Base-Stabilized Monomeric Stibinoalane dmap–Al(Et<Subscript>2</Subscript>)Sb(<Superscript>t</Superscript>Bu)<Subscript>2</Subscript>

Abstract  

The six-membered heterocycle [Me₂AlSb(t-Bu)₂]₃ was reacted with the strong Lewis-base 4-dimethylaminopyridine (dmap), yielding the first completely alkyl-substituted monomeric complex dmap–Al(Me₂)Sb(t-Bu)₂ 1. 1 was characterized by NMR spectroscopy and single crystal X-ray diffraction. 1 is monoclinic, space group P2 ₁ /n with a = 9.9004(2) ?, b = 16.8166(3) ?, c = 13.8400(3) ?, β = 100.746(1)° and Z = 4.     

Crystal structure of Sr(AsUO<Superscript>6</Superscript>)<Subscript>2</Subscript> · 8H<Subscript>2</Subscript>O

The crystal structure of the compound Sr(AsUO₆)₂ · 8H₂O is determined by X-ray diffraction analysis (monoclinic system, sp. gr. Pc, unit-cell parameters a = 7.154(1) Å, b = 7.101(1) Å, c = 18.901(7) Å, β = 92.67(2)°, Z = 2). The structure is built by (001)-parallel [AsUO₆]^? layers formed by flattened square UO₆ bipyramids and AsO₄ tetrahedra. The neighboring layers are connected via SrO₈ square antiprisms. The cavities of the polyhedral framework thus formed are occupied by H₂O molecules. The displacements of the anion complexes by a half-translation with respect to one another along only one lattice period is a characteristic feature of this polymorphous modification of the uran-mica group.     

Molecular structure of [(tBu)2Al(μ-OPh)]2

The molecular structure of [(^tBu)₂Al(-OPh)]₂ has been determined. The intramolecular steric interaction between the phenyl groups and thetert-butyl ligands results in the geometry about aluminum being significantly distorted from tetrahedral, with the AlC₂ planes are pitched 62° with respect to the Al₂O₂ plane. The greater distortion from tetrahedral about aluminum, and the orientation of the phenoxide ring more nearly perpendicular to the M₂O₂ core as compared to that in [(^tBu)₂Ga(-OPh)]₂ are all consistent with increased^tBu...Ph steric interaction as a consequence of the smaller M₂O₂ core for [(^tBu)₂Al(-OPh)]₂. Crystal data: tetragonal, I4₁/acd,a=16.44(1),c=21.41(1) Å,V=5788(7) ų,Z=8,R=0.047,R _w=0.045.     

Molecular structure of [(tBu)2Al(μ-Cl)]2

The crystal and molecular structure of [(^tBu)₂Al(μ-Cl)]₂ has been determined. The bond lengths and geometry about aluminum are similar to that in [Me₂Al(μ-Cl)]₂ and [(Mes)₂Al(μ-Cl)]₂ suggesting that the geometry about the aluminum is defined by the steric repulsion between the alkyl groups on adjacent aluminum centers and not steric congestion between ligands on individual aluminum centers. Crystal data: Triclinic, $P\bar 1$ ,a=6.514(1),b=8.628(2),c-11.236(2)c=11.236(2) Å, α=102.05(3), β=105.32(3), γ=103.47(3)°,V=567.2(3) ų,Z=1,R=0.063,R _w =0.067.     

Molecular structure of [(tBu)2Al(μ-NHtBu)]2

The crystal and molecular structure of [(^tBu)₂Al(-NH^tBu)]₂ has been determined. The unit cell contains two independent molecules with only slight variation in the orientation of thetert-butyl ligands. Crystal data: Triclinic, ,a=9.0138(6),b=10.2944(8),c=15.791(1) , =91.262(6), =89.822(6), =106.141(6)°,V=1407.2(2) ų,Z=2,R=0.039,R _w=0.041.     

Triosmium and triruthenium clusters containing morpholine ligand: X-ray structure of Os<Subscript>3</Subscript>(CO)<Subscript>10</Subscript>(μ-η<Superscript>2</Superscript>-NC<Subscript>4</Subscript>H<Subscript>6</Subscript>O)(μ-H)

Treatment of the labile cluster Os₃(CO)₁₀(CH₃CN)₂ with morpholine in benzene at 60^°C afforded Os₃(CO)₁₀(μ-η²-NC₄H₆O)(μ-H) (1). Decarbonylation of 1 at 128^°C gave Os₃(CO)₉(μ₃-η²-NC₄H₆O)(μ-H) (2), which reacts with PPh₃ at ambient temperature to give an addition product Os₃(CO)₉(μ-η²-NC₄H₆O)(PPh₃)(μ-H) (3). Compound 1 reacted with PPh₃ at 98^°C to give the substitution product 4 which is an isomer of 3. The reaction of Ru₃(CO)₁₂ with morpholine in the presence of Me₃NO in refluxing benzene at 80^°C afforded Ru₃(CO)₉(μ₃-η²-NC₄H₆O)(μ-H) (5). Compounds 1– 5 have been characterized by elemental analysis, infrared, ¹H NMR, and mass spectroscopic data. The molecular structure of 1 has been determined by single crystal X-ray diffraction analysis. Compound 1 crystallizes in the monoclinic space group P2/c with a = 29.598(8) Å, b = 9.202(2) Å, c = 14.496(4) Å, β = 93.19(3)^°, Z = 8, and V = 3942(2) ų. Compound 1 consists of an isosceles triangle of osmium atoms with one elongated Os–Os edge, which is bridged by the hydride and the morpholine ligand.     

Synthesis and crystal structure of [(C<Subscript>7</Subscript>H<Subscript>10</Subscript>N)<Subscript>2</Subscript>]<Superscript>2+</Superscript> [Sb<Subscript>2</Subscript>Cl<Subscript>8</Subscript>]<Superscript>2−1</Superscript>

The reaction of 2,6-dimethylpyridine with SbCl₃ and HCl affords the title compound, the structure of which is ascertained by X-ray diffraction. The unit cell consists of one bridged Sb₂Cl₈²⁻ anion and two 2,6-dimethylpyridinium cations. The trivalent antimony ion is bonded not only directly to chlorine anions, but also is coordinated with chlorine anions by secondary bonds. In the crystal, there exists infinite coordinated chains of [Sb₂Cl₈] _n ²ⁿ⁻ anions running along the a axis, which link 2,6-dimethylpyridinium cations by N-H…Cl hydrogen bonds.     

Synthesis and crystal structure of binuclear molecule Ho<Subscript>2</Subscript>(2-FC<Subscript>6</Subscript>H<Subscript>4</Subscript>COO)<Subscript>6</Subscript>⋅4H<Subscript>2</Subscript>O

The complex Ho₂(2-FC₆H₄COO)₆?4H₂O has been synthesized and structurally characterized by single crystal X-ray diffraction methods. The complex crystallizes in the triclinic system with space group P \(\bar 1\), lattice parameters a = 9.293(8) Å, b = 9.845(8) Å, c = 12.703(11) Å, α = 85.470(14)^°, β = 87.537(12)^°, γ = 62.485(11)^°, V = 1027.5(15) ų, Z = 1, D_calc = 1.998 Mg/m³. The Ho³⁺ ion is in distorted monocapped square-antiprism coordination environment and is coordinated by nine oxygen atoms, seven from five 2-FC₆H₄COO^2? groups, two from two water molecules. Two Ho³⁺ ions are linked together by four bridging carboxylate groups to form a binuclear molecule with inversion center.     

Synthesis and structure of a new hybrid vanadium arsenate: [VO<Subscript>2</Subscript>(phen)]<Subscript>2</Subscript>(H<Subscript>2</Subscript>AsO<Subscript>4</Subscript>)⋅H<Subscript>3</Subscript>O

A new hybrid vanadium arsenate [VO₂(phen)]₂(H₂AsO₄)H₃O 1 (phen = 1,10-phenanthroline) was synthesized under hydrothermal reaction conditions and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis (TGA), IR and elemental analyses. Crystal data for 1: monoclinic, P2₁/n, a = 9.175(2) Å, b = 18.638(5) Å, c = 14.482(4) Å, = 102.333(3), V = 2419(1) ų, Z = 4. Compound 1 is composed of discrete tricyclic (VO₂)₂(H₂AsO₄) cluster decorated with two phen ligands. The discrete arsenic–vanadium clusters are extended into three-dimensional supramolecular arrays via – stacking interactions of phen groups.     

Nitrilotris(methylenephosphonato)potassium K[μ<Superscript>6</Superscript>-NH(CH<Subscript>2</Subscript>PO<Subscript>3</Subscript>)<Subscript>3</Subscript>H<Subscript>4</Subscript>]: Synthesis,structure, and the nature of the K–O chemical bond

The crystal structure of nitrilotris(methylenephosphonato)potassium K[μ⁶-NH(CH₂PO₃)₃H₄]—a three-dimensional coordination polymer—was determined. The potassium atom is coordinated by seven oxygen atoms belonging to the six nearest ligand molecules, resulting in distorted monocapped octahedral coordination geometry. The complex contains the four-membered chelate ring K–O–P–O. The K–O chemical bond is predominantly ionic. Meanwhile, the bonds of the potassium atom with some oxygen atoms have a noticeable covalent component. In addition to coordination bonds, the molecules in the crystal packing are linked by hydrogen bonds.     

Aquanitrilotris(methylenephosphonato)dirubidium [Rb<Subscript>2</Subscript>(H<Subscript>2</Subscript>O){μ<Superscript>12</Superscript>-NH(CH<Subscript>2</Subscript>PO<Subscript>3</Subscript>H)<Subscript>3</Subscript>}]: Synthesis and structure

Aquanitrilotris(methylenephosphonato)dirubidium is a 3D coordination polymer with a layer structure. Space group \(P\bar 1\), Z = 2; a = 8.0380(3) Å, b = 9.0522(4) Å, and c = 10.7837(4) Å; α = 113.252(4)°, β = 105.391(3)°, and γ = 96.182(3)°. Rb atoms populate two symmetrically inequivalent positions with c.n. = 8 and 10; significant difference in O–Rb–O angles in the coordination polyhedra is indicative of the ionic type of Rb–O bonds. In the crystal packing, molecules are connected by not only coordination bonds but hydrogen bonds as well.     

Synthesis and structure of [(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>CSSC(NH<Subscript>2</Subscript>)<Subscript>2</Subscript>]<Subscript>2</Subscript>[OsBr<Subscript>6</Subscript>]Br<Subscript>2</Subscript> · 3H<Subscript>2</Subscript>O

The complex [(NH₂)₂CSSC(NH₂)₂]₂[OsBr₆]Br₂ · 3H₂O is synthesized by the reaction of K₂OsBr₆ with thiocarbamide in concentrated HBr and characterized using electronic absorption and IR absorption spectroscopy. Its crystal structure is determined by X-ray diffraction. The crystals are orthorhombic, a = 11.730(2) Å, b = 14.052(3) Å, c = 16.994(3) Å, space group Cmcm, and Z = 4. The [OsBr₆]^2? anionic complex has an octahedral structure. The Os-Br distances fall in the range 2.483–2.490 Å. The α,α′-dithiobisformamidinium cation is a product of the oxidation of thiocarbamide. The S-S and C-S distances are 2.016 and 1.784 Å, respectively. The H₂O molecules, Br^?ions, and NH₂ groups of the cation are linked by hydrogen bonds.     

Synthesis and crystal structure of [UO<Subscript>2</Subscript>CrO<Subscript>4</Subscript>(C<Subscript>5</Subscript>NH<Subscript>5</Subscript>COO)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)]·2H<Subscript>2</Subscript>O

Crystals of UO₂CrO₄(C₅NH₅COO)₂(H₂O)] · 2H₂O are synthesized and their structure is studied by X-ray diffraction. The compound crystallizes in the triclinic crystal system. The unit cell parameters are as follows: a = 7.0834(10) Å, b = 10.6358(14) Å, c = 12.9539(17) Å, α = 75.096(2)°, β = 74.490(2)°, and γ = 80.657(2)°; V = 904.1(2) ų, space group P \(\bar 1\), Z = 2, and R = 0.026. The structure is built of [UO₂CrO₄(C₅NH₅COO)₂(H₂O)]₂ centrosymmetric dimers, which are linked into a framework by a system of hydrogen bonds involving inner-sphere and outer-sphere water molecules. The coordination number of the U(VI) atom is seven, and the coordination polyhedron is a pentagonal bipyramid with the oxygen atoms of the uranyl group, two chromate groups, two molecules of isonicotinic acid, and a water molecule at the vertices. The crystal chemical formula of the [UO₂CrO₄(C₅NH₅COO)₂(H₂O)]₂ dimer is represented as AB ² M ₃ ¹ , where AB ² M ₃ ¹ , where A = UO ₂ ²⁺ , B ² = CrO ₄ ^2? , and M ¹ = = C₅NH₄COOH and H₂O.     

Molecular Structure of [Me<Subscript>2</Subscript>Al(μ-OPh)]<Subscript>2</Subscript>: A Crystallographic and Ab initio Study

Abstract The molecular structure of [Me₂Al(μ-OPh)]₂ has been determined. The phenoxide ring is parallel to the Al₂O₂ ring rather than the energetically favored perpendicular configuration determined by ab initio calculations. Ab initio calculations successfully predict the structures of sterically demanding analogs. The adoption of the parallel configuration allows for an estimation of the magnitude of crystal packing forces. A discussion of the parameters controlling the structures of dialkylaluminum phenoxides is presented. Crystal data: group Pbca, a = 12.127(2), b = 8.491(2), c = 17.299(4) ?, V = 1781.3(6) ?³, Z = 4, R = 0.0695, wR ₂ = 0.1390. Graphical Abstract The molecular structure of [Me₂Al(μ-OPh)]₂ has been determined. The phenoxide ring is parallel to the Al₂O₂ ring rather than the energetically favored perpendicular configuration as determined by ab initio calculations.      

Anisotropy of microhardness and fracture of (NH<Subscript>4</Subscript>)<Subscript>2</Subscript>Ni(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> · 6H<Subscript>2</Subscript>O (ANSH) crystals

The Vickers hardness of the (010) and (001) planes in (NH₄)₂Ni(SO₄)₂ · 6H₂O (ANSH) crystals has been measured. Anisotropy hardness of the first kind is revealed for the (010) plane in ANSH. The hardness anisotropy coefficient k ₂ was determined to be 1.5. The temperature dependence of the microhardness of the (001) face of ANSH crystals was investigated in the temperature range from 20 to 80°C. The character of fracture of the (100), (010), and (001) planes during indentation with a spherical indenter has been qualitatively determined.     

Synthesis and Characterization of <Emphasis Type="Italic">Cis</Emphasis>-[V<Superscript>IV</Superscript>O(pzc)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)]·2H<Subscript>2</Subscript>O (pzc: 2-pyrazinecarboxylate)

Abstract  

Hydrothermal synthesis and the structural characterization of V(IV) complex of 2-pyrazinecarboxylate (pzc), is reported. The vanadium is in a distorted octahedral environment. Pairs of pyrazine-2-carboxylate ligands are always cis to each other. The pzc ligands do not link adjacent vanadium atom directly. The remainder of the three-dimensional network is completed by intense hydrogen bonding of uncoordinated water molecules to aqua and pzc ligands. Cis-[V^IVO(pzc)₂(H₂O)]·2H₂O, 1, was characterized by means of elemental analysis (CHNS), TGA, FT-IR, manganometric titration, bond valance sum calculations and single crystal X-ray diffraction methods. Crystal data for 1: monoclinic space group P2 ₁ /c and unit-cell parameters are a = 9.1142(5), b = 16.5822(10), c = 12.8936(7) ?, β = 131.625(3)° and Z = 4. To the best of our knowledge, cis-[V^IVO(pzc)₂(H₂O)] is reported without single crystal structure by Eugenio Garribba and his colleagues in year 2006. Herein we complete full characterization of the title complex with single crystal structure and also 1 will be the first reported example of solid vanadium complex of 2-pyrazinecarboxylates involving intense hydrogen bonding.     

Crystal growth and properties of Rb<Subscript>2</Subscript>Ni(SO<Subscript>4</Subscript>)<Subscript>2</Subscript> · 6H<Subscript>2</Subscript>O (RNSH)

Large single crystals of rubidium nickel hexahydrate Rb₂Ni(SO₄)₂ · 6H₂O (RNSH) of optical quality were grown for the first time. The atomic structure of RNSH crystals was refined. A comparative analysis of the crystal structures of (M ¹⁺)₂Ni(SO₄)₂ · 6H₂O, where M ¹⁺ is K, Rb, or Cs, was performed. The solubility curve of RNSH in water was measured. The optical and thermogravimetric properties of RNSH were investigated. The internal defect structure of RNSH crystals was studied by X-ray topography.     

Synthesis and crystal structure of [Zn(H<Subscript>2</Subscript>O)<Subscript>6</Subscript>]X<Subscript>2</Subscript> . 8H<Subscript>2</Subscript>O (X = 4′,7-dimethoxylisoflavone-3′-sulfonate)

A water soluble derivative of daidzein, [Zn(H₂O)₆] X₂ ⋅ 8H₂O (X = 4′,7-dimethoxylisoflavone-3′-sulfonate) was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. Zn(II) is located on an inversion centre and octahedrally coordinated by six water molecules. [Zn(H₂O)₆]²⁺, C₁₇H₁₃O₄SO₃⁻ and H₂O form many hydrogen bonds, which consist of the hydrophilic areas of title compound. The isoflavone skeletons arrange in an antiparallel fashion. They form the hydrophobic areas of title compound and π ⋅s π stacking interactions exist among them. The sulfo-group is an important bridge as a structural link between the hydrophilic region and the hydrophobic region. The hydrogen bonds, π ⋅ π stacking interactions exist in its crystal structure, which assemble the moieties into a three-dimensional networking structure.     

The crystal structure of calcium aqua{ethylenediaminetetraacetato(3-)}nickelate(II) tetrahydrate,Ca[Ni(H<Emphasis Type="Italic">Edta</Emphasis>)(H<Subscript>2</Subscript>O)]<Subscript>2</Subscript>·4H<Subscript>2</Subscript>O

The crystal structure of Ca[Ni(HEdta)(H₂O)]₂ · 4H₂O (HEdta ^3?is a protonated anion of ethylenediaminetetraacetic acid) is determined. The unit-cell parameters are as follows: a = 7.706(1), b = 14.923(9), and c = 26.570(5) Å; V = 3055.6(2.4) ų; Z = 8; and space group Pbcn. Crystals are shaped as tetragonal prisms and colored green, which is not characteristic of this class of compounds. The structure is built of Ca²⁺ cations, octahedral [Ni(HEdta)(H₂O)]^? complex anions, and crystallization water molecules. In the complex anion, one of the acetate branches is free of coordination, whereas the remaining three branches coordinate the central atom forming glycinate metallocycles. The structure is based on sandwich layers, which are formed by networks of flat tetragonal Ca[Ni(HEdta)(H₂O)]₄(H₂O)₂ fragments adjoining one another by vertices.     

Solvothermal Syntheses and Crystal Structures of Two Thiostannates(IV) [M(tepa)]<Subscript>2</Subscript>(<Emphasis Type="Italic">μ</Emphasis>-Sn<Subscript>2</Subscript>S<Subscript>6</Subscript>) (M = Fe<Superscript>2+</Superscript> and Co<Superscript>2+</Superscript>)

Abstract  

Two new thiostannates [M(tepa)]₂(μ-Sn₂S₆) (tepa = tetraethylenepentamine, M = Fe²⁺ 1 and Co²⁺ 2) were prepared by solvothermal method. Compounds 1 and 2 are isostructural. Both the compounds crystallize in the tetragonal system, space group I41/a (no. 88) with the crystal parameters of 1: a = 25.683(2) ?, b = 25.683(2) ?, c = 9.9860(9) ?, V = 6,586.7(11) ?³, Z = 8, and 2: a = 25.742(3) ?, b = 25.742(3) ?, c = 9.8977(12) ?, V = 6,558.5(14) ?³, Z = 8. The Sn₂S₆ ⁴⁻ anion acts as a bidentate bridging ligand connecting two transition metal complex cations by trans terminal S atoms to form neutral centrosymmetric [M(tepa)]₂(μ-Sn₂S₆) moieties.