Vibrational spectra of cyclopropenes. II. IR spectra of 1,2-disubstituted cyclopropenes

The IR spectra were measured and the vibrational problem was solved for the 1,2-dimethyl-3-phenylcyclopropene (I) and 1,2-diphenylcyclopropene (II) molecules. The forms of the normal vibrations were determined, and the vibrations associated with vibrations of the exo- and endocyclic bonds of the ring were distinguished. It was shown that substitution at the double bond of cyclopropene leads to a change in the form of the symmetrical vibration of the ring in comparison with the vibration of unsubstituted cyclopropene. It was shown that a significant hypsochromic shift of the band of the symmetrical ring vibration in 1,2-disubstituted cyclopropenes in comparison with cyclopropenes that do not contain substituents at the C^1,2 atoms is due chiefly to the kinematic effect of the substituent. It was found that the introduction of substituents at the double bond of the ring leads to a decrease in the force constant of the double bonds.St. Petersberg University. Translated from Zhurnal Strukturnoi Khimii, Vol. 34, No. 1, pp. 125–132, January–February, 1993.     

Conversion of 2-amino-5-R-phenyl-1,3,4-oxadiazoles into 3-R-phenyl-5-alkoxy-1,2,4-triazoles

2-Amino-5-R-phenyl-1,3,4-oxadiazoles have been shown to isomerize in alcoholic potassium hydroxide solution to 3-R-phenyl-5-alkoxy-1,2,4-triazoles. The dissociative ionization of 3-R-phenyl-5-alkoxy-1,2,4-triazoles and 3-R-phenyl-1,2,4-triazolin-5-ones has been examined. The mass spectra of the oxadiazoles have been compared with those of the triazoles.Translated from Khimiya Geterotslklicheskikh Soedinenii, No. 11, pp. 1553–1556, November, 1986.     

Polymethine dyes — Indolo[3,2-d]thiazole derivatives

New polymethine dyes with an indolo[3,2-d]thiazole residue are described, and their spectral properties are discussed. Replacement of the vinylene group in the naphtho[1,2-d]thiazole residue by an NH group leads to a considerably greater bathochromic shift of the absorption maximum of carbo- and merocyanines as compared with replacement by a sulfur atom. The basicity of the indolo[3,2-d]thiazole residue is higher than the basicity of the naphtho[1,2-d]-thiazole and thionaphtheno[3,2-d]thiazole residues.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1606–1610, December, 1972.     

Methyl-substituted heterocyclic bases containing condensed selenonaphthene rings

The synthesis of 2-methylselenonaphtheno[2,3-d]thiazole and 2-methylselenonaphtheno[2,3-d]-oxazole is described.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 37–38, January, 1971.     

Crystal and molecular structure of 5-ethyl-5,10-dihydrido-10,10-diphenylphenazasiline

The structure of 5-ethyl-5,10-dihydro-10,10-diphenylphenazasiline has been determined from three-dimensional X-ray data collected by counter methods. The compound in the monoclinic space group P2₁/b with a 10.782(5), b 22.642(9), c 8.830(4) Å and γ 74°41′(2). The observed and calculated densities (Z = 4) are 1.22 and 1.21 g cm^-3, respectively. Anisotropic(Si, N, C)-isotropic block-diagonal least squares refinement gave a conventional R factor of 3.9% for 1871 reflections with I>2σ(I). The central six-membered ring of the tricyclic system adopts a boat conformation; the dihedral angle between the benzo-group planes is 157.3°. The CSiC angle in the heterocycle is 101.1(1)°; the mean SiC bond length is 1.850(2) Å (in the cycle) and 1.862(2) Å (with Ph group). The nitrogen atom is displaced 0.05 Å from the plane of the adjacent carbon atoms; the sum of the angle about N is 359.7°.     

Properties and analytical applications of the heteropolymolybdates of phosphorus, arsenic, silicon and germanium-IV Determination of phosphomolybdic and silicomolybdic acids via the molybdenum content, with phenylfluorone

Procedures are proposed for the determination of phosphorus and silicon in the ppM range, by extraction of phosphomolybdic and silicomolybdic acids with organic solvent, decomposition of the complex and spectrophotometric determination of its molybdenum content.     

Angular dependence of inductive effect and cis—trans influence in coordination compounds

Within the framework of the perturbation theory the implication of excited antibonding states in chemical bonding through the replacement of the AX bond by a more covalent AL bond in octahedra AX^″±₆ is shown to bring about greater weakening of the AX_tr bond in compounds of transition elements and of the AX_cis bond in compounds of non-transition elements. Weakening of AX_i bonds is proportional to non-diagonal matrix elements a_cis and a_tr between the respective localized orbitals. On the basis of these calculations the angular dependence of the inductive effect is also determined for compounds with multiple and donor—acceptor bonds. The predominant direction of the inductive effect in mutual influence of ligands depends on the nature of the atom A. The role of nonvalent interactions for determining the relative strength of bonds is considered. Theoretical conclusions are in agreement with the experimental data.     

Die IR-Spektren der Phasen ABTe3O8 (A = Fe,In, Sc; B = Nb,Ta) und UTe3O9

I.R. Spectra of the Phases A B Te₃O₈ (A = Fe, In, Sc; B = Nb, Ta) and UTe₃O₉ The infrared spectra of the title compounds have been recorded and discussed in comparison to formerly investigated M^IVTe₃O₈ phases. The spectrum of UTe₃O₉ (synthetic cliffordite) confirms the presence of uranyl groups and the structural relation of this compound to the fluorite.     

Synthesis and some properties of the diphenylmethyl and triphenylmethyl esters of uridine-3'phosphate

Summary The diphenylmethyl and triphenylmethyl esters of uridine-3'phosphate have been obtained and their stability under various conditions has been studied.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 1, pp. 48–51, 1966