L. Kh. Minacheva

Bis(citrato)germanate complexes with organic cations: Crystal structure of (HNic)2[Ge(HCit)2]·3H2O

Bis(citrato)germanate complexes with organic cations—protonated nicotinic acid ((HNic)2[Ge(HCit)2]·3H2O (I)), protonated nicotinamide ((HNad)2[Ge(HCit)2]·3H2O (II)), and protonated isonicotinic acid hydrazide ((HInd)2[Ge(HCit)2] (III)) (H4Cit is citric acid)—have been synthesized for the first time. Complexes I–III were studied by chemical and X-ray powder diffraction methods, thermal analysis, and IR spectroscopy. The X-ray diffraction study of complex I was carried out. The crystals are monoclinic, a = 10.931(7) Å, b = 11.420(1) Å, c = 23.188(6) Å, β = 101.54(4)°, V = 2836(2) Å3, z = 4, space group P21/n, R = 0.0334 for 1959 reflections with I > 2σ(I). In the complex anion [Ge(HCit)2]2− of the molecule of I, the coordination polyhedron of the Ge atom is a distorted octahedron formed by six O atoms of two tridentate chelating ligands HCit3− (Ge-O, 1.806–1.957 Å). In the structure of I, anions, cations, and water molecules are linked together by an intricate system of hydrogen bonds.

Bis(citrato)germanates of bivalent 3d metals (Fe, Co, Ni, Cu, Zn): Crystal and molecular structure of [Fe(H2O)6][Ge(HCit)2] · 4H2O

In continuation of a systematic study of bis(citrate)germanates, we synthesized a number of heterometallic germanium(IV) and 3d metal complexes based in citric acid (H4Cit) with the molecular formula [M(H2O)6][Ge(HCit)2] · nH2O, where M = Fe, n = 4 (I); Co, n = 2 (II); Ni, n = 2 (III); Cu, n = 1 (IV); Zn, n = 3 (V). The complexes were characterized by elemental analysis, X-ray diffraction, thermogravimetry, and IR spectroscopy. The X-ray diffraction analysis of compound I was performed. Crystals are monoclinic, a = 10.091(4) Å, b = 11.126(4) Å, c = 10.996(4) Å, β = 100.966(6)°, V = 1212.1(8) Å3, Z = 4, space group P21/n, R1 = 0.0561 for 2266 reflections with I > 2σ(I). Compound I is composed of centrosymmetric octahedral complexes-[Ge(HCit)2]2− anions and [Fe(H2O)6]2+ cations—and crystallization water molecules. Structural units in compound I are combined by a hydrogen bond system.

Synthesis, properties, and molecular and crystal structure of diantipyrylmethanium Bis(μ-tartrato)dihydroxydigermanate(IV) tetrahydrate (HDAm)2[Ge2(μ-L)2(OH)2] · 4H2O

AbstractThe complex (HDam)2[Ge2(μ-L)2(OH)2] · 4H2O (I) (H4L is tartaric acid, Dam is diantipyrylmethane) was synthesized for the first time. The individual character and composition of I was established by elemental analysis and X-ray diffraction. The thermal stability of I was studied. The coordination sites of H4L in the germanium complex were determined by IR spectroscopy. The structure of I was determined by X-ray crystallography. The crystals of I are triclinic: a = 9.3098(10) Å, b = 9.8088(10) Å, c = 17.6869(10) Å, α = 84.009(10)°, β = 77.926(10)°, γ = 67.088(5)°, V = 1454.3(2) Å3, Z = 2, space group P

Crystal and molecular structure of tetraaquabarium Di-μ-tartrato-di-μ-hydroxodigermanate(IV) pentahydrate [Ba(H2O)4][Ge2(μ-Tart)2(μ-OH)2] · 5H2O

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Synthesis, properties, and crystal structure of diphenylguanidinium bis(citrato)germanate hydrate (HDphg)2[Ge(HCit)2] · 1.08H2O

, R = 0.0628 for 6343 reflections with I > 2σ(I). The compound is composed of the complex anions [Ge2(μ-L)2(OH)2]2−, the HDam+ cations, and crystal water molecules. In the dimeric anion, the metal atoms are bound to two completely deprotonated ligands L4−. The latter are coordinated to the metal through the carboxyl (av. Ge-O, 1.911(6) Å) and hydroxyl (av. Ge-O, 1.768(6) Å) oxygen atoms. The coordination of each Ge atom is completed to trigonalbipyramidal by the O atom of the hydroxy ligand in the axial position (av. Ge-O, 1.748(7) Å). Both L4− ligands are D isomers. In the crystal, the complex anions and crystal water molecules are combined by a system of hydrogen bonds.

Synthesis, vibrational spectra, and crystal and molecular structure of 1,5-bis[2-(dihydroxyphosphinyl)phenoxy]-3-oxapentane dihydrate [(HO)2(O)P(C6H4)(OCH2CH2)2O(C6H4)P(O)(OH)2(H2O)] · H2O

The specific features revealed in the structure of germanium(IV) compounds with ligands in the form of anions of polybasic acids (monoamine, diamine, and triamine complexones, i.e., hydroxyethylidene-diphosphonic and carboxylic acids) have been considered. The influence of the individuality of specific acids on the structure type (mononuclear, binuclear, trinuclear, hexanuclear, polynuclear), the coordination mode of monodentate ligands and donor atoms of polydentate ligands (terminal, bridging, chelating, chelating-bridging), and variants of the coordination of polydentate ligands, i.e., anions of polybasic acids, with metal atoms (germanium, rare-earth elements, copper, barium), as well as on the dependence of the Ge-O bond length on the individual nature of ligands (OH, H2O, O(oxo)) and donor atoms of polydentate ligands α- and β-O(carb), O(hydr), O(P)] and their function in the structure (terminal, bridging, chelating, chelating-bridging), has been analyzed using 28 homometallic and heterometallic complexes as an example.

The conditions of formation of heterometallic complexes in the GeCl4 (SnCl4)-citric acid-M(CH3COO)2-H2O systems. The crystal and molecular structures of [M(H2O)6][Ge(HCit)2] · 4H2O (M = Mg, Mn, Co, Cu, Zn) and [M(H2O)6][Sn(HCit)2] · 4H2O (M = Mg, Co, Ni)

A new heteronuclear germanium barium complex with D-tartaric acid [Ba(H2O)4][Ge2(μ-Tart)2(μ-OH)2]·5H2O (I) (H4Tart is tartaric acid) was synthesized. The identity of compound I and its com- position were determined by elemental analysis and X-ray diffraction. The thermal stability of the compound was studied; the coordination centers of the ligand were found from IR spectroscopy. The structure of I was determined by X-ray crystallography. Crystals I are tetragonal: a = 8.5033(2) Å, c = 30.9393(11) Å, V = 2237.10(11) Å3, Z = 4, space group P41, R1 = 0.0301 based on 4215 reflections with I > 2σ(I). In crystals I, neutral [Ge2(μ-Tart)2] dimers are linked in pairs by double hydroxyl bridges to form {[Ge2(μ-Tart)2(μ-OH)2]2−}∞ polymeric chains. Hydrated Ba2+ cations and crystal water molecules are in between the anionic chains. Polymeric complex anions, hydrated barium cations, and H2O molecules are bound by a system of hydrogen bonds to form a framework.

Synthesis and characterization of heteronuclear germanium(IV) lanthanide 1,3-diamino-2-propanoltetraacetates: Crystal and molecular structure of the [Ge(OH)(μ-Hpdta)(μ-OH) Ln(H2O)3] · 2H2O complexes (Ln = Tb, Yb)

AbstractThe polymeric coordination compound {[Ge(μ-HCit)2Ba(H2O)3] · 3H2O}n (H4Cit = citric acid) was obtained for the first time for germanium(IV) citrates. The compound was characterized by elemental analysis, thermogravimetry, IR spectroscopy, and X-ray crystallography. Crystals of the compound are triclinic, a = 7.422(4) Å, b = 10.668(4) Å, c = 14.342(6) Å, α = 91.31(3)°, β = 95.81(4)°, γ = 104.08(4)°, V = 1094.5(8) Å3, Z = 2, space group P