Electrochemical Properties of N-Substituted α-Diphenylphosphinoglycines

Russian Journal of Electrochemistry - The electrochemical properties of the N-substituted α-diphenylphosphinoglycines N-(2-methoxybenzyl) diphenylphosphinoglycine (1), N-(pyrazin-2-yl)...     

Study of Polyphenolic Compounds in Extracts from Flowers and Leaves of Canadian Goldenrod and Dwarf Goldenrod (Solidago canadensis L. and Solidago nana Nitt.)

Moscow University Chemistry Bulletin - The results of qualitative and quantitative determination of polyphenolic compounds, in particular flavon glycosides and flavon aglycones, in...     

Synthesis and X-ray structural investigations of 2-amino-7-methyl-4-(1-naphthyl)-5-oxo4H,5H-pyrano[4,3-b]pyran-3-carbonitrile and 2-amino-4-(1-naphthyl)-5-oxo-4H,5Hpyrano[3,2-c]chromene-3-carbonitrile

Synthesis and X-ray structural investigations have been carried out for the two title compounds C₂₀H₁₄N₂O₃ (4) and C₂₃H₁₄N₂O₃⋅C₂H₃N (5). Compound 4 crystallizes in the monoclinic space group P2₁/n, with a = 7.0542(5), b = 8.822(1), c = 24.833(2) ?, β = 94.30(4)^∘, V = 1541.0(4) ?³, and Z = 4. Compound 5 crystallizes with an acetonitrile solvent molecule in the monoclinic space group P2₁/n, with a = 11.075(1), b = 7.854(1), c = 22.703(2) ?, β = 90.67(1)^∘, V = 1974.5(3) ?³, and Z = 4. In both molecules, the 4H-pyran ring adopts a flattened-boat conformation. The naphthalene substituent occupies a pseudo-axial position and the dihedral angle with the flat part of the pyran ring is equal to 94.6(3) in 4 and 76.8(3)^∘ in 5. The mutual orientation of these fragments and the flatness of the heterocyclic rings lead to H⋅sH intramolecular steric interactions: H4A⋅sH18A 1.98 ? in 4 and 2.11 ? in 5. In the crystal of 4, intermolecular hydrogen bonds N–H⋅sO and C–H⋅sN link molecules into infinite tapes along the b axis. In the crystals of 5, intermolecular hydrogen bonds N–H⋅sO and C–H⋅sN link molecules into infinite layers parallel to the bc plane. In each case, the C–H⋅sN interaction can be considered to be a weak hydrogen bond. The acetonitrile molecules link via intermolecular weak C–H⋅sN hydrogen bonds to form infinite chains along the b axes.     

A Comparative Study of Acetonitrile Fraction Marker Substances from Leaves and Fruits of Malus sylvestris

The new plant raw material from leaves and fruits of Malus sylvestris is analyzed. It is shown that the content of substances extracted with acetonitrile amounted to 4.7–5.4% for leaves and 2.3–2.8% for fruits. The obtained extracts were used to identify substances, the presence of which is specific for the plant’s raw material and can be used in the future to identify raw material in crushed and powdered form. It is found that acetonitrile extract of Malus sylvestris is characterized by the presence of 10 peaks for fruits and 22 peaks for leaves, which can be considered as markers for the identification of medicinal plant material.     

Intramolecular Hypervalent X←X Interaction in Mono- and Bicyclic Heteroelement Compounds Containing Se and Te Atoms

Chalcogen-containing heterapentalene and quasimonocyclic compounds having SeÄSeÄSe and TeÄTeÄTe triads or SeÄSe and TeÄTe diads were studied by the ab initio [MP2(full)/6-31G**, MP2(fc)/6-31+G**, and MP2(fc)/LANL2DZ] and DFT methods (B3LYP/6-31G^**, B3LYP/6-31+G^**, and B3LYP/LANL2DZ). Heterapentalene compounds were found to be stable as planar bicyclic structures having a C _2v symmetry. The stability of quasimonocycic -chalcogenovinyl aldehydes increases with increase in the electron-acceptor power of the substituent at the X atom.     

The first heterometallic Cu(II)/Cr(III) complex with an open-chain Schiff-base ligand self-assembled from copper powder,Reineckes salt,ethylendiamine and acetone

A novel supramolecular assembly [{Cu(enac)}₂Cr(NCS)₄(NH₃)₂][Cr(NCS)₄(NH₃)₂]₃ · 4(CH₃)₂CO (enac = 4,6,6-trimethyl-3,7-diazanon-3-ene-1,9-diamine), the first example of a Cu/Cr heterometallic compound containing a Schiff-base ligand such as enac, and an anion of Reineckes salt, Cr(NCS)₄(NH₃)₂⁻, as a building block, was obtained by the self-assembly reaction of copper powder and Reineckes salt in an acetone/methanol (1:4) solution of ethylenediamine in the open air. An X-ray study shows that the complex includes a trinuclear Cu₂Cr cation, constructed from two Cu(enac)²⁺ moieties and a trans-[Cr(NCS)₄(NH₃)₂]⁻ block as a two-linking bridging ligand. The metal–metal separations within the cation are Cu?Cr = 6.393(31) Å and Cu?Cu = 12.786(63) Å. The supramolecular architecture of the complex involves two types of H-bonded chains, the first chain is generated by trinuclear cations [{Cu(enac)}₂Cr(NCS)₄(NH₃)₂]²⁺, [Cr(NCS)₄(NH₃)₂]⁻ anions and (CH₃)₂CO molecules, while the second by crystallographically different anions of Reineckes salt and (CH₃)₂CO. Variable-temperature (1.8–300 K) magnetic susceptibilities show a slight change of the μ_B value at low temperature, indicative of weak antiferromagnetic interactions (J_CuCr = −0.9 cm⁻¹) between the paramagnetic centers.     

Electrical conductivity and photoconductivity of film materials based on heteropolynuclear Cu/Cd complexes and organic polymers

We have studied the characteristic features of the electrical conductivity and photoconductivity of films of composites based on polyvinyl butyral and acrylonitrile butadiene styrene with added heteropolynuclear Cu/Cd complexes having one-dimensional and two-dimensional polymer structures and with added anthracene, epoxypropyl carbazole, and C₆₀ organofullerene molecules. Normal positive and abnormal negative effects of photoconductivity were found. Kinetic model of the photoconductivity was proposed. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 2, pp. 107–112, March–April, 2006.     

Carbamoylmethylphosphoryl Compounds: Ch-Acidity and Basicity

Abstract

Carbamoylmethylphosphoryl compounds (CMP) are used as neutral bifunctional extractants. However, little is known about acid-base properties of these compounds. We have studied CH-acidity and basicity of selected CMP, RR′P(O)CH₂C(O)NEt₂ with R,R′ = Alk, Alk₂N, Ar, AlkO, and also H-complexes of CMP with HNO₃.