V. S. Sergienko

Structural chemistry of peroxo compounds of group VI transition metals: II. Peroxo complexes of molybdenum and tungsten: A review

The specific features revealed in the structure of the molybdenum and tungsten peroxo complexes with the ratios M: O2 = 1: 1, 1: 2, and 1: 4 are considered. It is demonstrated that the geometry of the coordination polyhedron of the metal atom is primarily determined by the “metal: peroxo ligand” ratio. Formally, the pentagonal bipyramidal coordination polyhedra of the Mo(VI) and W(VI) oxo monoperoxo and oxo diperoxo complexes (the coordination numbers of the metal atoms are equal to seven) have different geometries, namely, the MO(O2)A4 pseudooctahedral and MO(O2)2A2 pseudotrigonal bipyramidal configurations.

Structural chemistry of oxoperoxo complexes of vanadium(V): A review

This paper presents a review of the structural features of monomeric, dimeric, and polymeric oxoperoxo complexes of vanadium(V). The structural manifestations of the trans effect of multiply bonded oxo and peroxo ligands in pseudooctahedral oxo monoperoxo complexes of vanadium(V) are compared. The dependence of the geometric parameters of the structural fragment V(O2)n (n = 1, 2) (V-O, O-O bond lengths; OVO angles) on the type of coordination seven-vertex polyhedron (pseudooctahedron, n = 1; pseudotrigonal bipyramid, n = 2) of the metal atom is analyzed. Regular distortions of the coordination polyhedra of vanadium atoms (pseudooctahedron, pseudotrigonal bipyramid, pseudotetragonal pyramid, pseudotetrahedron) are considered.

Triple Insertion of Ethylisocyanate into A W-Cl Bond and its Inner-Sphere Cyclization. Crystal Structure of Tetrachlorooxo (3,5-Diethyl- 2-Methylamino[1,3,5]-Oxadiazine- 2,4-Dione)Tungsten(VI)

The insertion product [WCl5{N(Et)C(O)OC(NEt)N(Et)C(O)Cl}] (I) is obtained by the room-temperature reaction of WCl6 with an excess of EtNCO in dichloroethane. The structure of the chain ligand in I is deduced from an IR study and the results of X-ray diffraction analyses of crystals of an oxo-complex, WOCI4{OCN(Et)C(O)N(Et)C(NHEt)O} (II), which is obtained by partial hydrolysis of I.

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.

Structural Chemistry of 1-Hydroxyethylidenediphosphonic Acid Complexes

The structural features of complexes of 1-hydroxyethylidenediphosphonic acid (HEDP) with different metals (geometric isomerism, dentate numbers and the mode of coordination of organophosphorus ligand, the structural type and degree of oligomerization, regular distortions of the coordination polyhedron, and the mutual influence of the ligands) are considered. The dependences of the complex structures and of the degree of deprotonation of the HEDP ligands on the synthesis conditions (solution pH and metal : HEDP ratio), on the nature of the metal and the outer-sphere cation, on the composition of the hydrate sphere, and on the availability of the accompanying ligands are also established.

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

Structural features of monomeric octahedral d 2 rhenium(V) oxo complexes: The structure of d 2 rhenium(V) monooxo compounds with sulfur and hydrogen atoms trans to the O(oxo) ligands

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