X-ray mapping in heterocyclic design: XV. Tricyclic heterocycles based on 2-oxo-2,5,6,7-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-cyclopenta[<Emphasis Type="Italic">b</Emphasis>]pyridine-3-carbonitrile

The structures of five compounds are studied using single-crystal X-ray diffraction: 2-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[b]pyridine-3-carbonitrile [a = 15.641(8) Å, b = 9.373(5) Å, c = 7.387(4) Å, β = 92.91(5)°, Z = 4, space group P2₁/c]; 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-2,5,6,7-tetrahydro-1H-cyclopenta[b]pyridine-3-carbonitrile [a = 4.728(4) Å, b = 28.035(11) Å, c = 11.184(3) Å, Z = 4, space group P2₁2₁2₁]; 2-[2-(4-chlorophenyl)-2-oxoethoxy]-6,7-dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile [a = 10.1202(13) Å, b = 11.2484(18) Å, c = 13.4323(19) Å, β = 102.05(1)°, Z = 4, space group P2₁/c]; 2-(4-chlorophenyl)-3a, 6,7,8-tetrahydrocyclopenta[e][1.3]oxazolo[3.2-a]pyridine-4-carboxamide perchlorate [a = 7.702(2) Å, b = 9.599(3) Å, c = 23.798(5) Å, β = 93.44(2)°, Z = 4, space group P2₁/c]; and (3-amino-6,7-dihydro-5H-cyclopenta[b]furo[3.2-e]pyridin-2-yl)(4-chlorophenyl)methanone [a = 7.3273(2) Å, b = 13.390(3) Å, c = 28.792(8) Å, Z = 8, space group Pbca]. The structures are solved using direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0580, 0.0724, 0.0469, 0.0477, and 0.0418, respectively.     

X-ray mapping in heterocyclic design: XIV. Tricyclic heterocycles based on 2-Oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile

The structures of four compounds are studied using single-crystal X-ray diffraction: 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile [a = 4.908(4) Å, b = 11.644(10) Å, c = 13.587(2) Å, β = 94.31(5)°, Z = 2, space group P2₁]; 2-[2-(4-chlorophenyl)-2-oxoethoxy]-5,6,7,8-tetrahydroquinoline-3-carbonitrile [a = 7.6142(8) Å, b = 14.778(2) Å, c = 14.132(2) Å, β = 100.38(1)°, Z = 4, space group P2₁/c]; 4-(aminocarbonyl)-2-(chlorophenyl)-6,7,8,9-tetrahydro[1.3]oxazolo[3,2-a]quinolin-3-ium per-chlorate [a = 5.589(7) Å, b = 24.724(15) Å, c = 13.727(5) Å, β = 97.66(9)°, Z = 4, space group P2₁/n]; and (3-amino-5,6,7,8-tetrahydrofuro[2,3-b]quinolin-2-yl)-(4-chlorophenyl) methanone [a = 7.150(2) Å, b = 7.4288(10) Å, c = 15.314(3) Å, α = 98.030(10)°, β = 99.21(2)°, γ = 105.34(2)°, Z = 2, space group \(P\bar 1\)]. The structures are solved by direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0728, 0.0439, 0.1228, and 0.0541, respectively. The structure of 1-(4-chlorophenyl)-4-piperidin-1-yl-8,9-dihydro-7H-pyrrolo[3.2.1-ij]quinoline-5-carboxamide [a = 23.9895(9) Å, b = 5.1557(3) Å, c = 17.0959(9) Å, β = 106.43°, Z = 4, space group P ₁/c] is investigated by X-ray powder diffraction. This structure is solved using the grid search procedure and refined by the Rietveld method to R _wp = 0.0773, R _exp = 0.0540, R _p = 0.0585, R _b = 0.1107, and χ ² = 1.78.     

X-ray mapping in heterocyclic design: 16. X-ray diffraction study of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2<Emphasis Type="Italic">H</Emphasis>-cyclopenta[<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one

The structure of 1-(4-chlorophenacyl)-4-methyl-1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one is studied using single-crystal X-ray diffraction. The structure (a = 37.006(8) Å, b = 8.967(3) Å, c = 27.911(3) Å, β = 96.52(2)°, Z = 24, space group P2₁/c) is solved by direct methods and refined to R₁ = 0.0608 and wR₂ = 0.1170. Six crystallographically independent molecules differ in the dihedral angle between the phenyl and heterocycle planes. The formation of Cl?Cl aggregates is discussed.     

Coordination dimers constructed from metal(II) halides and the organic ligand 1,2-dimethoxy- 4,5-bis(2-pyridylethynyl)benzene

A series of new coordination compounds has been synthesized using the organic ligand 1,2-dimethoxy-4,5-bis(2-pyridylethynyl)benzene (dmpeb). The compounds all form dimers consisting of two metal cations bridged by two ligand molecules. Charge balance is provided by halide ligands, and the four-coordinate metal centers are distorted from the ideal tetrahedral environment. [CoCl₂(dmpeb)]₂ (1) crystallizes in the monoclinic space group P2₁/n with a = 8.5272(6) Å, b = 18.3653(13) Å, c = 13.3493(9) Å, β = 103.574(2)^°, V = 2032.2(2) ų, Z = 2. [ZnCl₂(dmpeb)]₂ (2) is isostructural to 1 and has the cell parameters a = 8.5495(4) Å, b = 18.4049(8) Å, c = 13.3692(6) Å, β = 103.4460(10)^°, V = 2046.01(16) ų, Z = 2. [ZnBr₂(dmpeb)]₂ (3) is also isostructural to 1 with a = 8.7882(5) Å, b = 18.7260(12) Å, c = 13.3857(8) Å, β = 102.5990(10)^°, V = 2149.8(2) ų, Z = 2. Additionally, the compounds [ZnI₂(dmpeb)]₂ (4, cell parameters: a = 8.9650(5) Å, b = 19.1251(10) Å, c = 13.4160(7) Å, β = 101.1660(10)^°, V = 2256.7(2) ų, Z = 2), [HgCl₂(dmpeb)]₂ (5, cell parameters: a = 8.8457(7) Å, b = 18.4030(15) Å, c = 13.3711(11) Å, β = 104.246(2)^°, V = 2109.7(3) ų, Z = 2), and [HgBr₂(dmpeb)]₂ (6, cell parameters: a = 9.0576(5) Å, b = 18.8634(11) Å, c = 13.4535(8) Å, β = 102.9780(10)^°, V = 2239.9(2) ų, Z = 2) are also isostructural to 1. A seventh dimeric compound, [HgI₂(dmpeb)]₂, not isostructural to the others was also characterized by X-ray crystallography. [HgI₂(dmpeb)]₂ (7) crystallizes in the triclinic space group P-1 with a = 8.8028(5) Å, b = 12.0990(7) Å, c = 12.4082(7) Å, α = 109.7240(10)^°, β = 107.3680(10)^°, γ = 93.0880(10)^°, V = 1169.57(12) ų, Z = 1.     

X-ray mapping in heterocyclic design: VI. X-ray diffraction study of 3-(isonicotinoyl)-2-oxooxazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]pyridine and the product of its hydrolysis

The structure of 3-(isonicotinoyl)-2-oxooxazolo[3,2-a]pyridine, C₁₃H₈N₂O₃, (I) is determined by X-ray powder diffraction analysis. Crystals I are orthorhombic, a = 16.610(2) Å, b = 3.853(1) Å, c = 16.431(2) Å, Z = 4, and space group Pna2₁. The structure is solved by the grid search procedure and refined by the Reitveld method (R_p = 0.086, R_wp = 0.115, R_e = 0.030, and χ² = 11.138). The structure of the product of hydrolysis of compound I, C₁₂H₁₀N₂O₂, (II) is determined by the single-crystal X-ray diffraction technique. Crystals II are orthorhombic, a = 8.755(4) Å, b = 10.526(17) Å, c = 23.088(6) Å, Z = 8, and space group Pc2₁b. The structure is solved by the direct method and refined by the full-matrix least-squares procedure to R = 0.0464. A fragment of two fused heterocycles in I is planar. The dihedral angle between the plane of the pyridine ring in the isonicotinoyl fragment and the plane of the bicyclic system is 51.2(2)°. Both exocyclic CO groups that are adjacent to the five-membered fragment contain double bonds. The structures of two crystallographically independent molecules II are almost identical to each other, and the isonicotinoyl fragment is nearly perpendicular to the plane of the pyridone fragment [84.3(1)° and 87.0(1)°].     

Crystal and molecular structures of dimethyl 4-phenylthiosemicarbazidediacetate and its adduct with rhodium(II) acetate

The crystal structures of dimethyl 4-phenylthiosemicarbazidediacetate C₁₃H₁₇N₃O₄S (I) and its adduct [C₈H₁₂O₈Rh₂ (C₁₃H₁₇N₃O₄S)₂] (II) with rhodium(II) acetate are determined by X-ray diffraction analysis. The unit cell parameters of crystals I are as follows: a = 8.066(6) Å, b = 15.812(6) Å, c = 24.977(8) Å, β = 94.88(3)°, space group P2₁/n, and Z = 8. The unit cell parameters of crystals II are a = 8.513(1) Å, b = 16.055(1) Å, c = 16.071(3) Å, β = 104.99(1)°, space group P2₁/c, and Z = 2. In structure I, two crystallographically independent molecules considerably differ from each other in the mutual orientation of the structural fragments containing the ester groups. In the centrosymmetric dimeric complex II, the organic molecule I acts as a monodentate thio ligand and adopts only one conformation.     

Synthesis and characterization of 9-(4-nitrophenyl)3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione and its methoxyphenyl derivative

9-(4-Nitrophenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione (NTHA) crystallizes in orthorhombic space group P2₁2₁2₁ with a = 5.9716(1) Å, b = 18.0476(3) Å, c = 19.2445(2) Å, V = 2074.04(5) ų, Z = 4, D_cal = 1.263 Mg m^?3 and R = 0.0521 (wR = 0.1326) for 4078 observed reflections. 9-(4-Nitrophenyl)-10-(4-methoxyphenyl)-3,3,6,6-tetramethyl-3,4,6,7,9,10-hexahydro-1,8(2H,5H) acridinedione NMTHA, crystallizes in monoclinic space group P2₁/c with a = 15.669(5) Å, b = 10.652(4) Å, c = 18.337(6) Å, β = 108.25(1)^°, V = 2906.66(2) ų, Z = 4, D_cal = 1.245 Mg m^?3 and R = 0.0725 (wR = 0.1847) for 5105 observed reflections. The experimental values are compared with the theoretical values calculated based on the semiemperical methods. The structures are stabilized by N–H?sO and C–H?sO types of intermolecular interactions in addition to van der Waals forces.     

Molecular structures of chalcone podands: A prognosis of photoinduced transformations in the crystals

A series of chalcone podands with the propenone group in the ortho position of the bridging aryl substituent with respect to the oxyethylene fragment is synthesized. The influence of the preorganization of the chalcone podand molecules in crystals on their ability to participate in topochemical reactions is investigated. From analyzing the X-ray structural data, the highest probability of the solid-state photochemical [2 + 2]cycloaddition is predicted for podands with phenyl substituents and the oxyethylene fragment containing two or three oxygen atoms. The X-ray structural data for the chalcone podand C₃₂H₂₆O₄ (3a) are as follows: a = 7.904(9) Å, b = 14.92(2) Å, c = 21.30(3) Å, β = 91.7(1)°, monoclinic system, space group P2₁/c, Z = 4, V = 2510(5) ų, ρ = 1.26 g/cm³, and R = 0.046; C₃₄H₃₀O₅ (3b): a = 15.738(9) Å, b = 11.889(2) Å, c = 15.0830(15) Å, β = 105.47(14)°, monoclinic system, space group C2/c, Z = 4, V = 2720.0(9) ų, ρ = 1.266 g/cm³, and R = 0.0418; C₃₂H₂₄N₂O₈ (4a): a = 17.9416(18) Å, b = 10.9703(8) Å, c = 41.699(2) Å, β = 105.970(11)°, monoclinic system, space group P2₁/c, Z = 4, V = 2781.4(5) ų, ρ = 1.348 g/cm³, and R = 0.0426; C₃₆H₃₂N₂O₁₀ (4c): a = 7.6286(5)Å, b = 17.9398(10) Å, c = 11.5890(3)Å, β = 95.287(4)°, monoclinic system, space group P2₁/n, Z = 2, V = 1579.27(14) ų, ρ = 1.372 g/cm³, and R = 0.0377; and C₂₈H₂₂O₆ (5a): a = 15.6032(10) Å, b = 8.1131(5) Å, c = 17.7334(11) Å, β = 91.381(5)°, monoclinic system, space group C2/c, Z = 4, V = 2244.2(2) ų, ρ = 1.345 g/cm³, and R = 0.0309.     

Crystal chemistry of elpidite from Khan Bogdo (Mongolia) and its K- and Rb-exchanged forms

Elpidite Na₂ZrSi₆O₁₅ · 3H₂O [space group Pbcm, a = 7.1312(12), b = 14.6853(12), and c = 14.6349(15) Å] from Khan Bogdo (Mongolia) and its K- and Rb-exchanged forms K_1.78Na_0.16H_0.06ZrSi₆O₁₅ · 0.85H₂O [Cmce, a = 14.054(3), b = 14.308(3), and c = 14.553(3) Å] and Na_1.58Rb_0.2H_0.22ZrSi₆O₁₅ · 2.69H₂O [Pbcm, a = 7.1280(10), b = 14.644(3), and c = 14.642(3) Å] that were obtained by cation exchange at 90°C, as well as K_1.84Na_0.11H_0.05ZrSi₆O₁₅ · 0.91H₂O [Cmce, a = 14.037(3), b = 14.226(3), and c = 14.552(3) Å] and Rb_1.78Na_0.06H_0.16ZrSi₆O₁₅ · 0.90H₂O [Cmce, a = 14.2999(12), b = 14.4408(15), and c = 14.7690(12) Å], obtained at 150°C are studied by single-crystal X-ray diffraction and IR spectroscopy. The base of the structures is a heteropolyhedral Zr-Si-O framework whose cavities accommodate Na (K, Rb) cations and H₂O molecules.     

X-ray mapping in heterocyclic design: X. X-ray diffraction study of 4-methyl-6,7,8,9-tetrahydro-2-quinolone

The structure of 4-methyl-6,7,8,9-tetrahydro-2-quinolone is studied by the single-crystal X-ray diffraction technique (a = 6.6890(17) Å, b = 7.926(2) Å, c = 8.993(3) Å, α = 85.50(2)°, β = 68.22(2)°, γ = 82.89(2)°, Z = 2, and space group \(\bar P1\)). The structure is solved by direct methods and refined to R₁ = 0.0592 and wR₂ = 0.1206. In the crystal, intermolecular hydrogen bonds link molecules into centrosymmetric dimers.     

Crystal structures of complexes of the <Emphasis Type="Italic">cys-syn-cys</Emphasis> isomer of dicyclohexano-18-crown-6 with oxonium hexafluorotantalate and oxonium hexafluoroniobate

The crystal structures of [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][TaF₆] and [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][NbF₆] complex compounds are determined using X-ray diffraction analysis. The tantalum complex has two polymorphic modifications, namely, the monoclinic (I) and triclinic (II) modifications. The unit cell parameters of these compounds are as follows: a = 8.507(4) Å, b = 11.947(5) Å, c = 27.392(12) Å, β = 93.11(1)°, Z = 4, and space group P2₁/n for modification I; and a = 10.828(1) Å, b = 11.204(1) Å, c = 12.378(1) Å, α = 72.12(1)°, β = 79.40(1)°, γ = 73.70(1)°, Z = 2, and space group P-1 for modification II. The triclinic niobium complex [(cys-syn-cys-dicyclohexano-18-crown-6 · H₃O)][NbF₆] (III) with the unit cell parameters a = 10.796(3) Å, b = 11.183(3) Å, c = 12.352(3) Å, α = 72.364(5)°, β = 79.577(5)°, γ = 73.773(4)°, Z = 2, and space group P-1 is isostructural with tantalum complex II. The structures of all three complexes are ionic in character. The oxonium cation in complexes I–III is encapsulated by the crown ether and thus forms one ordinary and two bifurcated hydrogen bonds with the oxygen atoms of the crown ether. This macrocyclic cation is bound to the anions through the C-H...F contacts (H...F, 2.48–2.58 Å). The conformation of the macrocycle in complex I differs substantially from that in complex II (III).     

Synthesis,thermal analysis,and crystal structure of manganese(II) 9-molybdocobaltate(III)

Manganese(II) 9-molybdocobaltate(III) of the composition [Mn(H₂O)₄] · [CoMo₉O₂₇(OH)₅] · 7H₂O (I) has been synthesized for the first time and investigated using X-ray diffraction and thermal gravimetric analyses. Compound I crystallizes in the trigonal system with the following unit cell parameters: a = 15.926(1) Å, c = 12.363(1) Å, V = 2715.6(4) ų, M = 1692.55, Z = 3, ρ_(calcd) = 3.105 g/cm³, space group R32.     

Crystal structure of tris(methylcyclopentadienyl) tetrahydrofuranatosamarium

The first crystal structure of tris(methylcyclopentadienyl) tetrahydrofuranato (THF) lanthanide complexes, (CH₃Cp)₃Sm · THF, is determined. The complex crystallizes from mixed solvents of tetrahydrofuran and hexane as a monomer in the orthorhombic space group Pc2₁n with the unit cell parameters a = 9.135(2) Å, b = 13.263(2) Å, c = 16.176(3) Å, and Z = 4.     

Crystal structures of dioxonium hexafluorotantalate and dioxonium hexafluoroniobate complexes with tetrabenzo-30-crown-10

Two isostructural complexes of dioxonium [H₅O₂]⁺ with tetrabenzo-30-crown-10 of the compositions [(tetrabenzo-30-crown-10 · H₅O₂)][TaF₆] (I) and [(tetrabenzo-30-crown-10 · H₅O₂)][NbF₆] (II) are studied using X-ray diffraction. The complexes crystallize in the monoclinic crystal system (space group C2/c, Z = 4). The unit cell parameters of these compounds are as follows: a = 15.6583(12) Å, b = 15.2259(13) Å, c = 16.4473(13) Å, and β = 99.398(6)° for complex I and a = 15.7117(12) Å, b = 15.2785(15) Å, c = 16.5247(15) Å, and β = 99.398(7)° for complex II. These complexes belong to the ionic type. The dioxonium cation [H₅O₂]⁺ in the form of the two-unit cluster [H₃O · H₂O]⁺ is stabilized by the strong hydrogen bond OH?O [O?O, 2.353(4) Å] and encapsulated by the crown ether. Each oxygen atom of the dioxonium cation also forms two oxygen bonds O?O(crown). The crown ether adopts an unusual two-level (pocket-like) conformation, which provides a complete encapsulation of the oxonium associate. The interaction of the cationic complex with the anion in the crystal occurs through contacts of the C-H?F type.     

Synthesis and crystal structure of a two-dimensional silver(I)-hexamethylenetetramine coordination polymer (<Emphasis Type="Italic">hmt</Emphasis>)

A novel two-dimensional coordination polymer [Ag(μ₃-hexamethylenetetramine)(H₂O)](BF₄) was synthesized and characterized by X-ray crystallography. It crystallized in the orthorhombic space group Pnnm with a = 15.561(7) Å, b = 10.754(5) Å, c = 6.514(3) Å, and Z = 4. Each Ag center is four-coordinated in a slightly distorted tetrahedral geometry. The structure consists of 2D wavy layers of hexagonal units; these 2D layers are further connected to form a 3D network by O-H⋯F, C-H⋯F hydrogen bonds with counter anions BF ₄ ⁻ in the layers. From Kristallografiya, Vol. 50, No. 4, 2005, pp. 648–650. Original English Text Copyright ? 2005 by Kong, Zhang, Sun, Okamura, Ueyama. The text was submitted by the authors in English.     

Refinement of the crystal structure of Zn-containing greifensteinite

The crystal structure of Zn-containing greifensteinite from the Pirineus Mine (Minas Gerais, Brazil) was refined (R = 0.045, 562 reflections with |F| > 2σ(F)). The unit-cell parameters are a = 15.941(3) Å, b = 11.877(3) Å, c = 6.625(2) Å, β = 95.09(2)°; V = 1249.4 ų; sp. gr. C2/c; and Z = 2. The idealized formula is [Mn(Fe²⁺, Zn)₄]Ca₂Be₄(PO₄)₆(OH)₄ · 6H₂O. The mineral is isostructural with the previously studied monoclinic representatives of the roscherite group from different deposits and differs from these representatives in that it contains Zn in one of two octahedral positions.     

Catenated molecular pattern in the crystal structure of a copper(II) complex with pyrazine-2,6-dicarboxylic acid and chloride ligands

The crystals of catena-dichloro-(dihydrogen pyrazine-2,6-dicarboxylato-O,O′,N,-N′) copper(II) dihydrate Cu[H₂(2,6-PZDC)]Cl₂?2H₂O are monclinic, space group C2/c with a = 11.658(2) Å, b = 6.778(1) Å, c = 16.390(3) Å, β = 98.90(3)^°, and Z = 4. Two adjacent copper(II) ions are bridged by a fully protonated pyrazine-2,6-dicarboxylic acid molecule which uses for bridging its O,O′,N-bonding moiety on one side and a single hetero-ring nitrogen atom on the other. Two chloride ions in axial position complete the octahedral coordination around the metal ions with bond distances: Cu–N 2.027(3) ÅA, Cu–N′ 2.005(3) ÅA, Cu–Cl. 2.281(1) ÅA, and Cu–O 2.446(2) ÅA. Copper(II) ions are located in the center of symmetry and are coplanar with the ligand acid molecule forming flat molecular chains propagating in the direction of the b axis. Hydrogen bonds via solvation water molecule link the chains into molecular layers parallel to the ac plane. Weak van der Waals type interactions operate between the layers.     

Complexes of Ambidentate N,O-Donor Ligands with Rhenium(I) and -(V)

The reaction of the potentially bidentate ambidentate N,O-donor ligands 3-hydroxy-2-pyridinecarboxylic acid (Hhpc) and 3-hydroxy-2-(hydroxymethyl)pyridine (Hhhp) with trans-[ReOCl₃(PPh₃)₂] led to the isolation of the products [ReOCl(hpc)₂] (1) (from acetonitrile) and [ReOCl₂(hhp)(PPh₃)] (2) (from ethanol) respectively. In both complexes hpc and hhp are coordinated as bidentate N,O-donor chelates, rather than as O,O-donor ligands. From the reaction of [Re(CO)₅Cl] and Hhhp·HCl in ethanol the neutral complex fac-[Re(CO)₃Cl(Hhhp)] (3) was obtained, with N,O-coordination of Hhhp. Complex 1 crystallizes in the monoclinic space group P2₁/n with a?=?6.8782(3), b?=?20.0647(8), c?=?10.8692(4) Å, β?=?107.545(1)°, and Z?=?4. Complex 2 crystallizes in the triclinic space group P-1 with a?=?7.3523(4), b?=?8.1047(5), c?=?19.591(1) Å, α?=?91.133(2)°, β?=?93.656(2)°, γ?=?93.074(2)° and Z?=?2. Complex 3 has monoclinic P2₁/c symmetry with the cell parameters a?=?10.6452(5), b?=?11.1372(5), c?=?9.7229(5) Å, β?=?106.107(2)°, and Z?=?4.

Graphical Abstract

The reaction of the potentially bidentate ambidentate N,O-donor ligands 3-hydroxy-2-pyridinecarboxylic acid (Hhpc) and 3-hydroxy-2-(hydroxymethyl)pyridine (Hhhp) with trans-[ReOCl₃(PPh₃)₂] led to the isolation of the products [ReOCl(hpc)₂] (from acetonitrile) and [ReOCl₂(hhp)(PPh₃)] (from ethanol) respectively. In both complexes hpc and hhp are coordinated as bidentate N,O-donor chelates, rather than as O,O-donor ligands. From the reaction of [Re(CO)₅Cl] and Hhhp·HCl in ethanol the neutral complex fac-[Re(CO)₃Cl(Hhhp)] was obtained, with N,O-coordination of Hhhp. Spectroscopic data and the X-ray crystal structures of the complexes are reported.

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Synthesis and structure of oxovanadium(IV) complexes [VO(<Emphasis Type="Italic">Acac</Emphasis>)<Subscript>2</Subscript>] and [VO(<Emphasis Type="Italic">Sal</Emphasis>: <Emphasis Type="Italic">L</Emphasis>-alanine)(H<Subscript>2</Subscript>O)]

Bis(acetylacetonato)oxovanadium C₁₀H₁₄O₅V (I) and (S)-[2-(N-salicylidene)aminopropionate]oxovanadium monohydrate C₁₀H₉NO₅V (II) are synthesized. The crystal structures of compounds I and II are determined using single-crystal X-ray diffraction. Crystals of compound I are triclinic, a = 7.4997(19) Å, b = 8.2015(15) Å, c = 11.339(3) Å, α = 91.37(2)°, β = 110.36(2)°, γ = 113.33(2)°, Z = 2, and space group \(P\bar 1\). Crystals of compound II are monoclinic, a = 8.5106(16) Å, b = 7.373(2) Å, c = 9.1941(16) Å, β = 101.88(1)°, Z = 2, and space group P2₁. The structures of compounds I and II are solved by direct methods and refined to R₁ = 0.0382 and 0.0386, respectively. The oxovanadium complexes synthesized are investigated by vibrational spectroscopy.     

Synthesis and structure of the [Os<Emphasis Type="Italic">Thio</Emphasis><Subscript>6</Subscript>]Br<Subscript>3</Subscript> · H<Subscript>2</Subscript>O complex

A complex of the composition [OsThio ₆]Br₃ · H₂O is synthesized by the reaction of H₂OsBr₆ with thiourea in a 0.5 M HBr solution. The [OsThio ₆]Br₃ · H₂O complex is characterized using electronic absorption and infrared spectroscopy. The structure of the complex is determined by X-ray diffraction analysis. The crystals are orthorhombic with the unit cell parameters a = 20.510(4) Å, b = 11.186(2) Å, c = 11.892(2) Å, space group Pccn, and Z = 4. The thiourea molecules are coordinated to the osmium atom through the sulfur atom. The osmium atom has an octahedral coordination. The Os-S distances fall in the range 2.39–2.40 Å. The outersphere H₂O molecules and Br^? anions are involved in hydrogen bonds with the NH₂ groups of the thiourea molecules.