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Nina V Podberezskaya

Publications and source records attributed to Nina V Podberezskaya.

6 recordsLinked to original sources
PubMed2005

Bis[N-(2-hydroxyethyl)-beta-alaninato]copper(II).

The Cu(II) ion in the title complex, [Cu(C5H10NO3)2] or [Cu(He-ala)2] [He-ala = N-(2-hydroxyethyl)-beta-alaninate], resides at the inversion centre of a square bipyramid comprised of two facially arranged tridentate He-ala ligands. Each He-ala ligand binds to a Cu(II) ion by forming one six-membered beta-alaninate chelate ring in a twist conformation and one five-membered ethanolamine ring in an envelope conformation, with Cu-N = 2.017 (2) angstroms, Cu-O(COO) = 1.968 (1) angstroms and Cu-O(OH) = 2.473 (2) angstroms. The [Cu(He-ala)2] molecules are involved in a network of O-H...O and N-H...O hydrogen bonds, forming layers parallel to the (10-1) plane. The layers are connected into a three-dimensional structure by van der Waals interactions, so that the molecular centres form pseudo-face-centered close packing.

Journal Article↗
PubMed2005

The bivalent metal hypophosphites Sr(H2PO2)2, Pb(H2PO2)2 and Ba(H2PO2)2.

The structures of isomorphous monoclinic strontium and lead bis(dihydrogenphosphate), Sr(H2PO2)2 and Pb(H2PO2)2, and orthorhombic barium bis(dihydrogenphosphate), Ba(H2PO2)2, consist of layers of hypophosphite anions and metal cations exhibiting square antiprismatic coordination by O atoms. The Sr and Pb atoms are located on sites with point symmetry 2, and the Ba atoms are on sites with point symmetry 222. Within the layers, each anion bridges four metal cations.

Journal Article↗
PubMed2004

The alkali hypophosphites KH2PO2, RbH2PO2 and CsH2PO2.

The structures of the hypophosphites KH(2)PO(2) (potassium hypophosphite), RbH(2)PO(2) (rubidium hypophosphite) and CsH(2)PO(2) (caesium hypophosphite) have been determined by single-crystal X-ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous.

Journal Article↗
PubMed2002

Hexaaquanickel(II) bis(hypophosphite).

The structure of hexaaquanickel(II) bis(hypophosphite), [Ni(H(2)O)(6)](H(2)PO(2))(2), has been determined. The crystals are prismatic. The packing of the Ni and P atoms (not the entire hypophosphite anions) is the same as in the structures of [Co(H(2)O)(6)](H(2)PO(2))(2) and [Co(0.5)Ni(0.5)(H(2)O)(6)](H(2)PO(2))(2). The Ni(II) cations have a pseudo-face-centered cubic cell, with cell parameter a approximately= 10.216 A and tetrahedral cavities occupied by P atoms. The Ni(II) cation has crystallographically imposed twofold symmetry and has an octahedral coordination sphere consisting of six water O atoms, two of which also lie on the twofold axis. The planes of oppositely coordinated water molecules are in a cross conformation. The geometry of the hypophosphite anion is close to point symmetry mm2. The hypophosphite anions are hydrogen bonded to the coordinated water molecules.

Journal Article↗
PubMedDate not supplied

Complexation models of N-(2-carboxyethyl)chitosans with copper(II) ions.

The copper(II) complex formation equilibria of N-(2-carboxyethyl)chitosans with three different degrees of substitution (DS = 0.42, 0.92, and 1.61) were studied in aqueous solution by pH-potentiometric and UV-spectrophotometric techniques. It was demonstrated that the complexation model of CE-chitosans depends on DS: the [Cu(Glc-NR(2))(2)] complexes are predominant for two lower substituted samples ("bridge model", log beta(12) = 10.06 and 11.6, respectively), whereas the increase of DS leads to formation mainly of the [Cu(Glc-NR(2))] complexes ("pendant model", log beta(11) = 6.41). As a model for copper complexation with a disubstituted residue of CE-chitosan, the complex of N-methyliminodipropionate [CuMidp(H(2)O)].(H(2)O) was synthesized and structurally characterized by XRD. The unit cell consists of two crystallographically nonequivalent Cu atoms having slightly distorted square pyramidal coordination; Midp constitutes the basal plane of the pyramid and acts as a tetradentate NO(3) chelate-bridging ligand by the formation of two six-membered chelate rings (average Cu-O 1.99 A, Cu-N 2.04 A) and a bridge via carbonyl O atom (average Cu-O 1.99 A), an apical position is occupied by a water molecule (average Cu-Ow 2.30 A).

Carbohydrate Conformation↗