Dmitry Yu. Naumov

Syntheses, Structures, and Electrochemical Properties of Inclusion Compounds of Cucurbit(8)uril with Cobalt(III) and Nickel(II) Complexes

Inclusion compounds of a macrocyclic cavitand cucurbit[8]uril (CB[8]) with cobalt(III) and nickel(II) complexes of 1,3-diaminopropane (tn) and 1,3-diamino-2-propanol (tmOH) { trans-[Co(tn) 2Cl 2]@CB[8]}Cl.14H 2O ( 1), { trans-[Co(tmOH)(tmO)]@CB[8]}Cl 2.22H 2O ( 2), and { trans-[Ni(tmOH) 2]@CB[8]}Cl 2.22H 2O ( 3) were synthesized and characterized by X-ray single crystal analysis, IR spectroscopy, ESI-MS, and by solid-state stripping voltammetry. The encapsulation of trans-[Co(tn) 2Cl 2] (+) within the cavity of CB[8] stabilizes the complex toward ligand substitution reactions in aqueous solution. The electrochemical study demonstrates that CB[8] prefers the oxidized species in trans-[Co(tn) 2Cl 2] (+)/ trans-[Co(tn) 2Cl 2] (0) and trans-[Co(tmO)(tmOH) 2] (2+)/ trans-[Co(tmO)(tmOH) 2] (+) redox couples, but stabilizes the reduced form trans-[Ni(tmOH) 2] (2+) against the oxidized species. The reversibility of voltammogram shapes evidence that for the inclusion compounds 1- 3 electron transfer reactions proceed within the cavity of the host.

Synthesis and crystal structure of Cu(II) complex with 4-(pyridyl-2)-1,2,4-triazole

Abstract The synthesis and X-ray structure of new Cu(II) complex with 4-(pyridyl-2)-1,2,4-triazole (pytrz) are reported. The crystal structure of [Cu3(pytrz)8(H2O)4](NO3)6 has been determined by X-ray diffraction. Crystals are triclinic, space group P-1, unit cell parameters are: a=11.971(2), b=13.079(3), c=14.439(2) A , α=114.03(1), β=97.79(1), γ=111.02(1)°, V=1819.2(6) A 3 , Z=1, Rf=0.0706. The structure consists of linear trinuclear cations with a +6 charge and six noncoordinated NO3− anions. The central copper(II) atom is located on an inversion centre and is coordinated by six nitrogen atoms of pytrz molecules bridging via the nitrogen atoms in the N 1 , N 2 positions. Each external copper(II) atom completes its coordination sphere with one monodentate pytrz via the nitrogen atom in the N1 position and two coordinated water molecules.

Crystal Growth, Structure, and Optical Properties of LiGaGe2Se6

Large single crystals of LiGaGe2Se6 were grown, and their structure and linear optical properties were studied. According to XRD results there is some disorder because of the Li ion fluctuation and their redistribution along two cationic sites. The shape of the fundamental absorption edge versus temperature was analyzed, and direct band gap values were estimated from the Tauc plots. Raman spectra were recorded and compared with results of ab initio calculations. The high quality of LiGaGe2Se6 crystals is confirmed by signals from free and self-trapped excitons. Photoluminescence in the 696 nm broad band and a set of bands in the 950 to 1100 nm range are related to self-trapped excitons and cation antisite defects, respectively. The luminescence intensity increases two orders as the crystal is cooled to 80 K. Four peaks are observed in the thermoluminescence curves with dominant ones at 218 and 410 K. Pyroelectric luminescence in the 100 to 180 K range confirms the noncentrosymmetric structure of this crystal.

Cd2+ complexation with P(CH2OH)3, OP(CH2OH)3, and (HOCH2)2PO2(-): coordination in solution and coordination polymers.

The coordination of Cd(2+) with P(CH(2)OH)(3) (THP) in methanol was followed by (31)P and (111)Cd NMR techniques. A cadmium-to-phosphine coordination ratio of 1:3 has been established, and effective kinetic parameters have been calculated. Air oxidation of THP in the presence of CdCl(2) at room temperature produces coordination polymer (3)(∞)[Cd(3)Cl(6)(OP(CH(2)OH)(3))(2)] (1). The same oxidation reaction at 70 °C gives another coordination polymer, (∞)[CdCl(2)(OP(CH(2)OH)(3))] (2). Complexes 1 and 2 are the first structurally characterized complexes featuring OP(CH(2)OH)(3) as a ligand that acts as a linker between Cd atoms. The addition of NaBPh(4) to the reaction mixture gives coordination polymer (∞)[Na(2)CdCl(2)(O(2)P(CH(2)OH)(2))(2)(H(2)O)(3)] (3) with (HOCH(2))(2)PO(2)(-) as the ligand. Coordination polymers 1-3 have been characterized by X-ray analysis, elemental analysis, and IR spectroscopy.

Unexpected ligand substitutions in the cluster core {Re6Se8}: synthesis and structure of the novel cluster compound Cs11(H3O)[Re6Se4O4Cl6]3·4H2O

The compound Cs11(H3O)[Re6Se4(O)4Cl6]3.4H2O containing a novel cluster core {Re6Se4(O)4} with ordered ligands, where the 4 positions of one face of a Se4(O)4 cube are occupied exclusively by Se atoms and 4 O atoms lie in the opposite face was synthesized via the interaction of solid Re6Se8Br2 with molten KOH.

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.

Iron(III) dihydrogenphosphate(I)

The structure of rhombohedral (R3) iron(III) tris[dihydrogenphosphate(I)] or iron(III) hypophosphite, Fe(H2PO2)3, has been determined by single-crystal X-ray diffraction. The structure consists of [001] chains of Fe3+ cations in octahedral sites with -3 symmetry bridged by bidentate hypophosphite anions.

A urea complex of copper(II) hypophosphite at 293, 100 and 15 K

The crystal structure of poly[copper(II)-di-mu-hypophosphito-mu-urea], [Cu(H2PO2)2(CH4N2O)]n, has been determined at 293, 100 and 15 K. The geometry of the hypophosphite anion is very close to ideal, with point symmetry mm2. Each Cu atom lies on an inversion centre and is coordinated to six O atoms from four hypophosphite anions and two urea molecules, forming a tetragonal bipyramid. The unique urea molecule lies on a twofold axis. Each hypophosphite anion in the structure is coordinated to two Cu atoms. The hypophosphite anions, urea molecules and Cu(II) cations form polymeric ribbons. The Cu(II) cations in the ribbon are linked together by two hypophosphite anions and a urea molecule, which is coordinated to Cu via an O atom. The ribbons are linked to each other by N-H...O hydrogen bonds and form polymeric layers.

LiBaAlF6 and the crystal chemistry of LiAIIBIIIF6 phases.

Lithium barium hexafluoroaluminate (LBAF), LiBaAlF(6), is a new member of the large family of compounds of formula LiA(II)B(III)F(6). These materials display a variety of structures depending on the sizes of the A and B cations. LiBaAlF(6), which is isomorphous with LiBaCoF(6), belongs to the monoclinic P2(1)/c subset and has a three-dimensional network structure consisting of distorted LiF(4)(3-) tetrahedra corner-sharing with AlF(6)(3-) octahedra and BaF(12) polyhedra. All of the atoms reside on general positions. An analysis of the ionic radii of the A cations versus formula volumes for the known members of the family yields a structure map that reasonably segregates the compounds by space group. The data obtained are thus suitable for predicting new isomorphic crystal structures.

Cadmium bis­[dihydrogenphosphate(I)]

# 2005 International Union of Crystallography Printed in Great Britain – all rights reserved The structure of monoclinic (C2/c) cadmium bis[dihydrogenphosphate(I)], [Cd(H2PO2)2], consists of layers located at x = 0 and 12. The Cd cation has a distorted octahedral coordination and dihydrogenphosphate(I) anions act as tridentate bridging ligands. The Cd atoms are on sites of twofold symmetry, while all other atoms are in general positions. The compound is isotypic with Ca(H2PO2)2 [Goedkoop & Loopstra (1959). Ned. Tijdschr. Natuurkd. 25, 29–41].