₅)₂VS₅. In 4 , the cyclopentadienyl ligand occupies the axial and the trimethylphosphine group the equatorial position.     

Hydrolysis and chemical speciation of (C2H5)2Sn2+, (C2H5)3Sn+ and (C3H7)3Sn+ in aqueous media simulating the major composition of natural waters

The hydrolysis of (C₂H₅)₂Sn²⁺, (C₂H₅)₃Sn⁺ and (n‐C₃H₇)₃Sn⁺ has been studied, by potentiometric measurements ([H⁺]‐glass electrode), in NaNO₃, NaCl, NaCl/Na₂SO₄ mixtures and in a synthetic seawater (SSWE), as an ionic medium simulating the major composition of natural seawater, at different ionic strengths (0 ≤ I ≤ 5 mol dm^?3) and salinities (15 ≤ S ≤ 45), and at t = 25 °C. Five hydrolytic species for (C₂H₅)₂Sn²⁺, three for (C₂H₅)₃Sn⁺ and two for (C₃H₇)₃Sn⁺ are found. Interactions with the anion components of SSWE, considered as single‐salt seawater, are determined by means of a complex formation model. A predictive equation for the calculation of unknown hydrolysis constants of trialkyltin(IV) cations, such as tributyltin(IV), in NaNO₃, NaCl, and SSWE media at different ionic strengths is proposed. Equilibrium constants obtained are also used to determine the interaction parameters of Pitzer equations. Copyright © 2001 John Wiley & Sons, Ltd.