Preparation and reactions of some sterically hindered silanols, including [tris(trimethylsilyl)methyl]silanetriol

The silanol TsiSiMe₂OH (Tsi = (Me₃Si)₃C) has been made by hydrolysis of the iodide TsiSiMe₂I in H₂O/dioxane or H₂O/Me₂SO. It has been shown to react with some acid chlorides RCOCl (R=Me, Et, CICH₂ Ph, 4-O₂NC₆H₄, and 3,5- (O₂N)₂C₆H₃) and anhydrides (RCO)₂O (R = Me, CF₃, or Ph) to give the carboxylates TsiSiMe₂OCOR, and with SO₂Cl₂ to give TsiSiMe₂OSO₂Cl. The triol TsiSi(OH)₃ has been made by treatment of TsiSiH(OH)I with H₂O/Me₂SO at 150°C or with a mixture of aqueous AgClO₄ and an organic solvent. The triol has been shown to react with RCOCl (R = Me, Et, or Ph) or (RCO)₂O (R = Ph) to give the corresponding TsiSi(OCOR)₃, with (CF₃CO)₂O to give TsiSi(OH)₂(OCOCF₃), and with a mixture of Me₃SiCl and AgClO₄ in benzene or one of Me₃Sil and (Me₃Si)NH to give TsiSi(OSiMe₃)₃. The triol is unusually stable, but decomposes at its m.p. of 285–290°C.     

Organopolysilane oligomers bearing transition-metal moieties: Synthesis, reactivities and molecular structure of [η-Me3SiMe2SiC5H4(CO)Fe(CO)2Fe(CO)-η-C5H4SiMe2SiME3]

Reaction of Me₃SiMe₂SiC₅H₅ (4), prepared from Me₃SiMe₂SiCl and C₅H₅Na, with Fe(CO)₅ in refluxing xylene afforded the title compound (3). The silicon-silicon bond in 3 is exceptionally stable in refluxing xylene and also in succeeding reactions to prepare a series of its derivatives. Thus, 3 reacted with I₂ in either chloroform or benzene, giving [η⁵-Me₃SiMe₂SiC₅H₄Fe(CO)₂I] (6). Compound 3 was reduced by sodium amalgam and reacted subsequently with CH₃I, PhCH₂Cl, CH₃COCl, PhCOCl, Cy₃SnCl (Cy = cyclohexyl) and Ph₃SnCl, producing [η⁵-Me₃SiMe₂SiC₅H₄Fe(CO)₂R][7 : R = CH₃ (a), PhCH₂ (b), CH₃CO (c), PhCO (d), Cy₃Sn (e) and Ph₃Sn (f), respectively]. The molecular structure of 3 has been determined by X-ray diffraction crystallography. It was found that 3 has a trans-configuration with a symmetrical centre located at the middle of the Fe---Fe bond. It is abnormal that the conformation of the disilane part around the Si---Si bond is almost eclipsed rather than staggered.     

Synthesis and chemistry of the bis(trimethylsilyl)amido bis-tetrahydrofuranates of the group 2 metals magnesium, calcium, strontium and barium. X-ray crystal structures of Mg[N(SiMe3)2]2·2THF and related Mn[N(SiMe3)2]2·2THF

Transamination reactions utilizing the compound mercuric bis(trimethylsilyl)amide, Hg{N(SiMe₃)₂}₂, in tetrahydrofuran (THF), and the metals Na, Mg, Ca, Sr, Ba and Al have been investigated. Thus the THF solvated compounds Na[N(SiMe₃)₂]·THF and M[N(SiMe₃)₂]₂·2THF, M = Mg, Ca, Sr and Ba (1–4), have been prepared. The X-ray crystal structures of 1 and the related manganese compound Mn[N(SiMe₃)₂]₂·2THF (5) are reported. Interaction of the silylamides, 2–4, with a range of crown ethers apparently proceeded with elimination of silylamine, (Me₃Si)₂NH, and novel ring opening of the crown ethers, generating species containing a donor alkoxide ligand with a vinyl ether function, presumably, ---O(CH₂CH₂O)_nCH=CH₂ (n = 3−5). The silylamides 2–4 were also cleanly converted to the corresponding alkoxides (from ¹H NMR data) in reactions with stoichiometric quantities of 3-ethyl-3-pentanol.     

Formation of a THF adduct of the organometallic samarium oxide [(C5Me5) 2Sm]2(μ-O)

(C₅Me₅)₂Sm(THF)₂ reacts with 1,2-epoxybutane in toluene to form, in addition to the toluene soluble [(C₅ Me₅)₂Sm]₂(μ-O), 1, the hexane soluble [(C₅Me₅)₂Sm(THF)]₂(μ-O), 2. In hexane, 2 loses THF to form 1 as a precipitate, but 1 cannot be converted to 2 by addition of THF at room temperature. Compound 1 does convert to 2 in low yield in THF at reflux. The reaction of (C₅Me₅)₂SM(phthalan) with 1,2-epoxybutane generates 1 and a phthalan analog of 2, [(C₅Me₅)₂Sm(phthalan)]₂(μ,-O), 3. Compound 2 reacts with Me₃CCN to form [(C₅Me₅)₂Sm(NCCMe₃)]₂(μ-O), 4, by displacement of THF.     

New heterometallic copper zinc alkoxides: synthesis, structure properties and pyrolysis to Cu/ZnO composites

The copper compound [(THF)KCu(O^tBu)₃]_∞ 1 was obtained by interaction of a 1:1 mixture of ZnCl₂/CuCl₂ with KO^tBu. Bi- and trifunctional aminoalcohols were used to synthesize the intramolecularly donor stabilized Cu(II) alkoxides Cu(OCH(R)CH₂NMe₂)₂ (3: R=Me, 4: =CH₂NMe₂) where 4 was structurally characterized. Lewis acid–base adduct formation with (Me₃Si)₃CZnCl gave the heterodinuclear compounds (Me₃Si)₃CZnCl · Cu(OCH(R)CH₂NMe₂)₂ (5: R=Me, 6: R=CH₂NMe₂), which were characterized by X-ray single-crystal structure analysis. The two metal centers Cu and Zn of 5 and 6 are bridged by two oxygen atoms to form a Cu–O–Zn core. Pyrolysis of compounds 5 and 6 in dry argon or a H₂/N₂ mixture at atmospheric pressure forms metallic copper and zinc oxide, whereas pyrolysis under O₂/Ar forms additionally oxidized copper species. Elemental analysis of the pyrolysis products showed carbon and nitrogen contamination. Scanning electron microscopy and energy dispersive X-ray analysis were performed to get information on the morphology and the chemical composition of the pyrolysis products.     

Zur reaktion von metall-koordiniertem kohlenmonoxid mit yliden : XX. “Ylidreaktionen” einfacher dicarbonyl(pentamethylcyclopentadienyl)rutheniumkomplexe

Treatment of the dimer complex [C₅Me₅ (CO)₂ Ru]₂ (1) with HBF₄ in CH₂Cl₂ at room temperature yields the hydrido-bridged dinuclear complex [(C₅Me₅)₂Ru₂(CO)₄H]BF₄ (2), and after refluxing in propionic anhydride [C₅Me₅(CO)₃Ru]BF₄ (5) is obtained, UV-irradiation of 1 in the presence of H₂CHal₂ (Hal = Cl, I) or trimethylphosphine leads to the formation of C₅Me₅(CO)₂Ru-Hal (3a, 3b) or C₅Me₅(CO)(Me₃P)RuH (4) respectively. Exchange reactions of 3a, 3b with LiAlH₄, NaOMe and Me₃ P give the complexes C₅Me₅(CO)₂RuX (6a,6b) (X=H, OMe), C₅Me₅(CO)(Me₃P)Ru-Hal (7a,7b) (Hal = Cl, I) and C₅Me₅(Me₃P)₂RuI (8). The interaction of 3b or 5 with Me₃P=CH₂ leads to the formation of the ylide complex [C₅Me₅(CO)(Me₃P)-RuCH₂PMe₃)Cl (9) or the rutheniumacyl-ylide C₅Me₅(CO)₂RuC(O)CH=PMe₃ (10). 4 reacts with Me₃P=CH₂ to give C₅Me₅(CO)(Me₃P)RuMe (11) and Me₃P via the intermediate formation of the phosphonium salt Me₄P[Ru(CO) (Me₃P)-C₅Me₅].     

Alkylaminophosphanyl substituted half-sandwich complexes of vanadium(III) and chromium(III): preparation and reactivity in ethylene polymerisation

[Cp^R(RPNEt₂)]M (Cp^R=t-BuC₅H₃, C₅(CH₃)₄, indenyl, fluorenyl; M=Li, K) smoothly react with VCl₃(Me₃P)₂ and CrCl₃(THF)₃ systems giving paramagnetic complexes [Cp^R(R¹PNEt₂)]MCl₂ (M=V(Me₃P)₂, Cr). After reaction with MAO these complexes are active in the polymerisation of ethylene yielding highly crystalline, high-density products of high molecular weight (M_w ranging from 100 000 to 4.5×10⁶ g mol⁻¹, 20≤T_p≤100 °C). Polymerisation with chromium complexes leads to the formation of polyethylenes with broad molecular weight distribution.     

ansa-Metallocene derivatives XXXIII. 2-Dimethylamino-substituted bis-indenyl zirconium dichloride complexes with and without a dimethylsilyl bridge: syntheses, crystal structures and properties in propene polymerization catalysis

Bis(2-N,N-dimethylamino-indenyl) zirconium dichloride, (2-(CH₃)₂N-C₉H₆)₂ZrCl₂, and dimethylsilyl-bridged bis(2-N,N-dimethylamino-indenyl) zirconium dichloride, (CH₃)₂Si(2-(CH₃)₂N-C₉H₅)₂ZrCl₂, were prepared by reaction of the corresponding ligand lithium salts with ZrCl₄ in toluene. Diffractometric structure determinations reveal C₂-symmetric complex geometries for both complexes. An increased electron density at the Zr center of the dimethylamino-substituted complexes is indicated by reduction potentials which are 0.3–0.4 V more negative than those of their unsubstituted analogs. When activated with methyl aluminoxane in toluene solution, (CH₃)₂Si(2-(CH₃)₂N-C₉H₅)₂ZrCl₂ catalyzes the polymerization of propene to polymers with a microstructure comparable with that of polymers produced with other Me₂Si-bridged bis(indenyl)ZrCl₂ complexes, but with a substantially increased fraction of i-propyl end groups derived from alkyl exchange between Zr-polymer and Al---Me species.     

Reactions of the sterically hindered organosilicon diol (Me3Si)2C(SiMe2OH)2 and some of its derivatives

The diol R₂C(SiMe₂OH)₂ (R = Me₃Si) has been shown to react with: SO₂Cl₂ to give R₂ Me₂; SOCl₂ to give R₂C(SiMe₂Cl)₂; Me₃SiI or Me₃SiCl to give R₂C(SiMe₂OSiMe₃)₂; R′COCl; (R′ = Me or CF₃) to give R₂C(SiMe₂O₂CR′)-(SiMe₂Cl); (R′CO)₂O (R′ = Me or CF₃ to give R₂C(SiMe₂O₂CR′)₂; with MeOH containing acid to give R₂C(SiMe₂OMe)₂; with neutral MeOH to give R₂C-(SiMe₂OMe)₂ and probably R₂ Me₂; MeLi to give R₂C(SiMe₂OLi)₂ (and the latter to react with PhMeSiF₂ to give R₂ Me₂). The diacetate R₂C(SiMe₂O₂CMe)₂ reacts with CsF in MeCN to give R₂C(SiMe₂F)₂; it does not react with NaN₃ or KSCN in MeCN, but the bis(trifluoroacetate) reacts with these salts with KOCN to give R₂C(SiMe₂X)₂ (X = N₃, NCS, NCO).     

Complexes of ruthenium(II) and -(III) with dimethylsulphoxide—III. Bis-iodo-tetrakis- dimethylsulphoxide ruthenium(II) and some other iodo complexes of ruthenium(II)

The ruthenium(II) complex [RuI₂(Me₂SO)₄] was synthesized and characterized. The Me₂SO ligands are all S-bonded. Reactions of RuI₂(Me₂SO)₄ with ligands containing P, N and S donor atoms have been carried out and the complexes obtained were characterized using different physical methods. [RuI₂L₄] (L= CH₃CN, Me₂SO and py), [RuI₂(CH₃CN)₂(PPh₃)₂] and [RuI₂(CS)(PPh₃)₃] have been synthesized using RuI₃ as the source material and characterized as above.     

Studies on organolanthanide complexes : LXIII. Synthesis, spectroscopic and X-ray crystallographic characterization of new early organolanthanide, organoyttrium hydride and organoholmium hydroxide complexes

Organolanthanide chloride complexes [(CH₃OCH₂CH₂C₅H₄)₂Ln(μ-Cl)]₂ (Ln = La, Pr, Ho and Y) react with excess NaH in THF at 45°C to give the dimeric hydride complexes [(CH₃OCH₂CH₂C₅H₄)₂Ln(μ-H)]₂, which have been characterized by IR, ¹H NMR, MS and XPS spectroscopy, elemental analyses and X-ray crystallography. [(CH₃OCH₂CH₂C₅H₄)₂Y(μ-H)]₂ crystallizes from THF/n-hexane at −30°C, in the triclinic space group P1 with a = 8.795(2) Å, b = 11.040(1) Å, c = 16.602(2) Å, = 93.73(1)°, β = 91.82(1)°, γ = 94.21(1)°, D_c = 1.393 gcm⁻³ for Z = 2 dimers. However, crystals of [(CH₃OCH₂CH₂C₅H₄)₂Ho(μ-OH)]₂ were obtained by recrystallization of holmium hydride in THF/n-hexane at −30°C, in the orthorhombic space group Pbca with a = 11.217(2) Å, b = 15.865(7) Å, c = 17.608(4) Å, D_c = 1.816 gcm⁻³ for Z = 4 dimers. In the complexes of yttrium and holmium, each Ln atom of the dimers is coordinated by two substituted cyclopentadienyl ligands, one oxygen atom and two hydrogen atoms (for the Y atom) or two hydroxyl groups (for the Ho atom) to form a distorted trigonal bipyramid if the C(η⁵)-bonded cyclopentadienyl is regarded as occupying a single polyhedral vertex.     

Anchimeric assistance in solvolysis of an organosilicon chloride and acetate

The compound (Me₃Si)₃CSiMeClI reacts with Hg(OAc)₂ in AcOH to give (Me₃Si)₂C(SiMe₂OAc)₂, under conditions in which the chloride (Me₃Si)₃CSiMe₂Cl is inert. Similarly, (Me₃Si)₂C(SiMe₂OAc)₂ reacts with CF₃CO₂H to give (Me₃Si)₂C[SiMe₂(O₂CCF₃)]₂ under conditions in which (Me₃Si)₃CSiMe₂OAc is inert. The results can be accounted for in terms of anchimeric assistance by the neighbouring acetoxy or trifluoroacetoxy group to the breaking of the Si---Cl or Si---OAc bond.     

碳锗双桥连二环戊二烯与羰基铁的反应

碳锗双桥连二环戊二烯(Me₂C)(Me₂Ge)(C₅H₄)₂(1)与五羰基铁在回流甲苯及二甲苯中的反应,得到正常的Fe-Fe键化合物(Me₂C)(Me₂Ge)[(η⁵-C₅H₃)Fe(CO)]₂(μ-CO)₂(3)和脱锗桥产物(Me₂C)[(η⁵-C₅H₄)Fe(CO)]₂(μ-CO)₂(4)以及一个结构新颖的化合物(Me₂C)[(η⁵-C₅H₃)[(Me₂Ge)Fe(CO)₂](η¹,η⁵-C₅H₃)[Fe(CO)₂](2).用X射线衍射分析測定了化合物3的晶体结构,并提出了可能的生成机理.     

Synthetic [FeFe]-H2ase models bearing phosphino thioether chelating ligands

Through the oxidation-reduction combination procedure, the neutral tri-substituted {2Fe3S} complex 2 was synthesized by replacing the CO ligand in 1 with phosphine. This substitution leads to the Fe-Fe bonds in 1 and 2 with large Lewis basicity difference, i.e. △pK_a^MeCN~10.     

四甲基双硅桥联环戊二烯基稀土金属有机配合物的合成及[Me4Si2(C5H4)2Sm(μ-Cl)(THF)]2的晶体结构研究

四甲基双硅桥联环戊二烯基钠与无水三氯化稀土在THF溶剂中反应合成了标题配合物Me₄Si₂(C₅H₄)₂LnCl[Ln:3Nd,4Sm,5Gd,6Y]和配合物Me₄Si₂(C₅H₄):Ln(C₅H₅)(THF)n[Ln:1La,n=1;2Pr,n=0].通过元素分析、¹HNMR、13CNMR和MS确证了配合物的结构,在THF溶液中重结晶获得配合物4的单晶,x射线衍射证明晶体结构为二聚体,4为单斜晶系,空间群为P2₁/c,晶体学数据a=1.2982(3)nm,b=1.2269(3)nm,c=1.3681(2)nm,β=96.79(2)°,V=2.162(1)nm³,Z=2,D_x=1.53g/cm³,偏差因子R=0.068.     

Über dimere dimethylmetall-bis(trimethylgermyl)amide des aluminiums, galliums und indiums

The dimethylmetal bis(trimethylgermyl)amides of Al, Ga, and In have been prepared from Li[N(GeMe₃)₂] and Me₂MCl (Me = CH₃, M = Al, Ga) or Me₂MCN (M = Ga, In) in inert solvents. The NMR (¹H, ¹³C) and vibrational spectra (IR and Raman) of these dimeric compounds have been assigned and discussed. According to the X-ray structure determination [Me₂InN(GeMe₃)₂]₂ crystallizes in the monoclinic space group C2/c (Z = 4, R = 0.032) and is isomorphous with the bis(trimethylsilyl) homologue.     

Anchimeric assistance by γ-substituents Z, Z=MeO, PhO, MeS or PhS, in reactions of the bromides (Me3Si)2(ZMe2Si)CSiMe2Br with AgBF4

The new organosilicon bromides (Me₃Si)₂(ZMe₂Si)CSiMe₂Br with Z=PhO or MeS have been prepared and new spectroscopic data obtained for the previously reported compounds with Z=H, F, Br, Me, Ph, MeO or PhS. Competitions between pairs of bromides for a deficiency of AgBF₄ in Et₂O, with the determination of the ratio of the fluoride products by ¹⁹F-NMR spectroscopy, have led to the following approximate relative reactivities of the bromides and so to the relative abilities of the γ-Z groups to provide anchimeric assistance to the leaving of Br⁻ in this reaction: Me, 1; Ph, 40; PhO, 3400; PhS, 5000; MeS, 7000; MeO, 54 000. In methanolysis in CH₂Cl₂, (Me₃Si)₂(MeOMe₂Si)CSiMe₂Cl has been found to be roughly 120 times as reactive as (Me₃Si)₂(PhOMe₂Si)CSiMe₂Cl. Combination of the results with previously available information suggests the following approximate order of ability of γ-groups Z to provide anchimeric assistance in reactions at the Si---X bonds in compounds (Me₃Si)₂(ZMe₂Si)CSiMe₂X: OCOMe>OMe>OCOCF₃>MeS>PhS, PhO>N₃, Cl>NCS>Ph>CH=CH₂>Me.     

Titanium imido complexes containing 1,3,5-triazacyclohexane ligands

The syntheses of the 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane-supported imido complexes [M(NR)(R′₃tach)Cl₂] (M = Ti or Zr (NMR only); R = Bu^t or 2,6-C₆H₃Prⁱ₂; R′ = Me or Bu^t) are reported, along with that of the thermally robust dibenzyl derivative [Ti(NBu^t)(Me₃tach)(CH₂Ph)₂]. The tert-butylimido ligand in [Ti(NBu^t)(Me₃tach)Cl₂] undergoes exchange with ArNH₂ (Ar = 4-C₆H₄Me or 2,6-C₆H₄Me or 2,6-C₆H₃Prⁱ₂) to form the corresponding arylimides [Ti(NAr)(Me₃tach)Cl₂]. The Me₃tach ring in [Ti(NR)(Me₃tach)Cl₂] undergoes slow exchange with Bu^t₃tach or Me₃tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) to give the ring-exchanged products [Ti(NR)(Bu^t₃tach)Cl₂] and [Ti(NR)(Me₃tacn)Cl₂], respectively. The complexes [Ti(NR)(Me₃tach)X₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂; X = Cl or CH₂Ph) exhibit room-temperature dynamic NMR behaviour via an unusual trigonal twist of the facially coordinated Me₃tach ligand, and the activation parameters for these processes have been measured and are discussed. The X-ray structures of [Ti(NR)(Bu^t₃tach)Cl₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂) and [Ti(NBu^t)(Me₃tach)(X)₂] [X= Cl or CH₂Ph) are reported. Me₃tach and Bu^t₃tach = 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane, respectively.     

Group 14 chalcogenides featuring a bicyclo[3.3.0]octane skeleton

Reactions of mixtures of Cl₂MeSiSiMeCl₂ (1) and Me₂MCl₂ (M=Si, Ge, Sn) with either H₂S/NEt₃ or Li₂E (E=Se, Te) yielded the bicyclo[3.3.0]octanes Me₂M(E)₂Si₂Me₂(E)₂MMe₂. A carbon containing analog, (CH₂)₅C(S)₂Si₂Me₂(S)₂C(CH₂)₅, was prepared from 1 and (CH₂)₅C(SH)₂. Crystal structures of three of these compounds were determined and the observed conformations of the bicyclo[3.3.0]octane skeletons compared with results of density functional theory calculations. Another class of silchalcogenides featuring a bicyclo[3.3.0]octane skeleton, E(Me₂Si)₂Si₂Me₂(SiMe₂)₂E, was formed from the doubly branched hexasilane (ClMe₂Si)₂Si₂Me₂(SiMe₂Cl)₂ and H₂S/NEt₃ or Li₂E. All products were characterized by multinuclear NMR (¹H, ¹³C, ²⁹Si, ⁷⁷Se, ¹¹⁹Sn, and ¹²⁵Te).     

双(2,4-二甲基戊二烯基)氯化钆的合成及晶体结构

合成双(2,4-二甲基戊二烯基)氯化钆{[2,4-(CH₃)₂C₅H₅]₂GD_cl}₂,并测定了晶体结构.晶体为单斜晶系,P2₁/n空间群.晶胞参数a=0.89141(18)nm,b=1.4486(3)nm,c=1.15925(15)nm,β=92.996(18)°,V=1.4949(4)nm³,Z=3.