Preparation,properties and structure of stable ionic dialkylbis(2,2′-bipyridine)cobalt(III) tetraalkylaluminate and related complexes

Two types of dialkylcobalt(III) complexes containing the 2,2′-bipyridine ligand have been isolated as products of the reactions of tris(2,4-pentanedionato)cobalt(III) (Co(acac)₃), 2,2′-bipyridine (bpy), and alkylaluminums in diethyl ether. When high Al/Co ratios (Al/Co > 7) were used, ionic complexes, dialkylbis(2,2′-bipyridine)cobalt(III) tetraalkylaluminates, [CoR₂(bpy)₂][AlR₄] (R = CH₃, C₂H₅) were obtained exclusively. Similar reactions at lower ratios (Al/Co - 1.5–2.0) gave neutral CoR₂(acac)(bpy) (R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇). These compounds were characterized by IR and NMR spectroscopy as well as by elemental analysis and chemical reactions. Molecular structural analysis of the cationic dimethylcobalt compound confirmed the cis configuration. Stepwise formation of [CoR₂(bpy)₂][AlR₄] from Co(acac)₃ is postulated and the mechanism of the alkylation reaction is discussed.     

Systematische untersuchungen über das verhalten von organozinn-verbindungen gegenüber flüssigem schwefeldioxid : I. Reaktionen von tetraalkylstannanen mit flüssigem SO2

The SO₂ insertion into teraalkyltin compounds, R₄Sn (R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉), was investigated depending on the presence of water, reaction temperature and reaction time. According to eqns. (1)–(5), the reaction products R₃SnO₂SR, R₂Sn(O₂SR)₂, (R₃Sn)₂SO₄, R₂SnSO₄ and R₂SnSO₃ were isolated. Especially; at low temperatures (<0°) the following order of decreasing reactivity of the teraorganostannanes toward SO₂ is established: R = C₂H₅ > CH₃ > n-C₃H₇ > n-C₄H₉ > i-C₃H₇     

Reaktion von Alkyl- und Arylchlorsilanen mit Phosph(III) en-imidamiden

The reaction of RSiCl₃ (R=CH₃, C₂H₅, C₆H₅) and R₂SiCl₂ (R=CH₃) with one mole of the phosphenimidous amides R₂N–P=NR [R=R=Si(CH₃)₃; R=Si(CH₃)₃, R=C(CH₃)₃] yieds a four membered PN₂Si-ring system under elimination of (CH₃)₃SiCl.     

Reaktion von Alkyl- und Arylchlorsilanen mit Phosph(III) en-imidamiden

The reaction of RSiCl₃ (R=CH₃, C₂H₅, C₆H₅) and R₂SiCl₂ (R=CH₃) with one mole of the phosphenimidous amides R₂N–P=NR [R=R=Si(CH₃)₃; R=Si(CH₃)₃, R=C(CH₃)₃] yieds a four membered PN₂Si-ring system under elimination of (CH₃)₃SiCl.     

Darstellung neuer Alkylaminofluorsilane

Preparation of New Alkylaminofluorosilanes Aminofluorosilanes of the composition RSiF₂NR′R″ (R = H, CH₃, C₂H₃, C₆H₅; R′ = Si(CH₃)₃; R″ = C(CH₃)₃; R′ = R″ = i-C₃H₇), as well as C₆H₅SiF₂N[C(CH₃)₂CH₂]₂CH₂ are obtained by the reaction of fluorosilanes with the lithium salts of the corresponding amines in a molar ratio 1:1. The further reaction of these compounds with the lithium salts of alkylamines and anilin leads to the formation of the diaminofluorosilanes RSiFNR′R″NHR? (R? = C(CH₃)₃, i-C₃H₇, C₆H₅). The ¹H, ¹⁹F, ²⁹Si n.m.r. and mass spectra of the above mentioned compounds are reported.     

Kinetics and mechanism of acid hydrolysis of peroxyketals

The kinetics of hydrolysis of aliphatic ketone di-tert-butylperoxyketals R¹R²C=O, R¹, R²=CH₃, CH₃; CH₃, C₂H₅; CH₃, n-C₃H₇; CH₃, n-C₆H₁₃; CH₃, i-C₅H₁₀; CH₃, i-C₄H₉; C₂H₅, i-C₃H₇; n-C₄H₉, n-C₄H₉; CH₃, C₆H₅-CH₂, in dioxane in the presence of H₂SO₄ were investigated by IR spectroscopy. It was found that the reaction is reversible and takes place according to the equation R¹R²C· (OOC(CH₃)₃)₂ + H₂O;_H+ R¹R²C=O + 2HOOC(CH₃)₃. The proposed mechanism of hydrolysis includes the fast, quasiequilibrium formation of protonated peroxyketal and subsequent formation of the alkylperoxycarbenium ion. A three-parameter correlation equation is proposed for describing the initial rates of hydrolysis of R¹R²C(oo-t-Bu)₂ peroxyketals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2501–2506, November, 1990.     

Atranes. V. Proton magnetic resonance spectra of organyl and organoxysilatranes

The proton magnetic resonance spectra of eight organyl- and organoxysilatranes, (R = CH₃, C₂H₅, i-C₃H₇, CH₂=CH, C₆H₅, CH₃O, C₂H₅O, n-C₃H₇O) are investigated. The PMR resonance signals are interpreted, taking into account magnetic anisotropy of substituents and d-p interaction effects. The present communication gives results of proton magnetic resonance (PMR) studies of organyl- and organoxysilatranes (I). The table shows the compounds studied and the chemical shifts of the magneto-equivalent groups of protons in their spectra (see figure).For part IV see [1].     

DIORGANOTELLURBIS (ALKYLXANTHOGENATE), TEIL II

Abstract

Diphenyltelluriumbis(alkylxanthates) as well as telluracyclopentane-1,1-bis(alkylxanthates) of the general formula R₂Te(S₂COR')₂ and C_4H8Te(S₂COR′)₂ (R = C₆H₅ and R′ = CH₃, C₂H₅, i-C₃H₇) are obtained by reaction of diphenyltellurium-dichloride or telluracyclopentane-1,-diiodide with sodium-xanthates. The insertion of CS₂ into the corresponding organotelluriumbis-alkoxydes is only successful in the case of the cyclic compound. Diphenyltelluriumbis-alkoxydes react with decomposition. This decomposition in substance and in solution is investigated.

Man erhält Diphenyltellurbis(alkylxanthogenate), sowie Telluracyclopentan-1,1-bis(alkylxanthogenate) der Formel R₂Te(S₂COR′)₂ bzw. C₄H₈Te(S₂COR′)₂ mit R = C₆H₅, R′ = CH₃, C₂H₅, i-C₃H₇, durch Umsetzung von Diphenyltellurdichlorid bzw. Telluracyclopentan-1,1-diiodid mit den entsprechenden Natriumxanthogenaten. Prinzipiell führt auch die Einschiebung von CS₂ in Telluracyclopentan-1,1-bisalkoholate zu den entsprechenden Xanthogenatverbindungen. Bei der Umsetzung von CS₂ mit Diphenyltellurbis(alkoholaten) konnten nur die, für diese Xanthogenatverbindungen charakteristischen Zersetzungsprodukte isoliert werden. In diesem Zusammenhang wurde die thermische und solvensabhängige Zersetzung untersucht.     

Zur Reaktion von Fluorsilanen mit lithiierten Aminen

The reaction of fluorosilanes with lithium salts of bulky amines like tetramethyl-piperidine and di-tert. butylamine leads to stable aminofluorosilanes of the type R-SiF₂-NRR [R=F, C(CH₃)₃, C₆H₅, C₆H₄N(CH₃)₂]. Lithium salts of silylamines react analogously: R₂Si(NR-SiF₂R)₂ (R=R= =CH₃, R=C₆H₅). An eight membered Si–N-ring is obtained in the reaction of a disubstituted silylaminofluorosilane with the dilithium salt of a silylamine. The mass-,¹H-, and¹⁹F-NMR spectra of the above mentioned compounds are reported.     

Dimethyl-tellur-bis(alkylxanthogenate)

Tellurium-Dimethyl-bis(alkylxanthates) Tellurium dimethyl-bis(alkylxanthates) of the type R₂Te(S₂COR′)₂ with R = CH₃ and R′ = CH₃, C₂H₅, i-C₃H₇ are obtained by reaction of tellurium dimethyldiiodide with freshly prepared sodium xanthates. Another preparative method is the insertion of CS₂ in tellurium dimethylbis(alkoxydes). The X-ray analysis of (CH₃)₂Te(S₂COCH₃)₂ shows, that in the crystal the molecule has a ψ-pentagonal bipyramidal configuration around tellurium.     

Menthyl Substituted Phosphorus Compounds: Synthesis,Structures and NMR Studies

Abstract

Menthyl-substituted phosphorus compounds were synthesized:

(R=CH₃, C₂H₅, i-C₃H₇, t-C₄H₉, C₆H₅, L-Men, D-Men; Men=Menthyl) H-1- and C-13-NMR-spectra were treated by one- and two-dimensional methods to obtain stereospecific shift- and coupling-parameters. Problems of chiral, pseudo-chiral, pro-chiral and pseudo-pro-chiral compounds are discussed. Aromatic-ring-current-effects were calculated based on theories of Johnson/Bovey and Haigh/Mallion. Novel computer programs JOBO and HAMA were designed for convenient evaluation of ring-current-effects. The methods are demonstrated comparing Mosher's menthyl- und neo-menthylphosphineoxides L-Men(C₆H₅)(CH₃)PO and neo-Men(C₆H₅)(CH₃)PO R_(p) and S_(p) configurations. The programs may be obtained from the authors on request.     

Über die Reaktion von Schwefel mit Aminen und Formaldehyd. Eine neue Methode zur Herstellung von Thioformamiden und Dithiocarbamaten

The reaction of sulfur with primary or secondary amines and formaldehyde has been studied. A simple one step process for the preparation of thioformamides (RR′NCHS; R ? H, R′ ? CH₃, C₂H₅; R ? R′ ? CH₃, C₂H₅; R+R′ ? ? (CH₂), ? (CH₂), ? C₂H₄OC₂H) and the amine salts of N, N-dialkyl-dithiocarbamic acids (R₂NCS₂ · H₂NR₂, R ? CH₃, C₂H₅, C₄H₉; R₂ ? ? (CH₂), ? (CH₂), ? C₂H₄OC₂H) is reported. In addition, the isolation of diethylamidosulfoxylic acid, (C₂H₅)₂NSOH · 1/2 H₂O, the first derivative of a new class of compounds, is described. The physical properties and the ¹H-NMR. spectra of the above mentioned compounds are given.     

Diorgano-tellur-bis-(dialkylcarbamate) und -(dithiocarbamate)

Diorganyltellurium Bis-(dialkylcarbamates) and -(dithiocarbamates) Compounds of the type R₂Te(X₂CNR′₂)₂, with R ? C₆H₅, CH₃; R′ ? CH₃, C₂H₅, i-C₃H₇, c-C₆H₁₁, C₆H₅, and X ? S, are obtained by reaction of dimethyltellurium with tetraorganyl-thiuram-disulfides. Dimethyltellurium diiodide or diphenyltellurium dichloride react with sodium dithiocarbamates or with in situ prepared ammonium dithiocarbamates. Some compounds can be synthesized by reaction of diphenyltellurium oxide with amine in solutions of carbon disulfide. The synthesis of diphenyltellurium- and dimethyltellurium bis-(dimethylcarbamates) results from the interaction of diorganyltellurium diethanolate with dimethylammonium dimethylcarbamate. Decomposition reactions of the compounds in solid and solution are studied ¹H-NMR, ¹³C-NMR, and mass spectroscopically. Diorganyltellurium diethylen-bis-(N,N′-dimethyldithiocarbamates) are obtained by reaction of dimethyltellurium diiodide or diphenyltellurium dichloride and sodium ethylen-bis-(N,N′-dimethyldithiocarbamate) as polymeric products.     

A spin-trap ESR study of the regrouping of radicals with 1,3 or 1,5 hydrogen migration

Conclusions Spin-trap (2-methyl-2-nitrosopropane) ESR methods have been used to demonstrate the formation of R¹O₂CR²CH₂CH₂C₆H₁₃ (R¹=H, CH₃ and R²=Cl, CH₃) radicals during the photoinitiated reaction ( 2537 Å) of 1-octene with BrCHClCOOH and CH₃CHBrCOOCH₃ in the presence of tert-outyl peroxide and (C₃H₅)₃SiH. Formation of these radicals indicates regrouping of the R¹O₂CCHR²CH₂HC₆H₁₃ radical with 1,3 H atom migraion and, possibly, regrouping of the R¹O₂CCHR²CH₂CH(C₆H₁₃)CH₂CHC₆H₁₃ radical with 1,5 H atom migration.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 545–549, March, 1977.     

Differentiation of isomeric allylic alkenyl methyl ethers by Raman spectroscopy

The Raman spectra of several pairs of alkenyl methyl ethers of general structure R¹R²CCR⁵C(R³R⁴)OCH₃ and R¹R²C(OCH₃)C(R⁵)CR³R⁴ (R¹, R², R³, R⁴, R⁵ = H or C_nH_2n+1, n = 1-3) are reported and discussed, with a view to establishing whether Raman spectroscopy offers a viable means of distinguishing between these isomeric unsaturated species. Key bands associated with the ν(sp₂CH) and ν(CC) stretching modes are found to be particularly useful in this connection: R¹R²CCHCH₂OCH₃ and R¹R²C(OCH₃)CHCH₂ ethers (R¹, R² = CH₃, C₂H₅) are easily distinguished on this basis. Differentiation of their lower homologues, R¹CHCHCH₂OCH₃ and R¹CH(OCH₃)CHCH₂ (R¹ = CH₃, C₂H₅, C₃H₇), by similar means is also quite straightforward, even in cases where cis and trans isomers are possible. Pairs of isomeric ethers, such as CH₃CHC(CH₃)CH₂OCH₃ and CH₃CH(OCH₃)C(CH₃)CH₂, in which the structural differences are more subtle, may also be distinguished with care. Deductions based on bands ascribed to the stretching vibrations are usually confirmed by consideration of the signals associated with the corresponding δ(sp₂CH) deformation vibrations. Even C₂H₅CHCHCH(C₃H₇)OCH₃ and C₃H₇CHCHCH(C₂H₅)OCH₃ are found to have distinctive Raman spectra, but differentiation of these closely related isomers requires additional consideration of the low wavenumber region.     

Incorporation of Titanium(IV) into Sterically Hindered Schiff Bases of Heterocyclic β -Diketones Involving Ketooximes and Glycol as Coligands: Preparation and Structural Considerations

Titanium(IV) complexes of the general formula TiL(OPr ⁱ )₂ [where LH₂ = R CH₃ where R = ─C₆H₅, ─C₆H₄Cl(p)] were prepared by the interaction of titanium isopropoxide with sterically hindered Schiff bases derived from heterocyclic β -diketones in 1:1 molar ratio in dry benzene. The complexes TiL(OPr ⁱ )₂ were used as versatile precursors for the synthesis of other titanium(IV) complexes. Titanium(IV) complexes of the type TiLL'(OPr ⁱ ) (where L'H═R¹R²C═NOH, R¹ = R² = ─CH₃; R¹ = ─CH₃,R² = ─C₆H₅; R¹ = ─COC₆H₅, R² = ─C₆H₅) were synthesized by the reaction of TiL(OPr ⁱ )₂ with ketooximes (L'H) in equimolar ratio in dry benzene. Another type of titanium(IV) complexes having the general formula TiLGH(OPr ⁱ ) (where GH₂═HO─G─OH, G = ─CH₂─CH₂─) have been prepared by the reaction of TiL(OPr ⁱ )₂ with glycol in 1:1 molar ratio in dry benzene. Plausible structures of these new titanium(IV) complexes have been proposed on the basis of analytical data, molecular weight measurements, and spectral studies.     

Investigation of conjugation in the Si-O-C-C-N system by nuclear magnetic resonance

The proton-magnetic-resonance spectra were investigated for 19 -aminoethoxysilanes in the R_4-nSi(OCH₂CH₂NR₂)_n and R_3-m(CH₂CH₂OR)_m series, where R=CH₃, C₂H₅, or C₆H₅; R=H, CH₃, C₂H₅, or Si(CH₃)₃; and the values of n and m are 1–4 and 1–3, respectively. In the Si-O-C-C-N system the effect of substituents at the nitrogen or silicon atoms is transmitted either by conjugation in the chain or, when the conjugation is broken, by an induction mechanism.     

Effect of substituent nature on the equilibrium in the catalytic rearrangement of cyclosiloxanes in solution

Determinations are made of the polymer content of mixtures obtained by catalytic rearrangement of cyclosiloxanes with various substituents (CH₃, C₂H₅, n-C₃H₇, i-C₄H₉,C₆H₅, CF₃CH₂ CH₂, NCCH₂ CH₂ CH₂) at the silicon, in methylethyl ketone and acetone. It is found that the equilibrium cyclosiloxane-polycyclosiloxane is shifted to the left as volumes, and in particular polarities, of substituents increase. The causes of this are considered.     

用乙酰氯淬灭法测定Ziegler-Natta催化剂的活性中心数

The reactions of Solvay TiCl₃-AlR₃ (R=C₂H₅,i-C₄H₉) catalysts with acetyl chloride were studied. The main reaction, which is much faster than the reactions between A1R₃ and CH₃COC₁, is as follows:It is found that when CH₃COC₁ was introduced into 1-octene polymerization systems catalyzed by TiCl₃-AlR₃ for 5-15min, it reacted selectively and completely with the active centers to produce acetyl-ended polymer chains.With CH₃COC₁ as a quenching agent, the number of active centers in .these polymerization systems were determined by measuring the content of carbonyl in the polymer,and the results consist with those obtained by kinetics-molecular-weight method.     

Reactions of β-diketiminatoaluminum hydrides with tert-butyl hydrogenperoxide – Facile formation of dialuminoxanes containing Al–O–Al groups

Treatment of diphenyl-β-diketiminatoaluminum dihydride, LAlH₂ [1, L = {H₅C₆–NC(Me)}₂CH] with neopentyl- or trimethylsilylmethyllithium afforded the corresponding alkylderivatives LAlH(R) [R = CH₂–SiMe₃ (2), CH₂–CMe₃ (3)] by the precipitation of lithium hydride. Deprotonation of a methyl group instead of salt elimination occurred by the similar reaction of the more basic alkyllithium compound LiC(SiMe₃)₃. The reactions of the hydrides 1–3 with tert-butyl hydrogenperoxide did not yield the expected peroxo derivatives, instead the dialuminoxanes LAl(R)–O–Al(R)L [R = OCMe₃ (5), CH₂SiMe₃ (6), CH₂CMe₃ (7)] were isolated in high yields. Their Al–O–Al bridges deviated from linearity and had Al–O–Al bond angles of about 155° on average.