Etude en luminescence UV—visible de la p-nitroaniline

The modification spectra of p-nitroaniline were evidenced by dipolar interaction effects and hydrogen bond complexes. This complexation was obtained either with the water traces present as impurity in aprotic solvents at low temperature, or by direct associations with OH groups in protic solvents. It conferred on the molecule a twisted conformation in the ground state due to the rotation of the NH₂ group around the CNH₂ bond. This important result agrees with an anomalous result obtained in emission data which shows dependence of fluorescence/phosphorescence intensity ratio (I_f/I_pn) on excitation energy. It is explained by mixed rotamers that exhibit this molecule in the ground state. The calculated geometry characteristics for this molecule show the ability of some theoretical methods to reproduce accurately the experimental data.     

Effet de la polarité du solvant sur les propriétés des états électroniques excités du 1,1′-binaphtyle: étude par spectroscopie UV-visible

A UV-vis emission spectroscopy study of the flexible molecule, 1,1′-binaphtyl as a function of solvent polarity allows one to obtain information on the excited singlet states. We show the existence of a charge transfer (CT) character state. This CT is evidenced by the solvent polarity effect, the measurement of polarization ratio and finally by comparison of the ratio intensities of phosphorescence and fluorescence.     

Etude de la fluorescence du 9,9′-bianthryl en solutions liquides et en milieux polymériques rigides à la température ambiante

The fluorescence of 9,9′-bianthryl (9,9′BA) is very sensitive to the polarity of the solvent. This molecule exibits an intramolecular charge transfer state in polar medium. The study of the fluorescence of 9,9′BA, in liquid solutions, shows a strong dependency of the Stokes shift versus the dipole moment m of the aprotic lowly viscous solvent. Moreover, this compound exhibits in polyvinylacohol (PVA) an original anomalous behaviour.     

1,1′,2,2′,6,6′-Hexaphenyl-4,4′-bipyridinium cation radical

Aniline reacts with 2,2,6,6-tetraphenyl-4,4-bipyrilium perchlorate to form 1,1,2,2,6,6-hexaphenyl-4,4-bipyridine perchlorate. A relatively stable cation radical is formed in the first stage of electrochemical reduction of this compound, which has been examined by ESR, where there are splittings from two nitrogen nuclei and the four protons in the 3,3,5,5 positions: a_N=0.38; a_H=0.14 mT.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, No. 1, pp. 61–64, January–February 1992.     

The crystal and molecular structures of 1,1′-divinyl-2,2′-biimidazolyl

The crystal and molecular structures of 1,1-divinyl-2,2-biimidazolyl (L) were determined by x-ray crystallographic analysis. It was established that the molecule of L has crystallographic symmetry 2 and a cisoid conformation with an angle of rotation of 128° between the imidazole rings. The length of the C²-C² bond is increased to 1.485(11) Å compared with the length of the analogous bond in unsubstituted 2,2-biimidazolyl (1.423 Å). Localization of the N=C multiple bond is observed [1.297(9) Å]. The other N-C bonds of the ring are almost equalized (1.374 Å) and are close to the standard values for bonds of the C _sp ²-N type in imidazoles. The angle between the plane of the heterocycle and the plane passing through the atoms of the vinyl group amounts to 7°.N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 117907 Moscow. Irkutsk Institute of Organic Chemistry, Siberian Branch, Russian Academy of Sciences, 664033 Irkutsk. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1376–1380, June, 1992.     

6,6′-Dibromo-3,3′-dimethoxy-2,2′-dihydroxy-1,1′-biphenyl: preparation and resolution

A pratical route to prepare the title biphenyl 1 starting from 3,3′,2,2′-tetramethoxy-1,1′-biphenyl 2 is described. Resolution of 1 was achieved by its conversion into the corresponding diastereomeric menthyldicarbonate. The absolute configuration of (P)-(+)-1 was confirmed by X-ray analysis of the related diastereomer.     

Crystal structure of 1,1′-biphenyl-2,2′,3,3′-tetracarboxylic and 1,1′-biphenyl-2,2′,3,3′,5,5′,6,6′-octacarboxylic acids: solid-state chiralization and dissociation

X-ray diffraction analysis revealed unexpected stereochemical features accompanying crystal self-assembly of the two title oligocarboxylic acids.     

5,5′-Diaryl-2,2′-biimidazole-1,1′-diols: Reactions with Methyl Iodide and Triphenylphosphine

Russian Journal of Organic Chemistry - The alkylation of 5,5′-diaryl-2,2′-biimidazole-1,1′-diols with an equimolar amount of methyl iodide gave the corresponding N-methyl...     

Synthesis of 1,1′-binaphthyl-2,2′-diamine from 2-naphthol under atmospheric pressure

A practical protocol to obtain 1,1'-binaphthyl-2,2'-diamine was developed from 2-naphthol and 2-naphthylhydrazine under mild conditions:solvent-free,125-130℃,atmospheric pressure.The convenient procedure makes the process amenable for large-scale synthesis of the versatile compound.     

Optically active 1,1′-di-tert-butyl-2,2′-dibenzophosphetenyl: a highly strained P-stereogenic diphosphine ligand

Both enantiomers of 1,1′-di-tert-butyl-2,2′-dibenzophosphetenyl were prepared from 2-bromobenzyl chloride and tert-butyldichlorophosphine. These ligands exhibited excellent enantioselectivity in the rhodium catalyzed asymmetric hydrogenation of methyl α-acetylamidocinnamate.     

2,2′-Dialkoxy, 2,2′-dihydroxy,and 2,2′-diamino derivatives of 1,1′-azobenzimidazole. The first synthesis of heterocyclic tetrazenes by means of a nucleophilic substitution reaction

2,2-Dimethanesulfonyl-1,1-azobenzimidazole is prepared by the oxidation of 1-amino-2-methanesulfonylbenzimidazole with lead tetraacetate. The reaction of this tetrazene with alkali in DMSO, with sodium alkoxides in the corresponding alcohol or ammonia, or with primary or secondary amines leads to the formation of 2,2-dihydroxy, 2,2-dialkoxy, or 2,2-diamino derivatives of 1,1-azobenzimidazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 190–193, February, 1992.     

Preparation,crystal structure and luminescence of lanthanide coordination polymers with 2,2′-dimethyl-4,4′-bipyridine-N,N′-dioxide

Four coordination polymers of the bidentate ligand 2,2′-dimethyl-4,4′-bipyridine-N,N′-dioxide (L), [La(L)(NO₃)₃(H₂O)] _n (1), {[Gd₂(L)₃(NO₃)₆]·6H₂O} _n (2), {[Sm(L)₂(H₂O)₄]·3ClO₄·2L·4H₂O} _n (3) and {[Nd(L)₂(H₂O)₄]·3ClO₄·2L·4H₂O} _n (4) have been synthesized by the diffusing solvent mixture method. Results of X-ray diffraction analysis reveal that 1, with a Ln/L stoichiometry of 1:1, displays a rare 3-D three-fold interpenetrating diamondoid framework, while 2 has a Ln/L stoichiometry of 1:1.5 and exhibits a polycatenane network with a {8²,10} topology and large channels accommodated by water. Complexes 3 and 4, with Ln/L stoichiometry of 1:2, have 3-D two-fold interpenetrating diamondoid structures and large voids. Nonlinear optical property of 2 and luminescence of 3 were also investigated.     

2,2′-二取代-1,1′-联萘化合物的NMR研究

用二维核磁共振谱（ＣＯＳＹ、ＨＭＱＣ、ＨＭＢＣ、ＦＧ＿ＨＭＢＣ）进一步研究了２，２′－二羟基－１，１′－联萘（１）、２，２′－二甲氧基－１，１′－联萘（２）、２，２′－亚甲二氧基－１，１′－联萘（３）、２，２′－亚乙二氧基－１，１′－联萘（４）、２－羟基－２′－甲氧基－１，１′－联萘（５）、２－羟基－２′－乙氧基－１，１′－联萘（６）、２－羟基－２′－异丙氧基－１，１′－联萘（７）、２－羟基－２′－丁氧基－１，１′－联萘（８）和２－羟基－２′－氧乙酸基－１，１′－联萘（９）等９个２，２′－二取代－１，１′－联萘化合物，确定了它们的氢谱和碳谱谱峰的归属，指出联萘化合物的立体结构、萘环的磁各向异性对质子谱有明显的影响，特别是Ｈ８（Ｈ８′）；而其对环碳的影响可以忽略。     

光学纯的cis,cis-2,2′-螺二氢茚-1,1′-二醇和2,2′-螺二氢茚-1,1′-二酮的合成

以丙二酸二乙酯和苄氯为起始原料,通过改进拆分方法,成功地合成了光学纯cis,cis-2,2′-螺二氢茚-1,1′-二醇(e.e.≥99%)和2,2′-螺二氢茚-1,1′-二酮(e.e.≥98%),收率较高。     

Crystal structure of three solvates of 1,1′-binaphthyl-2,2′-bicarboxylic acid with 2-picoline

From solutions in 2-picoline (2-methylpyridine), depending on the temperature of crystallization, the universal clathratogen — 1,1′-binaphthyl-2,2′-bicarboxylic acid (BBA) — precipitates as crystals of three types with different composition and structure. Under normal conditions (room temperature), the precipitate is crystals of BBA disolvate with 2-picoline; a temperature reduction of 20°C results in the crystallization of monosolvate dihydrate; and a temperature increase of the same level results in the precipitation of monosolvate. That is, as the temperature of crystallization rises, the number of included guest molecules gradually decreases and the space where they are located becomes more closed. In 1:1:2 BBA/2-picoline/H₂O solvate (space group P2₁/n, a = 11.991(2) Å, b = 9.317(2) Å, c = 22.283(5) Å, β = 99.77(3)○, V = 2453.3(9) ų, Z = 4), the carboxyl groups of the BBA molecule at the C21 atom are deprotonated and the released proton goes to the nitrogen atom of 2-picoline. BBA molecules interact with those of 2-picoline and water via H bonds to form infinite chains in direction [111], which, in their turn, join together into infinite two-dimensional sheets parallel to plane (?101). 2-Picoline molecules are located in the channels. In BBA/2-picoline disolvate (space group C ₂/c, a = 11.7523(11) Å, b = 13.8563(13) Å, c = 17.9615(13) Å, β = 108.044(9)○, V = 2781.1(4) ų, Z = 4), one BBA molecule and two H bond 2-picoline molecules form a 0-dimensional associate of the type G-H-G. The solvent molecules are also located in the channels. In BBA/2-picoline monosolvate (space group P2₁/c, a = 9.299(5) Å, b = 12.727(5) Å, c = 19.011(5) Å, β = 95.248(5)○, V = 2240.5(16) ų, Z = 4), each BBA molecule is H-bonded with a 2-picoline molecule to form a 0-dimensional associate of the type H-G. Guest molecules are located in closed cavities.     

Diastereoselective aminocarbonylation of a steroidal iodoalkene with 2,2′-diamino-1,1′-binaphthalene in palladium-catalysed reactions

A palladium-catalysed aminocarbonylation of a steroidal iodoalkene (17-iodo-5α-androst-16-ene) model compound with 2,2′-diamino-1,1′-binaphthalene as an N-nucleophile was carried out. The combination of a steroidal skeleton possessing central elements of chirality and a binaphthyl moiety with axial chirality was carried out resulting in a novel type of steroidal carboxamides. The binaphthalene—steroid conjugates are potential 5α-reductase inhibitors. Both epimers of the monocarboxamide and those of the dicarboxamide, formed with moderate diastereoselectivity, were isolated and fully characterised.