Spin-peierls transition in dimerized stacks of anion-radical salt (N-Me-2,5-di-Me-Pz)(TCNQ)2, (Pz is pyrazine)

An anion-radical salt (ARS) (N-Me-2,5-di-Me-Pz)(TCNQ)₂, where Pz is pyrazine, was synthesized and its crystal structure was resolved. X-ray diffraction experiments on single crystals were performed. Heat capacity was measured in the temperature range from 2 to 300 K. Magnetisation and magnetic susceptibility were measured in the temperature range from 2 to 300 K and the low-temperature part was measured in magnetic fields from 5 mT to 5 T. The experimental results were explained in terms of dimerized Heisenberg spin chain model. Numerical calculations were performed and compared with experimental data.     

Two-gap magnetic structure of the two-stack anion-radical salt (N-Me-3,5-Di-Me-Py)(TCNQ)2 (Py is pyridine)

We performed the synthesis of a (N-Me-3,5-di-Me-Py)(TCNQ)2 single crystal and we resolved the crystallic and molecular structure of this salt. Magnetic susceptibility measurements were performed in the temperature range 2-300 K. The results are studied with respect to two energy gaps in the magnetic excitations spectra which could signify that the Peierls dielectric phase forms in two grades.     

Ion Exchange Properties of Günterblassite and Gmelinite,Prototypes of Microporous Materials for Water Purification

Russian Journal of Applied Chemistry - Processes and products of ion exchange of günterblassite (K,Ca,Ba,Na)3–xFe1–y[(Si,Al)13O25(OH,O)4]·7H2O (microporous silicate,...     

Heterometallic Cr2/Ag2 1D polymer: Synthesis,structure and properties

A 1D heterometallic Cr₂/Ag₂ polymer formulated as {[Ag(μ-H₂O)Ag(nta)Cr(μ-OH)(μ-AcO,O′)Cr(nta)]·H₂O}_n (1) (H₃nta = nitrilotriacetic acid) has been prepared and structurally characterized. {Cr(μ-OH)(μ-OAc)Cr} dimeric units containing two different bridging ligands, hydroxo and acetate groups are coordinated to six Ag atoms forming the 1D network. The temperature dependence of magnetic susceptibility for 1 which was fitted with an isotropic Hamiltonian including biquadratic exchange parameters, yielded antiferromagnetic interaction parameters (J = −8.5(1), j = −0.50(7) cm⁻¹ g = 2.0).     

Investigation of the reaction of 1-methylimidazoline-2-thione with molecular iodine

The reactions of 1-methylimidazoline-2-thione and its chemical oxidation product, viz., 2,2′-dithiobis(1-methylimidazolin-2-yl) diiodide, with molecular iodine were studied by UV-Vis spectroscopy. The crystal and molecular structure of the compound of composition [(C₃H₂N₂)(HCH₃)S]₂(I₃)₂I₂ was established by X-ray diffraction. In the crystal structure, the dications and the triiodide anions form mixed stacks, between which iodine molecules are located. The dications, anions, and iodine molecules are linked by numerous intermolecular interactions to form three-dimensional supramolecular associates.     

1-Dimethylamino-2,7-dimethoxy-8-methylamino-3,5-dinitronaphthalene and 1,2,4-tribromo-6-dimethylamino-5-methylaminoacenaphthylene: first examples of N—H...N hydrogen bond contraction/expansion in neutral 1,8-diaminonaphthalenes

1-Dimethylamino-2,7-dimethoxy-8-methylamino-3,5-dinitronaphthalene and 1,2,4-tri-bromo-6-dimethylamino-5-methylaminoacenaphthylene containing the N,N,N′-trimethyl-1,8-diaminonaphthalene fragment with the substituted aromatic ring were studied by X-ray diffraction. Both systems are stabilized by an intramolecular hydrogen bond. The characteristics of the latter are determined by the influence of either the ortho substituents or the peri-annelated five-membered ring. In the former case, the intramolecular hydrogen bond is substantially shortened (N...N, 2.628(5) Å) due to the “buttressing effect” of the o-OMe groups, whereas the peri-dibromoethylene bridge and the Br substituent at position 4 cause a substantial elongation of the intramolecular hydrogen bond (N...N, 2.75(2) and 2.76(1) Å) in the latter case. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2414–2417, November, 2005.     

Molecular and crystal structure and stability of triiodides of quinolinium derivatives

1,2,4-Trimethylquinolinium triiodide (I) and 1-ethyl-2,4-dimethylquinolinium (II) triiodide are synthesized and studied by X-ray diffraction analysis. The layered structures of compounds I and II are formed by mixed stacks of cations and anions. Crystals of compound II consist of two types of anionic chains. The coordinating ability of the corresponding organic iodides toward molecular iodine in chloroform solutions is studied.     

The Crystal Structure of a RAS (N–CH3-2-NH2-5-Cl–Py)(TCNQ)(CH3CN) Solvate

Crystallography Reports - The structure of the radical anion salt (RAS) of 7,7,8,8-tetracyanedimethane (TCNQ) with a cation based on 2-amin-5-chloro-pyridine (2-NH2-5-Cl–Py, Am), that is,...     

Cyanoacetylene and Its Derivatives: XXXIII. One-Pot Stereoselective Synthesis of Bis-iminodihydrofurans from 4-Hydroxy-4-methyl-2-pentynonitrile and Aromatic Amines

4-Hydroxy-4-methyl-2-pentynonitrile reacts with aniline, N-methylaniline, and 2-naphthylamine under mild conditions (20–80°C) to afford the corresponding 4-arylamino-2-(2-imino-5,5-dimethyl-2,5-dihydro-4-furylimino)-5,5-dimethyl-2,5-dihydrofurans in one preparative step. According to the X-ray diffraction data, both imino groups in the products have syn configuration with respect to the ring oxygen atom.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 6, 2005, pp. 903–909.Original Russian Text Copyright © 2005 by Trofimov, Mal’kina, Shemyakina, Kudyakova, Sokolyanskaya, Sinegovskaya, Albanov, Smirnov, Kazheva, Chekhlov, D’yachenko.