Synthesis and structure of 2,2′-diaminodiphenylditelluride bis-imines

Bis-imines of 2,2′-diaminodiphenylditelluride and 2-tosylamino (9a) and 2-hydroxybenzaldehyde (9b) were prepared and studied by X-ray diffraction, heteronuclear (¹H, ¹³C, ¹⁵N, and ¹²⁵Te) magnetic resonance, and quantum chemical calculations (Pbe1pbe/DGDZVP). According to the X-ray diffraction data, compound 9b in the crystal phase has nonsymmetrical structure: one of the tellurium atoms forms hypervalent bonding with the adjacent oxygen atom, while the second one is not involved in such interaction. The NMR study showed the symmetric molecular structure of imines 9a,b in DMSO-d₆ with the tellurium atoms interacting hypervalently with the C=N nitrogen atoms.     

Electrochemical and spectroscopic properties of poly-4,4′-dialkoxy-2,2′-bipyrroles

The structure and the electrochemical and spectral properties of two conductive electrochemically polymerized substituted bipyrroles 4,4′-methoxy-2,2′-bipyrrole and 4,4′-buthoxy-2,2′-bipyrrole were studied and compared. The polymers were characterized by cyclic voltammetry, FT-Raman spectroscopy, scanning electron microscopy, and in situ conductivity measurements at different pH and redox state.     

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.     

Preparation and Characterization of 2,2′-Dipicolyl Diselenide and Their Derivatives

Lithium 2-picolylselenolate/tellurolate is obtained by reacting lithiated 2-picoline with elemental selenium/tellurium which upon aerial oxidation gives 2,2'-dipicolyl diselenide in case of selenium while 1,2-bis(2-pyridyl)ethane in case of tellurium. Condensation of 2-picolylselenolate anion with a variety of electrophiles provides a facile synthesis of 2-picolylalkyl selenides in good to excellent yields. Quenching of lithiated 2-picoline with 2,2'-dipyridyl diselenide gives mixed 2-picolylseleno pyridine in low yield. All the compounds prepared are new and have been characterized by elemental analysis, 1 H NMR, 13 C NMR and mass spectral studies.     

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.     

Synthesis and properties of 2,2′-dipyridyl and 4,4′-dipyridyl complexes with thulium salts

Summary New complexes of 2,2-dipyridyl and 4,4-dipyridyl with thulium salts TmX ₃ (whereX=Cl^–, Br^–, NO ₃ ^– , NCS^–, and ClO ₄ ^– ) have been prepared and their solubilities in water at 21 °C were determined. The IR spectra of these compounds are discussed. The conditions of thermal decomposition of the complexes were also studied.

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Synthese und Eigenschaften von 2,2-Dipyridyl- und 4,4-Dipyridylkomplexen mit Thuliumsalzen

Zusammenfassung Es wurden neue 2,2-Dipyridyl- und 4,4-Dipyridyl-Komplexen mit Thuliumsalzen TmX ₃ (X=Cl^–, Br^– No ₃ ^– , NCS^–, ClO ₄ ^– ) dargestellt und ihre Wasserlöslihkeit bei 21 °C bestimmt. Die IR-Spektren werden diskutiert. Das thermische Verhalten der erhaltenen Komplexe wurde untersucht.

     

Experimental and theoretical investigations of absolute stereochemistry and chiroptical properties of enantiopure 2,2′-substituted 9,9′-bianthryls

The absolute stereochemistry of axially chiral 2,2′-X₂-9,9′-bianthryls (X=COOH, COOMe, and Cl) was determined by X-ray analysis of the (+)-quinidine salt of the diacid to be (M)-(−) or (P)-(+). The M isomers of these compounds showed specific rotations of −115, −123, and −32, respectively, in acetone. The circular dichroism (CD) as well as UV spectra of the two M isomers (X=COOMe and Cl) were investigated with the aid of theoretical calculations by the time-dependent DFT (TDDFT) method. The calculations reasonably reproduced the observed CD bands, and suggested a correlation between the signs of p or β′ bands and the absolute stereochemistry.     

Electrochemical alkylation of 2,2′-dipyridylamine

A method was developed for preparation of alkyl-(2,2-dipyridyl) amines, consisting of the reaction of alkyl halides with the N anion electrochemically generated from 2,2-dipyridylamine. The alkylation occurs regiospecifically, and CH₂Cl₂ can also be used as the methylating agent. Complexes of alkyl-(2,2-dipyridyl)-amines with Pd(2+) and Cu(2+) salts were obtained.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 155–159. January, 1991.     

Synthesis of Polyiodides of N- and S-S-Acetonyl Derivatives of 2,2′-(Disulfanediyl)- and 2,2′-[Alkanediylbis(sulfanyl)]-bisbenzimidazolium

Russian Journal of Organic Chemistry - 2,2′-(Disulfanediyl)- and 2,2′-[alkanediylbis(sulfanyl)]-bisbenzimidazoles react with aliphatic, aromatic, and heterocyclic α-iodoketones in...     

Spectroscopic and electrochemical properties of cyclopalladated complexes of 2,3-diphenylquinoxaline and 2,2′,3,3′-tetraphenyl-6,6′-biquinoline

Comparative study of cyclopalladated ethylenediamine complexes of 2,3-diphenylquinoxaline (Hdphqx) [Pd(dphqx)En]ClO₄ and 2,2′,3,3′-tetraphenylbiquinoline (H₂tphbq) [(PdEn)₂(μ-tphbq)](ClO₄)₂, and the free heterocyclic ligands was performed by means of ¹H NMR spectroscopy, electronic absorption and emission spectroscopy, and cyclic voltammetry. It was shown that cyclopalladation gives rise to a long-wave absorption band in the visible spectrum, a batochromic shift of the vibrationally structured phosphorescence band, and an anodic shift of the ligand-centered reduction potential of the complexes com-pared to free ligands.     

Improved Synthesis of 4,4′-Disubstituted-2,2′-Bipyridines

Ruthenium(II) tris(2,2′-bipyridine) complexes show interesting photochemical properties^1. Complexes containing substituents in the 4-and 4′-position of the 2,2′-bipyridine ligand have recently been used in systems which are aimed at the conversion and storage of solar energy^2,3. 2,2′-Bipyridine has a long history as a metal-chelating agent⁴. The use of 4,4′-disubstituted bipyridines as metal-chelating agents so far has been restricted probably because the reported syntheses of these compounds are rather laborious and the yields are low or moderate^5–8.     

Cotton-mouton constants and spatial structure of 2,2′- and 4,4′-dipyridyls and their salts in solutions

Magnetic birefringence has been used in studying the spatial structure of a series of dipyridyl derivatives in hydrochloric acid solutions, and also some of their quaternary salts in water. It has been shown that when the change is made from the molecular forms of the 2,2- and 4,4-dipyridyls to their protonated mono and bis derivatives, the angles of rotation of the aromatic rings are very little changed; in the methylated cation, the degree of acoplanarity increases.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2771–2775, December, 1991.     

Thermochemistry of 2,2′-dipyridil N-oxide and 2,2′-dipyridil N,N′-dioxide. The dissociation enthalpies of the N−O bonds

In this paper, the first, second and mean (N?O) bond dissociation enthalpies (BDEs) were derived from the standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, ${\mathrm{\Delta }}_{\text{f}}{H}_{\text{m}}^{°}(\text{g})$, at T = 298.15 K, of 2,2′-dipyridil N-oxide and 2,2′-dipyridil N,N′-dioxide. These values were calculated from experimental thermodynamic parameters, namely from the standard (p° = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, ${\mathrm{\Delta }}_{\text{f}}{H}_{\text{m}}^{°}(\text{cr})$, at T = 298.15 K, obtained from the standard molar enthalpies of combustion, ${\mathrm{\Delta }}_{\text{c}}{H}_{\text{m}}^{°}$, measured by static bomb combustion calorimetry, and from the standard molar enthalpies of sublimation, at T = 298.15 K, determined from Knudsen mass-loss effusion method.     

Coordination behaviour of 2,2′-bipyridine towards the dichloroacetates of zinc and cadmium

The coordiantion compounds [Zn(C₁₀H₈N₂)(Cl₂HCCOO)(H₂O)₃]⁻·[Zn(C₁₀H₈N₂)(Cl₂HCCOO)₃]⁺ and [Cd(C₁₀H₈N₂)₂(Cl₂CHCOO)₂] were synthesised and characterised by elemental and thermal analysis, IR and UV–VIS spectroscopy, and X-ray crystallography. The complexes are air stable and well-soluble in water. The zinc atoms are five and six coordinated and the cadmium atom is six coordinated. The coordination polyhedra of central atoms can be described as trapezoidal pyramid and octahedron in zinc compound and as rectangular bipyramid strongly distorted towards skew trapezoidal bipyramid in cadmium compound. In both compounds all dichloroacetate groups are monodentate. The bond valences considerations show that all 2,2′-bipyridine molecules are bonded almost 2 times stronger than carboxylate groups. In the structure of zinc compound exist O–H···O hydrogen bonds and in both structures can be found weak C–H···O hydrogen bonds. Additionally, both compounds are pile-stacked by π···π interactions. The IR spectra show typical vibrations for chelating 2,2′-bipyridine molecules and terminal monodentate carboxylate groups. The thermal decomposition studies show zinc compound decomposes in 4 steps and cadmium compound decomposes in 5 steps with formation of oxides as a final products. The ligands decompose gradually, first dichloroacetates and next 2,2′-bipyridine.     

Homo- and heterodinuclear 2,2′-bipyrimidine-bridged complexes

[M(hfacac)₂(bpym)] complexes, where M = Co^II, Ni^II or Zn^II, hfacac = hexafluoroacetylacetonate and bpym = 2,2bipyrimidine; and [Cl₂M(bpym)M(hfacac)₂] complexes, where M = Co^II, Ni^II Mn^II or ZnII M = Ni^II; M = NiII or Zn^II and M = Zn^II; M = Ni^II and M = Co^II have been prepared and characterized by chemical analysis, conductance measurements, IR and electronic spectroscopies and magnetic susceptibility measurements (4.2–292K range). The dinuclear NiII–Ni^II, Co^II–Ni^II and Mn^II–Ni^II complexes are antiferromagnetic, with an intramolecular exchange parameter, J, of –2.3–8.9cm–1. Co^II and Mn^II are in a high spin state. The low temperature effect observed in monomers and in Ni^II–Zn^II dimers is considered a consequence of either an intermolecular antiferromagnetic interaction or the zero-field splitting in NiII.     

Convenient Synthesis of 2,2′- and 4,4′-Methylenebisphenols with Bulky Alkyl Substituents and Evaluation of Their Antioxidant Activity

The work is devoted to a convenient procedure of the synthesis of 2,2′- and 4,4′-methylenebisphenols with alkyl substituents in heterogeneous catalysis. This compounds were obtained with yields up to 87% by reflux of 2,4- or 2,6-dialkylphenols with HCHO in n-octane in the presence of KSF clay. We found that the antioxidant activity on DPPH test for two novel methylenebisphenols having isobornyl fragments was comparable with control drugs.     

Isolation and Crystal Structure of Trans-2,2′,4,4′-tetramethyl-6,6′-dinitro Azobenzene

Trans-2,2′,4,4′-tetramethyl-6,6′-dinitro azobenzene (C16H16N4O4, Mr = 328.32) was isolated from benzene extract of the leaves of Aconitum sungpanense Hand. Mazz. as a new compound, and characterized by spectral methods and X-ray diffraction analysis. It crystallizes in monoclinic system, space group P21/c with a = 8.544(1), b = 13.997(2), c = 7.161(1) A, β = 112.97(1), V = 788.4(2)A3, Z = 4, Dc = 1.383 g/cm3, F(000) = 344 and μ(MoKα) = 0.102 mm-1. The final R = 0.0395 and wR = 0.1140 for 1913 independent reflections with Rint = 0.0109 and 1329 observed reflections with I > 2((I). The molecule is composed of two phenyl rings through trans N=N.