Stereochemistry of the citrate anion in compounds containing guanidinium and citrate ions

Journal of Structural Chemistry - An analysis is presented for the results obtained in the studies initiated by A. E. Shvelashivili, Corresponding Member, Academy of Sciences of Georgia, and...     

Synthesis and structure of copper(II) trans-diaqua-bis(3-hydroxybenzoylhydrazine) nitrate dihydrate [Cu(C7H8O2N2)2(OH2)2](NO3)22H2O

Synthesis of [Cu(m-HBH)₂(OH₂)₂](NO₃)₂·2H₂O, where m-HBH = C₇H₈O₂N₂ (3-hydroxybenzoylhydrazine), is described. The structure of the compound was studied by X-ray phase analysis and IR spectroscopy; crystal data are a = 57.415(6) Å, b = 19.760(2) Å, c = 7.586(2) Å; Fdd 2, Z = 16, R(F) = 0.053. The compound consists of [Cu(m-HBH)₂(OH₂)₂]²⁺ complex cations, NO ₃ ^? anions, and two water molecules. The similarity between the IR spectra of Cu(m-HBH)₂(NO₃)₂·nH₂O and Co(m-HBH)₂(NO₃)₂·5H₂O, element analysis data, and crystal data obtained at the first stage of X-ray analysis show that the structures and compositions of these compounds are identical relative to the type of surroundings of the central atom. In contrast to the cobalt compound [Co(m-HBH)₂(OH₂)₂](NO₃)₂·3H₂O, in which the cobalt atom has a nearly regular octahedron as a coordination polyhedron, the copper(II) compound has a square bipyramid around the copper atom; c.n. is 6 = 4 + 2 (planar distances: 2.013(2) Å, 2.021(2) Å, 2.033(3) Å, 2.087(3) Å; axial distances: 2.367(3) Å, 2.374(3) Å) and lacks one crystallization water molecule.     

Crystalline and molecular structure of diaminoguanidinium tetrachlorozincate

A single-crystal X-ray diffraction study of a single crystal of the composition (AgunH)₂[ZnCl₄], where AgunH = (NH₂)₂C-NH-NH₂)⁺, has been performed. Crystals are monoclinic, space group P2₁/c, Z = 4, a = 7.642(2) Å, b = 24.123(4) Å, c = 7.496(2) Å, β = 81.77(2)°, V = 1368.0(2) ų, T = 293 K. The finite value R = 0.045 was obtained for 1878 independent reflections with I > 3σ(I). The structure was built from cations of aminoguanidinium and tetrahedral complex anions [ZnCl₄]^2?.     

Structure of tetra(3,5-dinitrobenzoate) bis(Piperidine) hexaaquanickel(II)—[Ni(OH2)6](PipH)2(3,5-DNB)4·2H2O dihydrate

It is found that M(AmH)₂(3,5-DNB)₄·8H₂O compounds (where M(II) = Co, Ni; AmH is piperidine PipH = (C₅H₁₀NH₂)⁺ or diethylamine DaH = (C₄H₁₀NH₂)⁺ cations; 3,5-DNB = (C₇H₃N₂O₆)⁻ is the dinitrobenzoic acid anion) are isotypic. The structure of the Ni(PipH)₂(3,5-DNB)₄·8H₂O single crystal is studied. The crystals have a monoclinic system, P2₁/n space group, Z = 2, a = 6.7694(3) ?, b = 16.0746(6) ?, c = 23.1250(9) ?, β = 97.794(1)°, V = 2493.1(2) ?³, T = 153 K. The final value R(F) = 0.0407 was obtained for 8191 independent reflections with I> 2σ(I). The structural units of the compound studied are as follows: [Ni(OH₂)₆]²⁺ complex hexaaquacation, two (PipH)⁺ cations, four (3,5-DNB)⁻ anions, and two molecules of water of crystallization with the structural formula [Ni(OH₂)₆](PipH)₂(3,5-DNB)₄·2H₂O. Similar compounds of Ni(II) and Co(II) are isostructural.     

Crystal structure of bis[Ba(Aet)(OH2)5]bis(Aet)·4H2O

An X-ray crystallographic study is conducted of single crystals with the composition [Ba₂(Aet^?)₂·10(H₂O)]²⁺·2(Aet^?)·4H₂O, where Aet^? = (C₁₀H₁₁N₄O₂S₂)^? is the ethazole (2-(para-aminobenzenesulfamido)-5-ethyl-1,3,4-tiadiazole) anion. The crystals are monoclinic; the space group is P2₁/c, Z = 2; a = 9.793(2) Å, b = 15.408(4) Å, and c = 22.553(6) Å; β = 94.98(2)°; and R = 0.047. The independent part of the compound’s structural formula, [Ba(Aet)(OH₂)₅](Aet)·2H₂O, is isostructural with the analogous compound with the Sr atom. The ethazole anion is coordinated to the complexing metal atom by oxygen and nitrogen atoms to form a four-membered ring.     

Structure of bis(hexamethylenetetramine) hexaaquanickel(II)hexafluorotitanate(IV) monohydrate — [Ni(OH2)6][TiF6](Ur)2·H2O

The X-ray diffraction study of a single crystal with the composition NiTiF₆(Ur)₂·7H₂O is performed, where Ur = C₆H₁₂N₄ is an urotropine (hexamethylenetetramine) molecule. The compound crystallizes in the triclinic P-1 space group: a = 8.7220(5) Å, b = 9.1004(5) Å, c = 17.533(1) Å, α = 75.074(1)°, β = 88.530(1)°, γ = 62.558(1)°, Z = 2, d _x = 1.756 g/cm³, μ = 1.228 mm^?1, R = 0.0351. The crystalline compound is ionic. The structural unit consists of [Ni(OH₂)₆]²⁺ and [TiF₆]^2? ions and Ur and H₂O molecules. The structural formula of the compound is [Ni(OH₂)₆][TiF₆](Ur)₂·H₂O. Hydrogen bonds in the compound are studied and analyzed.     

Structure of trans-diaqua-bis(3-hydroxybenzoylhydrazine)copper(II) sulfate monohydrate, [Cu(C7H8O2N2)2(OH2)2]SO4·H2O

Synthesis, X-ray phase analysis (XRPA), and IR spectroscopic study were performed to investigate the structure of [Cu(m-HBH)₂(OH₂)₂]SO₄·H₂O, where m-HBH = C₇H₈O₂N₂ (3-hydroxybenzoylhydrazine); a = 7.154(3) Å, b = 8.012(2) Å, c = 20.061(2) Å, β = 90.56(2)°; P2₁, Z = 2, R(F) = 0.046. The structure of the compound consists of the [Cu(m-HBH)₂(OH₂)₂]²⁺ complex cations, SO ₄ ^2? anions, and one water molecule. The copper atom is surrounded by a tetragonal bipyramid; c.n. is 6 = 4 + 2 (the distances are 2.030(5) Å, 2.054(6) Å, 2.061(5) Å, and 2.097(3) Å (equatorial); 2.459(4) Å and 2.53(4) Å (axial)). In complex compounds of 3d metals containing m-HBH, the function of the latter is probably invariable; the distribution of the anions and water molecules in the structure depends on the type of the metal and on the anion shape and geometry for metals with slightly different ionic radii.     

Structure of hexaaquamagnesium (II) bis(4-<Emphasis Type="Italic">p</Emphasis>-aminobenzenesulfamido-2,6-dimethoxypyrimidinate) pentahydrate

The X-ray analysis of a single crystal of Mg(C₁₂H₁₃N₄O₄S)₂·11H₂O, where (C₁₂H₁₃N₄O₄S)^? is the anion of 4-p-aminobenzenesulfamido-2,6-dimethoxypyrimidine (sulfadimethoxine) is carried out. Unit cell parameters are: a = 19.753(4) Å, b = 34.031(7) Å, c = 13.859(3) Å; β = 125.37(3)°, C2/c, Z = 8, R(F) = 0.042. The structure is built of [Mg(OH₂)₆]²⁺, (C₁₂H₁₃N₄O₄S)^?, and water molecules and corresponds to the formula [Mg(OH₂)₆](C₁₂H₁₃N₄O₄S)₂·5H₂O. The IR bands of ν_asymSO₂ and ν_symSO₂ are bathochromically shifted as a result of their participation in hydrogen bonding, and not because of any direct coordination of sulfadimethoxinate anion to the complexing atom through oxygen.     

X-ray study of M(Aet)2·8H2O (M = Sr, Ba) and the crystal structure of [Sr(Aet)(OH2)5](Aet)·3H2O

An X-ray phase and X-ray structural analysis of M(Aet)₂-8H₂O compounds, where M(II) = Sr and Ba; (Aet)^- = (C₁₀H₁₁N₄O₂S₂) is the sulfaethiodole (2-(para-aminobenzene-sulfamido)-5-ethyl-1,3,4-thiadiazole) anion is carried out. Symmetry and unit cell parameters of Sr(Aet)₂•8H₂O and Ba(Aet)₂-8H₂O are found: P2₁/c, Z= 4, a = 10.390(2) ?, b= 14.609(3) ?, c = 21.931(5) ?, β = 92.42(2)°, R = 0.041; and P2₁/c, Z= 4, a = 9.793(2) ?, b = 15.408(4) ?, c = 22.553(6) ?, β = 94.98(2)° respectively. The considered compounds are isostructural. The structure of Sr(Aet)₂-8H₂O is fully studied; the crystals of the compound are composed of the complex centrosymmetric dimeric [(H₂O)5Sr(Aet)₂Sr(OH₂)₅]²⁺ cations, (Aet)^- anions, and water molecules; the independent part of the structural formula of the compound is [Sr(Aet)(OH₂)₅](Aet)•3H₂O. The sulfaethiodole anion is coordinated to the complexing metal atom by oxygen and nitrogen atoms with the formation of a four-membered ring.     

X-Ray diffraction study of M(Aet)2·11H2O (M = Mn, Mg, and Mn0.5Mg0.5) and the crystal structure of [Mn(OH2)6](Aet)2·5H2O

X-ray phase and X-ray spectral analyses are performed for newly synthesized M(Aet)₂·11H₂O compounds, where M(II) = Mn, Mg, and Mg_0.5Mn_0.5, (Aet)⁻ = (C₁₀H₁₁N₄O₂S₂)⁻, the anion of ethazol (2-(paraaminobenzene sulfanilamide)-5-ethyl-1,3,4-thiadiazole). It is found that these compounds are isostructural. In the third compound, Mg and Mn statistically substitute for each other and the substitution takes place at any ratio of these metals. The structure of crystals of the [Mn(OH₂)₆](Aet)₂·5H₂O compound is studied: a = 17.160(2) ?, b = 14.115(1) ?, c = 15.130(2) ?, β = 98.23(3)°, P21/n, Z = 4, R(F) = 0.045. The compound consists of complex [Mn(OH₂)₆]²⁺ hexaaqua cations, (Aet)⁻ anions, and five water molecules. Original Russian Text Copyright ? 2009 by é. B. Miminoshvili, K. é. Miminoshvili, and L. A. Beridze __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 1, pp. 177–182, January–February, 2009.