Oleg A. Dyachenko

NIR-fluorescent coumarin-fused BODIPY dyes with large Stokes shifts

A series of novel non-symmetrical coumarin-fused BODIPY dyes were synthesised. Their absorption and emission properties are strongly influenced by substitution in the coumarin moiety. Diethylamino-substituted dyes showed near-IR emission with large Stokes shifts (up to 144 nm) and good fluorescence quantum yields.

Asymmetric nitrogen−35 : Structure and properties of l(s)-α-carboxyethyl-3, 3-bis(trifluoromethyl)diaziridine and its derivatives

Abstract A second-kind asymmetric transformation involving N-atom inversion has been observed at 20° for 1(S) - α - carboxyethyl - 3,3 - bis(trifluoromethyl)diaziridine 1 and its methyl ester 2. X-Ray data for the diastereomer (1S, 2S, α-S), 1A (which is thermodynamically preferred in the crystalline phase), 1H NMR spectra of ethyl ester 3-15N(1) and 3-15N(2), CD spectra of 1A,B, 2A,B, potassium salt 4A,B and semiempirical calculations (MINDO/3 and INDO) for 1A, show that the stereospecificity of crystallization of the diastereomer A is due to the higher energy of the crystal lattice of the diastereomer (1R, 2R, α-S), 1B because of hindered charge compensation as well as to the hindrance by the CF3, groups to intermolecular H-bonds. According to semiempirical calculations, the stability of 3,3 - bis(trifluoromethyl) - diaziridines (TFD) to the action ofel w-orbital energies and depolarization of the C-N bonds due to hyperconjugation and the inductive effect of the CF3,-groups. The steric effect of these groups is the reason of the low configurational stability of TFD compared with the 3,3-dimethyl analogues.

Molecular metals based on Pd(dddt)2 and Ni(dddt)2 complexes

Abstract A series of electroconducting cationic salts based on the Pd(dddt) 2 and Ni(dddt) 2 complexes has been synthesized. The first stable molecular metals have been found among the M(dddt) 2 salt family.

A Domino Reaction of α,β-Acetylenic γ-Hydroxy Nitriles with Arenecarboxylic Acids: An Unexpected Facile Shortcut to 4-Cyano-3(2H)-furanones

An unexpected facile domino reaction of alpha,beta-acetylenic gamma-hydroxy nitriles with arenecarboxylic acids (Et(3)N, MeCN, 20-25 degrees C, 48 h) affords 4-cyano-3(2H)-furanones in 67-86% yield. The reaction is triggered by the addition of an arenecarboxylic acid to a triple bond, followed by the domino reaction sequence: intramolecular transesterification-enol formation and Claisen condensation of the ketoacetonitrile tautomer with ester functional group.

Asymmetrical nonbridgehead nitrogen—XXIV: Complete separation into antipodes and absolute configuration of chiralic N-alkoxyaziridines

Optically active derivatives of 1 - methoxyaziridine - 2,2 - dicarboxylic acid have been obtained: the diethyl ester S-(− 1a) by kinetic enrichment under the action of 1-ephedrine; the diamines R-(+2d) and S-(−2f) by crystallization from 1-methyllactate; the diamide S-(−2g) by asymmetric inversion reaction at the N atom while heating in 1-methyllacetate. The basic possibility of 1-alkoxyaziridine reactions with retention of optical activity (ammonolysis and reduction with LAH4) has been demonstrated for S-(−1a) and R-(+1). 1-Methoxy - aziridine - 2,2 - dicarboxylic acid cis-ethyl ester 4 has been completely separated into antipodes 1R, 2S-(+4) and 1S, 2R-(−4) which under the effect of diazoethane afford diethyl esters R-(+1) and S-(−1) with optical purity of 96.2 and 93.8% (determined by PMR using a chiralic shift-reagent). On the basis of X-ray analysis of monoamides of 1 - methoxyaziridine - 2,2 - dicarboxylic acid ethyl ester and of salt +7 the trans-specificity of ammonolysis and hydrolysis of 1 and the absolute configurations of all the optically active derivatives obtained were established.

The M(dddt)2 family of conducting complexes: [Ni(dddt)2]3(AuBr2)2, the first quasi-two-dimensional metal stable down to at least 1.3 K

The first stable molecular metal, [Ni(dddt)2]3(AuBr2)2, among the M(dddt)2 family of conducting charge-transfer salts has been prepared and its crystal structure has been solved by X-ray analysis. The origin of the metallic conductivity of [Ni(dddt)2]3(AuBr2)2 as well as the stability of this salt with respect to metal-to-insulator transitions is explained on the basis of tight-binding band structure calculations.

A new series of ET-based organic metals: Synthesis, crystal structure and properties

Abstract New two-dimensional organic metals ET 2 [Hg(SCN) 3−n X n ], X=F, Cl, Br, I have been synthesized and investigated. ET 2 [Hg(SCN)Cl 2 ] and ET 2 [Hg(SCN) 2 X] (X=Cl, Br or (0,33 Cl+0, 66 Br) have been found isostructural. Cationic sheets of x -type alternate with anionic sheets. The [Hg(SCN) 3−n X n ] − (n=1,2) anions have a polymeric-structure and form chains with one or two SCN bridge ligands. The conductivity of salts with X=F is of a metallic character down to helium temperature, while all salts with X=Cl(n=1,2), (Cl 0,33 Br 0,66 ), Br exhibit metallic behaviour of their conductivity till 35, 50, 70 and 140 K, respectively, then they become insulators The salt with X=I is semiconductor.

Crystal structure and molecular packing in a new organic semiconductor penta[bis(ethylenedithio)tetrathiafulvalene]-hexathiocyanatomononitratoyttrium(III)-ethanol

Abstract A new radical cation (ET)5[Y(NCS)6NO3]·C2H5OH salt was prepared by electrochemical oxidation of ET in a chlorobenzene–ethanol solution. Its crystal structure and conducting properties were examined. The salt has a layered crystal structure with a new type of molecular packing in the radical cation layer, which was called the ω-type. The observed electroconducting properties suggest that this salt is a semiconductor.

New organic metal (BEDO-TTF)4Pt(CN)4·H2O

Abstract A new charge transfer salt of (BEDO-TTF) 4 Pt(CN) 4 ·H 2 O (BEDO-TTF = bis(ethylenedioxo)tetrathiafulvalene) composition has been prepared. X-ray analysis shows that the conducting donor layers of new θ″-type packing alternate with anion sheets composed of [Pt(CN) 4 ] −2 anions, which are associated with H 2 O molecules via hydrogen bonds. Temperature and magnetic field dependences of the resistance are presented.

Novel packing type of ET radical cation layers in a new organic conductor (ET)5[Dy(NCS)6NO3]·C2H5OH with a metal-complex lanthanide anion

Abstract A new radical cation (ET) 5 [Dy(NCS) 6 NO 3 ]·C 2 H 5 OH salt was prepared by electrochemical oxidation of ET in a chlorobenzene–ethanol solution. Its crystal structure and conducting properties were examined. The salt has a layered crystal structure with a basically new packing type of the radical cation layer, which was called an ω-type. Resistance studies reveal a semiconducting nature of this salt.