First example of the Chan—Lam—Evans N-arylation of bispidines

Russian Chemical Bulletin - The N-arylation of N-Boc-bispidine with arylboronic acids was accomplished under the copper-catalyzed Chan—Lam—Evans reaction conditions. The reaction...     

Experimental Charge Density Evidence for Pnicogen Bonding in a Crystal of Ammonium Chloride

Chemical binding in crystalline ammonium chloride, a simple inorganic salt with an unexpectedly complex bonding pattern, was studied by using a topological analysis of electron density function derived from high‐resolution X‐ray diffraction. Supported by periodic quantum chemical calculations, it provided experimental evidence for weak σ‐hole bonds (1.5 kcal mol^?1) that involve ammonium cations in a crystal. Our results show this type of supramolecular interaction to be more numerous than has been found to date by using gas‐phase calculations or statistical analysis of CSD.     

ACID SODIUM SALT OF 1H-PYRAZOLE-3,4,5- TRICARBOXYLIC ACID: SYNTHESIS,CRYSTAL STRUCTURE AND FEATURES OF INTRAMOLECULAR BONDS

Journal of Structural Chemistry - The oxidation reaction of 3,3′,5,5′-tetramethyl-1H,1′H-4,4′-bipyrazole in the HNO3–Fe3+ system unexpectedly resulted in the formation...     

The nature of chemical bonding in nitramide

The spatial and electronic structure studies of nitramide NH₂NO₂ suggest that the change in its molecular geometry upon transition from the gas phase to the condensed state is caused by an increase in the contribution of conjugation between functional groups. According to the analysis of the Bader atomic charges, the effects of such conjugation are to a considerable extent governed by intramolecular charge transfer from the amino to the nitro group. From estimation of the contribution of conjugation to the charge transfer it follows that conjugation remains in the isolated molecule. The influence of hydrogen bonding on the increase in the contribution of conjugation and the corresponding charge redistribution in the molecule was considered. Despite the presence of conjugation between functional groups, the planar configuration of the molecule in the crystal is not realized and the crystallographic twofold axis corresponds to superposition of two molecular configurations with C _s symmetry.     

New potentially tridentate amidinate ligand {o-MeOC6H4NC(Ph)N(SiMe3)}?. Synthesis and molecular structures of amidinate complexes of lithium [{o-MeOC6H4NC(Ph)N(SiMe3)}Li]2 and yttrium [{o-MeOC6H4NC(Ph)N(SiMe3)}YCl2(THF)2]2

The reaction of lithium silylamide [??o-MeOC₆H₄N(SiMe₃)}Li(OEt₂)]₂ with 2 equiv. of benzonitrile in THF at ??20 °C affords the lithium derivative of the new tridentate amidinate ligand [{o-MeOC₆H₄NC(Ph)N(SiMe₃)}Li]₂. The X-ray diffraction study showed that this complex has a dimeric structure due to the coordination of the N atoms and the ether group of one amidinate ligand to different Li atoms. The reaction of anhydrous YCl₃ with the resulting complex in THF gives the monoamidinate complex [{o-MeOC₆H₄NC(Ph)N(SiMe₃)}YCl₂(THF)₂]₂ regardless of the reagent ratio. The latter has a dimeric structure in the crystalline state as a result of the presence of two ??₂-bridging Cl atoms that link Y atoms. The ether groups of the amidinate ligands are not involved in the metal-ligand interaction.     

Synthesis and thermal stability of imino-1,3-dithietanes. Influence of structural factors

The reaction of 1,2-dithiol-3-thiones with isonitriles at room temperature affords imino-1,3-dithietanes. The reaction is reversible. According to ¹H NMR spectroscopy, the rise of the temperature shifts the equilibrium to the starting compounds. The structure of one of the imino-1,3-dithietanes was established by X-ray diffraction.     

Insertion of carbon disulfide and the nitrile group into the diaziridine ring of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes in ionic liquids catalyzed by BF<Subscript>3</Subscript> · Et<Subscript>2</Subscript>O

The present study revealed two new reactions resulting in the diaziridine ring expansion, viz., the insertion of the CS₂ molecule and the CN group of activated nitriles into the C—N bond of the diaziridine fragment of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes. These reactions can be performed only in ionic liquids in the presence of BF₃ · Et₂O as the catalyst. Based on these reactions, we developed simple one-pot methods for the synthesis of 3-aryldihydro-5 H-pyrazolo[1,2- c][1,3,4]thiadiazole-1-thiones and 1-aryl-6,7-dihydro-1 H,5H-pyrazolo-[1,2-a][1,2,4]triazoles in high yields. Dipolar intermediates of new reactions, which are direct precursors of the final products, were detected by NMR methods. One of the intermediates was isolated and characterized. The reaction of 6-aryl-1,5-diazabicyclo[3.1.0]hexanes with benzoyl cyanide affords (2-benzoyrpyrazolidin-1-yl)(aryl)acetonitriles.     

First synthesis of 1,5-diazabicyclo[3.1.0]hexane complexes with cadmium salts

Complexes of bicyclic diaziridines 6,6′-bi(1,5-diazabicyclo[3.1.0]hexane) (L ¹ ) and 6-(4-methoxyphenyl)-1,5-diazabicyclo[3.1.0]hexane (L ² ) with the salts Cd(NO₃)₂ · 4H₂O and Cd(ClO₄)₂ · 6H₂O have been synthesized. The fact of complexation has been established by cyclic voltammetry. The crystal structure of complex L ¹ with Cd(NO₃)₂ (the coordination number of cadmium is 8) has been studied by X-ray diffraction.     

Furazan-containing bromoarenes in the Suzuki-Miyaura reaction

The palladium-catalyzed cross-coupling reactions of 3-[bromo(het)aryl]furazans and bromobenzofurazans with arylboronic acids afford target biaryls in good yields. 3-Bromo-4-phenylfurazan containing a bromine atom in the furazan ring undergoes decomposition under the reaction conditions.     

Hydrates and ammonium salts of 4-nitrobenzenesulfonic acid: supramolecular organization and its relation to proton conductivity

Structural features, the crystal packing, and the proton conductivity of a series of hydrates and ammonium salts of 4-nitrobenzenesulfonic acid were studied. It was shown that infinite cation associates containing the onium moiety are responsible for a substantial increase in the proton conductivity. The nature of the disorder in a series of crystals was investigated by performing X-ray diffraction studies at different temperatures. A new type of structural synthons, viz., anion-anion dimers stabilized by the SO₃ ⁻…NO₂ interaction, was found and characterized and the role of solvent water molecules was elucidated based on high-resolution X-ray diffraction data. The water molecules serve mainly as channels for charge transfer from the cation to the anion with retention of the electroneutrality.