Heteroorganic derivatives of sulfur-containing heterocycles. 28. Calculation and interpretation of vibrational spectra of thienyl derivatives of group IVB elements

The frequencies and forms of the normal vibrations were calculated for trimethyl(2-thienyl)-substituted silane, germane, and stannane molecules. An interpretation of the results of an experimental study of the IR spectra and Raman spectra of compounds with the general formula R_nMMe_4–n (R=2-thienyl, M=Si, Ge, Sn, n=1...4) is given.See [1] for communication 27.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1467–1482, November, 1989.     

Heteroorganic furan derivatives. 61. Trimethyl(5-methyl-2-furyl)silane and trimethyl(5-methyl-2-furyl)germane

The transformations of trimethyl(5-methyl-2-furyl)silane and trimethyl(5-methyl-2-furyl)germane were studied upon vapor-phase oxidation by atmospheric oxygen on a V-Mo-Ag-O catalyst. Under these conditions, trimethyl(5-formyl-2-furyl)-silane and trimethyl(5-formyl-2-furyl)germane are formed albeit in only 5–7% yield. This low yield is a consequence of the thermal instability of the starting compounds and the aldehydes formed. The oxidation of 2-methyl-5-tert-butylfuran was studied under comparable conditions. The corresponding aldehyde was obtained in 30% yield. A scheme was proposed for the catalytic oxidation of 5-substituted 2-methylfurans.For Communication 60, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–24, January, 1987.     

Heteroorganic furan derivatives. 62. The molecular and crystal structure and reactivity of 2-furylhydrosilanes

In contrast to reported hydrosilanes with alkyl and aromatic substituents at the silicon atom, 2-furyl-, di(2-furyl)- and tri(2-furyl)silanes undergo dehydrocondensation with water, while di(2-furyl)silane also undergoes this reaction with ethanol in the absence of catalyst. The structures of 2-furyl-, di(2-furyl)- and tri(2-furyl)silane were studied by electron diffraction.For Communication 61, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 25–30, January, 1987.     

Research on furan acetal compounds

When 4-alkyl-2-(5-X-2-furyl)-1,3-dioxolanes are heated in the presence of tert-butyl peroxide the acetal ring is opened at the C-O 3–4 bond to give isomeric esters of 5-substituted furan-2-carboxylic acid. The structure of the product was confirmed by means of the UV and IR spectra, gas-liquid chromatography, and alternative synthesis.See [1] for communication VIII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1327–1329, October, 1976.     

Nitration of 2- and 4-[2-(2-furyl)vinyl]thiazole derivatives

Nitration of 4-methyl-2-[2-(nitro-2-furyl)vinyl]thiazole with a mixture of concentrated nitric and sulfuric acids leads to 4-methyl-5-nitro-2-[2-(3,5-dinitro-2-furyl)vinyl]thiazole. Under the same conditions 2-methyl- and 2-acetamido-4-[1-R-2-(5-nitro-2-furyl)vinyl]thiazoles (R=CH₃, Cl) are nitrated in the 3 position of the furan ring, 2-amino-4-[1-chloro-2-(5-nitro-2-furyl)vinyl]thiazole is nitrated in the 5 position of the thiazole ring and 2-acetamido-5-nitro-4-[2-(2-furyl)vinyl]thiazole undergoes profound changes. Under the influence of a mixture of of nitric acid and acetic anhydride the latter compound is converted quantitatively to the 5-nitro derivative (with respect to the furan ring), whereas 4-[2-(5-nitro-2-furyl)vinyl]thiazole derivatives do not undergo reaction.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 314–317, March, 1977.     

Mass spectra of derivatives of N-alkyl- and N-alkoxyalkylideneimine-2-carboxylic acids

The fragmentation of compounds of the RN(CH₂)_nCHCOX (n=1–5) and RNCH₂C(COX)₂ type, where X=OAlk and NH₂ and R=H, D, OAlk, and Cl, under electron impact was studied. When n=2–5, the chief fragmentation process is amine fragmentation, and the (M–COX)⁺ ion peak is the principal peak in the spectra at 30 and 12 eV. The fragmentation of three-membered heterocycles differs radically. The dominant fragmentation for 1-alkylaziridine-2-carboxylic and -2,2-dicarboxylic esters is splitting out of a radical from the ester group. This process is absent when R=H, D, C, and OAlk. Fragmentation with splitting out of the elements of alcohol for the esters and of ammonia for the amines is characteristic in the case of derivatives of 1-alkoxyaziridine-2-carboxylic and-2,2-dicarboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 624–633, May, 1977.     

Synthesis and Some Transformations of 2-(3-Amino-1-Phenylpropyl)furan

A preparative method was developed for the synthesis of ethyl furfurylidenecyanoacetate. Its condensation with phenylmagnesium bromide gave ethyl α-cyano-β-(2-furyl)hydrocinnamate, the decarboxylation of which led to β-(2-furyl)hydrocinnamonitrile. Reduction of this nitrile with lithium aluminum hydride gave 2-(3-amino-1-phenylpropyl)furan. Some of its transformations were studied.__________Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 517–521, April, 2005.     

Reactions of organylhalosilanes with 1,1,3,3-tetra- and hexamethyldisilazane

Organylchlorosilanes, and also SiCl₄, decompose 1,1,3,3-tetra- and hexamethyl-disilazanes with formation of hitherto unknown organylchlorosilazanes of general formulas R_4–nSiCl_n–1NHSiH(CH₃)₂ and R_4–nSiCl_n–1NHSi(CH₃)₃ (n=2–4) in yields of 54–98%. The IR and mass spectra of the prepared compounds were studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1159–1162, May, 1991.     

PMR of complexes of organohalostannanes with N-vinyl-N-ethylimidazole

The chemical shifts and spin-spin coupling constants of the protons of the vinyl and ethyl groups and of the imidazole ring in the PMR spectra of complexes R_4–n·SnX_n · mB, where R=C₂H₅, C₄H₉;X=Cl, Br, I; B is N-vinylimidazole or N-ethylimidazole; and n=1 (m=1) and 2 (m=2), are compared. The electronic and geometrical structures of these complexes are discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 391–394, March, 1973.     

Reaction of trimethyliodosilane with monosubstituted acetylene derivatives

Conclusions The reaction of phenylacetylene and 1-hexyne with Me₃SiI in the presence of Mg at 170–180° gave the corresponding trimethyl(organylethynyl)silanes in 80–95% yield.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, p. 897, April, 1981.     

Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

Electrochemical synthesis and magnetic studies of neutral transition metal imidazolates and pyrazolates

Summary The single-step electrochemical synthesis of neutral transition metal complexes of imidazole, pyrazole and their derivatives has been achieved at ambient temperature. The metal was oxidized in an Me₂CO solution of the diazole to yield complexes of the general formula: [M(Iz)₂] (where M = Co, Ni, Cu, Zn; Iz = imidazolate); [M(MeIz)₂] (where M = Co, Ni, Cu, Zn; MeIz = 4-methylimidazolate); [M(PrⁱIz)₂] (where M = Co, Ni, Cu, Zn; PrⁱIz = 2-isopropylimidazolate); [M(pyIz)_n] (where M = Co^III, Cu^II, Zn^II; pyIz = 2-(2-pyridyl)imidazolate); [M(Pz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; Pz = pyrazolate); [M(ClPz)_n] and [M(IPz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; ClPz = 4-chloropyrazolate; IPz = 4-iodopyrazolate); [M(Me₂Pz)_n] (where M = Co^II, Cu^I, Zn^II; Me₂Pz = 3,5-dimethylpyrazolate) and [M(BrMe₂Pz)_n] (where M = Co^II, Ni^II, Cu^I, Zn^II; BrMe₂Pz = 3,5-dimethyl-4-bromopyrazolate). Vibrational spectra verified the presence of the anionic diazole and electronic spectra confirmed the stereochemistry about the metal centre. Variable temperature (360-90 K) magnetic measurements of the cobalt and copper chelates revealed strong antiferromagnetic interaction between the metal ions in the lattice. Data for the copper complexes were fitted to a Heisenberg (S= ) model for an infinite one-dimensional linear chain, yielding best fit values of J=–62––65cm^–1 andg = 2.02–2.18. Data for the cobalt complexes were fitted to an Ising (S= ) model with J=–4.62––11.7cm^–1 andg = 2.06–2.49.     

Blue-shifted hydrogen-bonded complexes. II. CH3F(HF)1 n 3 and CH2F2(HF)1 n 3

The equilibrium structures, binding energies, and vibrational spectra of the clusters CH₃F(HF)_{1 n 3} and CH₂F₂(HF)_{1 n 3} have been investigated with the aid of large-scale ab initio calculations performed at the Møller–Plesset second-order level. In all complexes, a strong C–FH–F halogen–hydrogen bond is formed. For the cases n = 2 and n = 3, blue-shifting C–HF–H hydrogen bonds are formed additionally. Blue shifts are, however, encountered for all C–H stretching vibrations of the fluoromethanes in all complexes, whether they take part in a hydrogen bond or not, in particular also for n = 1. For the case n = 3, blue shifts of the ν(C–H) stretching vibrational modes larger than 50 cm⁻¹ are predicted. As with the previously treated case of CHF₃(HF)_{1 n 3} complexes (A. Karpfen, E. S. Kryachko, J. Phys. Chem. A 107 (2003) 9724), the typical blue-shifting properties are to a large degree determined by the presence of a strong C–FH–F halogen–hydrogen bond. Therefore, the term blue-shifted appears more appropriate for this class of complexes. Stretching the C–F bond of a fluoromethane by forming a halogen–hydrogen bond causes a shortening of all C–H bonds. The shortening of the C–H bonds is proportional to the stretching of the C–F bond.     

Research on furan acetal compounds

The possibility of the reduction of the furan ring to a tetrahydrofuran ring under the conditions of liquid-phase hydrogenation of 2-furyl-1,3-dioxanes on Raney nickel at atmospheric pressure is demonstrated. 2-Furyl or tetrahydro-2-furyl amino derivatives of 1,3-dioxane are formed in the case of 5-nitro-2-furyl-1,3-dioxanes as a function of the structure of the starting acetals. Data from the UV and IR spectra are presented.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1026–1029, August, 1977.     

Binuclear complexes with uranyl ions in non-equivalent coordination environments – 2. Synthesis and electrochemistry of the complexes with binucleating aroyl hydrazones and 1,10-phenanthroline

The ternary binuclear complexes, [(UO₂phen)₂L^1–5](NO₃) _n · S (1–3): n = 1; (4, 5): n = 2; S = solvent {H₃L^1–3 = 1-(2-hydroxybenzoyl)-2-(2-hydroxybenzal/2-hydroxy-3-methoxybenzal/2-hydroxynaphthal)hydrazine; H₂L^4,5 = 1-(2-aminobenzoyl)-2-(2-hydroxybenzal/2-hydroxy-3-methoxybenzal)hydrazine; phen = 1,10-phenanthroline} have been prepared and characterised, and their spectral and electrochemical properties studied. Complexes (4, 5) possess longer O=U=O bonds than those in complexes (1–3) as a result of the strong -donating phenolate group being replaced by an amino group. The i.r. spectra and electrochemical behaviour confirm the electronic non-equivalence of the coordination environments around the two uranyl ions in these complexes.     

Chlorine derivatives of octaorganylsilasesquioxanes

The chlorination of saturated and unsaturated octaorganylsilasesquioxanes proceeds through two pathways, leading to the formation of volatile and nonvolatile products, whose ratio depends on the reaction conditions. The volatile products of the chlorination of R-T₈ (R=C₂H₅ and CH=CH₂) are compounds with the general formula Cl_nR_8–n[SiO_1.5]₈, (n=1–7), obtained independently of the nature of the organic substituent and chlorinating agent. The nonvolatile chlorination products are silasesquioxanes, containing chlorine and chloroalkyl substituents on the atoms of the silicon-oxgyen core. Analysis of the vibrational spectral data indicated that the most significant changes in the molecular vibrational system are made by the halogenation of the silicon-oxygen core Si₈O₁₂.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 446–450, February, 1990.     

Heteroorganic derivatives of furan. 69. Analysis of electron structures of 2-furyltriethoxysilane and 1′-(2-furyl)-silatrane by the MO LCAO CNDO/2 method

The electron structures (charges on the atoms, additive populations of the atomic orbitals, and multiplicities of the chemical bonds) of 2-furyltriethoxysilane, 1-(2-furyl)silatrane, and the starting triethanolamine were analyzed by the MO LCAO CNDO/2 method taking into account the d orbitals. The localized molecular orbitals and the hybrid atomic orbitals that form them were constructed by the Polak projection method.see [1–3] for Communications 66–68.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1314–1321, October, 1989.     

The Complexes of Holmium with Methylenediphosphonate and 1-Hydroxyethylidenephosphonate

The composition and stability of holmium methylenediphosphonate (MDP) and 1-hydroxyethylidenephosphonate (HEDP) complexes were studied by potentiometric titration methods in 0.1M NaCl at 25 °C. It was found that besides L^4– anions the protonated H _n L^(4–n)– species (n = 1–3 for MDP and n = 1–4 for HEDP) are present in the pH region 3 to 10. The presence of the undissociated acids (H₄L) has not been unambiguously proved for MDP. The complexes of the composition HoH _n L (n varies from 1 to –2 for MDP and from 1 to –1 for HEDP) have been found if the concentration of the ligand is higher than the concentration of holmium. The protonation constants of both acids and the stability constants of the complexes discussed were determined and the comparison with literature data of analogical complexes of other lanthanides was performed.     

Tin(IV) and organotin(IV) derivatives of novel β-diketones: Part IV. Triorganotin(IV) complexes of fluorinated 4-acyl-5-pyrazolones. Crystal structure of (1-(4-trifluoromethylphenyl)-3-methyl-4-acetylpyrazolon-5-ato)triphenyltin(IV)

The synthesis of three 1-(4-trifluoromethylphenyl)-3-methyl-4-R¹(C=O)-5-pyrazolone proligands LH (L¹H; R¹=C₆H₅: L²H; R¹=CH₃: L³H; R¹=CF₃) and their interaction with R₃Sn(IV) acceptors (R=Me, Buⁿ, Ph) are reported. When R=Me or Buⁿ, aquo (4-acylpyrazolonate)SnR₃(H₂O) derivatives are obtained and the anionic donors 4-acylpyrazolonate (L⁻) act in the O–monodentate form. These triorganotin complexes are not stable in chlorohydrocarbon solvents and decompose to R₄Sn and bis(4-acyl-5-pyrazolonate)₂SnR₂. When R=Ph, stable (4-acyl-5-pyrazolonate)SnPh₃ derivatives, both in solution and in the solid state, are obtained. The crystal structure of (1-(4-trifluoromethylphenyl)-3-methyl-4-acetylpyrazolon-5-ato)triphenyltin(IV) shows a five-coordinate tin atom in a strongly distorted cis-bipyramidal trigonal environment (axial angle=161.2(2)°) with the acylpyrazolonate donor acting as an asymmetric O₂–bidentate species (Sn–O(1)=2.081(6) Å: Sn–O(2)=2.424(5) Å). Electronic effects are responsible for the different behavior shown by these trialkyl and triphenyl derivatives.     

Acceptor properties of titanium(IV) phenoxides

Summary Compounds of composition TiCl_4–n(OPh)_n · 2L (L = monodentate ligand, n = 1–4) have been prepared by the reaction of the parent titanium phenoxides (1 mol) with the ligand (2 mols) and characterized by elemental analysis, molar conductance, molecular weight and i.r. spectral studies.