Reactions of salicylaldehyde with tris(pentaf luorophenyl)silanes and secondary amines

Reactions of tris(pentafluorophenyl)silanes RSi(C₆F₅)₃ with salicylaldehyde and secondary amines were studied. The reactions afforded α-pentafluorophenyl-substituted amines. Silanes RSi(C₆F₅)₃ (R = Me, Ph, C₆F₅, CH₂CH=CH₂, and CH=CH₂) were found to be efficient reagents for transfer of the C₆F₅ group to the iminium cation generated from salicylaldehyde and amine. However, tris(pentafluorophenyl)phenylethynyl-and tris(pentafluorophenyl)silanes were not able to serve as a source of a fluorinated substituent because of competitive transfer of acetylenide fragment or hydride. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 498–503, March, 2006.     

Synthesis and reactivity of trimethylsilyl substituted mono(cyclopentadienyl)titanium alkyl complexes

The preparation of a series of titanium half-sandwich compounds [Ti(η⁵-C₅H_5−x (SiMe₃) _x R₃] (x = 1–3, R = Cl, Me) and their reactivity for propene polymerization is reported. The compounds 1–3 polymerize propene, albeit in a much lower activity than the reported [Ti(η⁵-C₅Me₅Me₃]/B(C₆F₅)₃ catalyst. Unlike the reported [Ti(η⁵-C₅Me₅Me₃]/B(C₆F₅)₃ catalyst, the quasi living polymerization was not observed. Instead, we observe rather unusual temperature effects when the trityl salt [Ph₃C][B(C₆F₅)₄] was used as activator. The activity increases with increasing temperature, whereas when B(C₆F₅)₃ is used a decrease is observed The rather broad (>2) PDI indicates multisite catalysts, and ¹³C-NMR indicates predominantly atactic polypropene. The solid state structure of the hydrolysis product [{Ti(η⁵-C₅H₄(SiMe₃)Cl₂}O] (4) was determined.     

Synthesis of triple-decker iron and cobalt complexes with a central tetramethylphospholyl ligand

30-Electron triple-decker complexes [(η-C₅H₅)Fe(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ and [(η-C₄Me₄)Co(μ-η:η-C₄Me₄P)Fe(η-C₅Me₅)]PF₆ with a central tetramethylphospholyl ligand were synthesized by stacking reactions of cationic fragments [(η-C₅H₅)Fe]⁺ and [(η-C₄Me₄)Co]⁺ with nonamethylphosphaferrocene (η-C₄Me₄P)Fe(η-C₅Me₅). Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1647–1649, September, 2000.     

Synthesis of the first unsymmetrical 34-electron cationic cobalt-nickel triple-decker complex with a central cyclopentadienyl ligand [(η-C6Me6)Co(μ-η:η-C5H5)Ni(η-C5H5)]PF6

The first unsymmetrical 34-electron cationic cobalt-nickel triple-decker complex with a central cyclopentadienyl ligand [(η-C₆Me₆)Co(μ-η:η-C₅H₅)Ni(η-C₅)PF₆ was prepared by the reaction of [(η-C₆Me₆)₂Co]PF₆ with nickelocene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 798–799, April, 1999.     

1,2,3,4,7-Pentamethylindenyl complex [(η5-C9H2Me5)RhI2]2 as a synthon for the [(η5-C9H2Me5)Rh]2+ fragment

The reaction of the iodide complex [(η⁵-C₉H₂Me₅)RhI₂]₂ (1) or the acetonitrile complex [(η⁵-C₉H₂Me₅)Rh(MeCN)₃]²⁺ with Tl[Tl(η-7,8-C₂B₉H₁₁)] afforded rhodacarborane (η⁵-C₉H₂Me₅)Rh(7,8-C₂B₉H₁₁) (2). The cationic triple-decker complex with the bridging boratabenzene ligand [Cp*Fe(μ-η:η-C₅H₃Me₂BMe)Rh(η⁵-C₉H₂Me₅)]²⁺ (3) was synthesized by the reaction of the nitromethane solvate [(η⁵-C₉H₂Me₅)Rh(MeNO₂)₃]²⁺ with the sandwich compound Cp*Fe(η-C₅H₃Me₂BMe). The structure of 2 was established by X-ray diffraction. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1623–1625, August, 2008.     

30-Electron cationic iron- and cobalt-containing triple-decker complexes with a central cyclopentadienyl ligand. The first synthesis of the parent triple-decker iron complex with cyclopentadienyl ligands, [(η-C5H5)Fe(μ-η:η-C5H5)Fe(η-C5H5)]PF6

The parent 30-electron triple-decker iron complex with cyclopentadienyl ligands, [(η-C₅H₅)Fe(μ-η:η-C₅H₅)Fe(η-C₅H₅)]PF₆ (1), was prepared for the first time by visible-light irradiation of ferrocene and [(η-C₅H₅)Fe(η-C₆H₆)]PF₆ in CH₂Cl₂ at 0 °C. An analogous reaction performed with the use of (η-C₅H₅)Co(η-C₄Me₄) (2) instead of ferrocene afforded the thermally labile 30-electron cationic iron-cobalt triple-decker complex [(η-C₅H₅)Fe(μ-η:η-C₅H₅)Co(η-C₄Me₄)]PF₆. The latter reacted with compound 2 at 20 °C to form the symmetrical 30-electron cationic dicobalt triple-decker complex [(η-C₄Me₄)Co(μ-η:η-C₅H₅)Co(η-C₄Me₄)] PF₆. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya. No. 7, pp. 1364–1367, July, 1999.     

Synthesis of neutral and cationic monocyclopentadienyl alkyl niobium and tantalum complexes

Compound [NbCp′Me₄] (Cp′ = η⁵-C₅H₄SiMe₃, 1) reacted with several ROH compounds (R = tBu, SiiPr₃, 2,6-Me₂C₆H₃) to give the derivatives [NbCp′Me₃(OR)] (R = tBu 2a, SiiPr₃2b, 2,6-Me₂C₆H₃2c). The diaryloxo tantalum compound [TaCp^∗Me₂(OR)₂] (Cp^∗ = η⁵-C₅Me₅, R = 2,6-Me₂C₆H₃3) was obtained by reaction of [TaCp^∗Cl₂Me₂] with 2 equiv of LiOR (R = 2,6-Me₂C₆H₃). Abstraction of one methyl group from these neutral compounds 1-3 with the Lewis acids E(C₆F₅)₃ (E = B, Al) gave the ionic derivatives [NbCp′Me₂X][MeE(C₆F₅)₃] (X = Me 4-E. X = OR; R = SiiPr₃5b-E, 2,6-Me₂C₆H₃5c-E. E = B, Al) and [TaCp^∗Me(OR)₂][MeE(C₆F₅)₃] (R = 2,6-Me₂C₆H₃6-E; E = B, Al). Polymerization of MMA with the aryloxoniobium compound 2c and Al(C₆F₅)₃ gave syndiotactic PMMA in a low yield, whereas the tetramethylniobium compound 1 and the diaryloxotantalum derivative 3 were inactive.     

Synthesis of new cyclolinear permethyloligosilane-siloxanes

α,ω-Bis(heptamethylcyclotetrasiloxanyloxy)oligodimethylsilanes were synthesized for the first time by heterofunctional condensation of hydroxyheptamethylcyclotetrasiloxane with α,ω-dichloropermethyloligosilanes, Cl(Me₂Si) _n Cl (n=2, 4, or 6). The compounds obtained were characterized by spectroscopic methods. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 544–545, March, 1998.     

Triterpene glycosides fromTupidanthus calyptratus I. Structure of glycosides B1, B2, F1, and F2 from leaves of hooded tupidanthus

Chromatographically inseparable mixtures of oleanolic and ursolic 3-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranosides (glycosides B₁ and B₂) and their 28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl esters (glycosides F₁ and F₂) are isolated from the leaves ofTupidanthus calyptratus Hook f. (Araliaceae). The structures of the isolated glycosides are established from chemical methods and¹H and¹³C NMR spectra. Glycoside F₂ is a new triterpene glycoside. Simferopol' State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 627–633, September–October, 1999.     

Positional selectivity in electrophilic substitution reactions of π-excessive heterocycles (review)

Existing experimental data on positional selectivity in electrophilic substitution reactions of π-excessive heterocycles are classified. These data are discussed basing on the results of the authors' quantum-chemical calculations [RHF/6-31G(d), MP2/6-31G(d), and B3LYP/6-31G(d)] of the σ-complexes formed during attack of electrophiles such as H⁺, Me⁺, Me₃Si⁺, Br⁺, NO₂ ⁺, MeCO⁺, and SO₃ at the α- and β-positions of furan, thiophene, selenophene, pyrrole and its N-substituted derivatives, N-R-pyrroles (R = Me, t-Bu, SiMe₃, Si(i-Pr)₃, C₆H₄(p-NO₂), SO₂Ph, CHO, CO₂Me), and the corresponding α- and β-substituted electrophilic substitution products. The differences in energies of the α-and β-isomers of the σ-complexes characterize the preferred direction of electrophilic attack, while the differences in the energies of the isomeric products make it possible to assess the energy preference of one of them. Analysis of the obtained data demonstrates the effects of the studied heterocycles' structure, the nature of the electrophile, and the thermal and steric factors on the positional selectivity (α/β ratio) in electrophilic substitution reactions of π-excessive five-membered heteroaromatic compounds.     

Synthesis of α,ω-dihalopermethyloligosilanes and silane-siloxane copolymers

α,ω-Dibromopermethyloligosilanes, Br(SiMe₂) _n Br (n=2–4, 6), were prepared by the reaction of dodecamethylcyclohexasilane with bromine. The reaction of (Me₂Si)₆ with MCl₄ (M=Sn, Ti) proceeds with the cleavage of Si−Si- and Si−C-bonds with the formation of α,ω-dichloropermethyloligosilanes, Cl(SiMe₂) _n Cl (n=2–4, 6), and chloro derivatives of cyclohexasilane, Cl _m Si₆Me_12−m (m=1, 2). Silane-siloxane copolymers of regular structure were obtained by heterofunctional copolycondensation of α,ω-dihalopermethyloligosilanes with 1,5-dihydroxyhexamethyltrisiloxane. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1513–1517, August, 1997.     

Catenated Gallium Compounds Supported by a<Emphasis Type="Italic"> Tris</Emphasis>(pyrazolyl)hydroborato Ligand

[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with “GaI” to give a series of compounds that feature Ga–Ga bonds, namely [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaI₃, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGaI₂GaI₂( \textHpz^\textMe₂ {\text{Hpz}}^{{{\text{Me}}_{2} }} ) and [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga(GaI₂)₂Ga[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ], in addition to the cationic, mononuclear Ga(III) complex {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}⁺. Likewise, [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with (HGaCl₂) ₂ and Ga[GaCl₄] to give [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaCl₃, {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]₂Ga}[GaCl₄], and {[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGa[ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]}[GaCl₄]₂. The adduct [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ may be obtained via treatment of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]K with “GaI” followed by addition of B(C₆F₅)₃. Comparison of the deviation from planarity of the GaY₃ ligands in [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaY₃ (Y = Cl, I) and [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→GaY₃, as evaluated by the sum of the Y–Ga–Y bond angles, Σ(Y–Ga–Y), indicates that the [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga moiety is a marginally better donor than [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga. In contrast, the displacement from planarity for the B(C₆F₅)₃ ligand of [ \textTp^\textMe₂ {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C₆F₅)₃ is greater than that of [ \textTm^{\textBu\textt} {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→B(C₆F₅)₃, an observation that is interpreted in terms of interligand steric interactions in the former complex compressing the C–B–C bond angles.     

Neue Synthesen und Kristallstrukturen von Bis(fluorphenyl)quecksilber,Hg(Rf)2 (Rf = C6F5, 2, 3, 4, 6‐F4C6H, 2, 3, 5, 6‐F4C6H, 2, 4, 6‐F3C6H2, 2, 6‐F2C6H3)

New Syntheses and Crystal Structures of Bis(fluorophenyl) Mercury, Hg(R_f)₂ (R_f = C₆F₅, 2, 3, 4, 6‐F₄C₆H, 2, 3, 5, 6‐F₄C₆H, 2, 4, 6‐F₃C₆H₂, 2, 6‐F₂C₆H₃) Bis(fluorophenyl) mercury compounds, Hg(R_f)₂ (R_f = C₆F₅, C₆HF₄, C₆H₂F₃, C₆H₃F₂), are prepared in good yields by the reactions of HgF₂ with Me₃SiR_f. The crystal structures of Hg(2, 3, 4, 6‐F₄C₆H)₂ (monoclinic, P2₁/n), Hg(2, 3, 5, 6‐F₄C₆H)₂ (monoclinic, C2/m), Hg(2, 4, 6‐F₃C₆H₂)₂ (monoclinic, P2₁/c) and Hg(2, 6‐F₂C₆H₃)₂ (triclinic, P1) are described.     

Effect of substituents on the catalytic properties of bis(cyclopentadienyl)zirconium dichloride complexes with polymethylaluminoxane and AlBu1 3/CPh3B(C6F5)4 cocatalysts in ethylene polymerization

The catalytic properties of the complexes (RCp)₂ZrCl₂ (R=H, Me, Prⁱ, Buⁿ, Buⁱ, Me₃Si,cyclo-C₆H₁₁), and Me₂SiCp^*NBuⁱZrCl₂ (Cp^*=C₅(CH₃)₄) combined with the AlBuⁱ ₃−CPh₃B(C₆F₅)₄ cocatalyst in ethylene polymerization were studied. The specific activity of the substituted bis-cyclopentadienyl complexes decreases in the sequence: Me>Prⁱ>Buⁿ>Buⁱ>Me₃Si>cyclo-C₆H₁₁, which corresponds to the activity sequence for these complexes activated by polymethylaluminoxane (MAO) but is 4–20 times lower in absolute value. Comparison of the polyethylene samples obtained in the presence of the same complexes with MAO and AlBuⁱ ₃−CPh₃B(C₆F₅)₄ cocatalysts showed that polyethylene with much higher molecular mass, melting point, and crystallinity is formed in the presence of the ternary catalytic systems, and this indicates a different nature of the active sites of the catalytic systems. The effective activation energy of polymerization (≈3.6 kcal mol⁻¹), first order with respect to monomer and ≈0.4 order with respect to organoaluminum component, was found for the (PrⁱCo)₂ZrCl₂−AlBuⁱ ₃−CPh₃B(C₆F₅)₄ catalytic system. It was proposed on the basis of the kinetic data that AlⁱBu₃ enters into the composition of the active site to form a bridged heteronuclear cationic complex. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp 301–307, February, 2000.     

Mono‐ and Perfluoroaryliodine(III) Cyano Compounds – Synthesis,Reactivity, and Structure

C₆F₅I(CN)₂ and x‐FC₆H₄I(CN)₂ (x = 2, 3, 4) were isolated from reactions of the corresponding aryliodine difluorides ArIF₂ and a stoichiometric excess of Me₃SiCN in CCl₃F (0 °C) or CH₂Cl₂ (20 °C), respectively. In addition, x‐FC₆H₄I(CN)₂ compounds were synthesized in good yields on alternative routes, namely from 3‐ or 4‐FC₆H₄I(OC(O)CH₃)₂ or 4‐FC₆H₄I(OC(O)CF₃)₂ or from 4‐FC₆H₄IO and Me₃SiCN in CH₂Cl₂ at 20 °C. In the 1 : 1 reaction of C₆F₅IF₂ and Me₃SiCN a lower temperature was necessary to suppress partial disubstitution and to obtain the first example of a new type of aryliodine(III) cyanide compounds, C₆F₅I(CN)F. 4‐FC₆H₄I(CN)F could be isolated from the equimolar reaction of 4‐FC₆H₄IF₂ and Me₃SiCN in CH₂Cl₂ even at 20 °C. The new products were characterized by multi‐NMR and Raman spectroscopy. The molecular structures of C₆F₅I(CN)₂, 3‐ and 4‐FC₆H₄I(CN)₂, C₆F₅I(CN)F, and 4‐FC₆H₄I(CN)F are discussed and compared with that of C₆F₅IF₂. The reactivity of C₆F₅I(CN)F towards fluoride acceptors EF_n (BF₃, AsF₅) and R_xEX_?x (C₆F₅SiF₃, C₆H₅SiF₃, C₆H₅PF₄, Me₃SiCl, Me₃SiC₆F₅) were investigated and showed differing reaction patterns (fluoride abstraction, aryl transfer, chloride transfer). Besides the molecular entities C₆F₅I(CN)F and C₆F₅I(CN)Cl, the corresponding iodonium salts [C₆F₅(CN)I][BF₄] and [C₆F₅(CN)I][AsF₆] were isolated. The thermal stability of ArI(CN)₂ and ArI(CN)F, neat and in solution, as well as the reactivity of 4‐FC₆H₄I(CN)₂ towards the Lewis acid BF₃ are reported.     

Impact of Transition Metal Substituents on Polysilane Properties: Iron versus Ruthenium

Summary. The previously unknown ruthenio disilanes Rp–Si₂Me₄–C₆H₄X (Rp = η⁵-C₅H₅Ru(CO)₂; X = H, Br, –CHO, CH=C(CN)₂) were synthesized from ClSi₂Me₄C₆H₄X (X = H, Br) and Rp⁻ using conventional chemical methods. Trends in the UV/Vis absorption spectra indicate strong electronic coupling within the Rp–Si–Si–C_aryl fragment and, therefore, closely resemble the ones observed for the corresponding iron complexes. The four compounds however, were shown to be less sensitive towards UV irradiation. The crystal structure of Rp–Si₂Me₄–C₆H₄CH=C(CN)₂ was determined by X-ray diffraction and exhibits an all-trans-array of the Ru–Si–Si–C_aryl moiety, what is a basic requirement for optimal through-bond interaction.     

Synthesis and the fluxional behavior of the 30-electron cationic iron-molybdenum triple-decker complex with a central pentaphospholyl ligand, [(η-C7H7)Mo(μ-η:η-P5)Fe(η-C5Me5)]BF4

The reaction of [(η-C₇H₇)Mo(MeCN)₃)]BF₄ with (η-C₅Me₅)Fe(η-P₅) afforded the new 30-electron triple-decker complex [(η-C₇H₇)Mo(μ-η:η-P₅)Fe(η-C₅Me₅)]BF₄. Studies of the temperature dependence of the¹H NMR spectra demonstrated that the resulting compound contains a fluxional cyclohepatrienyl ligand. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1374–1376, July, 1999.     

Stabilities and Coordination Modes of α-Alaninephosphonic Acid in Copper(II) Heteroligand Complexes with Ethylenediamine, Diethylenetriamine or N,N,N′,N′,N″-Pentamethyldiethylene Triamine in Aqueous Solution

Solution equilibrium studies on Cu²⁺–L₁–L₂ ternary systems have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods (L₁ corresponds to polyamines such as ethylenediamine (en), diethylenetriamine (dien), or N,N,N′,N′,N″-pentamethyldiethylenetriamine (Me₅dien) and L₂ represents 1-aminoethylphosphonic acid (α-alaninephosphonic acid)). The obtained results suggest the formation of heteroligand complexes with [Cu(L₁)(α-Ala(P))] stoichiometry in all studied systems. Additionally, in the system with en the [Cu(en)(α-Ala(P))H₋₁]⁻ species is formed in basic solution. Our spectroscopic results indicate tetragonal geometry for the [Cu(en)(α-Ala(P))] species, geometry slightly deviated from square pyramidal for the [Cu(dien)(α-Ala(P))] complex and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me₅dien)(α-Ala(P))] species. The coordination modes in these heteroligand complexes are discussed.     

Mechanistic studies on cationic ring-opening polymerisation of cyclodextrin derivatives using various Lewis acids

In order to investigate the potential of cyclodextrins for the preparation of block-like substituted polysaccharides, we submitted mixtures of heptakis[2,3,6-tri-O-methyl]-β-cyclodextrin (Me₂₁-β-CD, 1) and heptakis[2,3,6-tri-O-methyl-d ₃]-β-cyclodextrin ((Me-d ₃)₂₁-β-CD, 2) to cationic ring-opening polymerisation (CROP). Reactions were performed with BF₃·OEt₂, methyl triflate (MeOTf), and Et₃OSbCl₆. Products were compared with respect to their degree of polymerisation (DP) and the average block length (BL). Highest DP was observed with BF₃·OEt₂, while Et₃OSbCl₆ was the most active initiator. Average block length decreased from 14 in the early stage of product formation to about 2 due to competing chain transfer reaction. ¹H NMR spectroscopy, GLC, GLC–MS, ESI-MS and MALDI-TOF-MS were applied for detailed investigations of side reactions. During incubation with BF₃·OEt₂, a stereroisomeric β-CD with one β-glucosidic linkage (Me₂₁-β-CD_6α1β, 3a (Me-d ₃)₂₁-β-CD_{6α 1β}, 3b) is formed as an intermediate, while linear Me₂₁- and (Me-d ₃)₂₁-maltoheptaose (4a/b) was detected in the early stage of the reaction promoted by MeOTf. In the case of Et₃OSbCl₆, both intermediates (3a/b, 4a/b) can be observed during the lag phase of polymerisation, but to a very low degree. End group analysis by GLC reveals that some alkyl exchange occurs at position 3 and 6 in the presence of Et₃OSbCl₆, and that polymerisation is also initiated by protons. Copolymerisation of heptakis[2,3,6-tri-O-benzyl]-β-cyclodextrin (Bn₂₁-β-CD, 5) and Me₂₁-β-CD (1) and subsequent debenzylation yielded a polymer of only 1,4-glcp-Me₃- and 1,4-glcp-residues. Reactivity of Bn₂₁-β-CD was significantly lower than of Me₂₁-β-CD, resulting in higher average block length of 1,4-glcp-Me₃-units.     

Synthesis and structures of tris(pentafluorophenyl)silylamines

Tris(pentafluorophenyl)silylamines were synthesized by silylation of amines and imines with (C₆F₅)₃SiCl or (C₆F₅)₃SiOTf in the presence of triethylamine. The crystal structures of the (C₆F₅)₃SiN(H)CH₂Ph and (C₆F₅)₃SiN(CH=CMe₂)CH₂Ph compounds were studied by X-ray diffraction. The crystal packings were analyzed by quantum chemical calculations in terms of the density functional theory (PBE exchange-correlation functional). Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1345–1352, July, 2007.