2,6-Di(1H-tetrazol-1-yl)pyridine and its cupric chloride complex

2,6-Di(1H-tetrazol-1-yl)pyridine (DTP) was prepared by a four-stage procedure, including step-by-step heterocyclization of both amino groups of 2,6-diaminopyridine with triethyl orthoformate and sodium azide. According to quantum-chemical calculations and single crystal X-ray diffraction data, DTP crystallizes in the form of the thermodynamically most stable conformer and has an almost flat molecular geometry. DTP was found to react with CuCl₂ ⋅ 2H₂O in ethanol to give the [Cu(DTP)Cl₂(H₂O)]_n complex, which is a 1D coordination polymer, formed at the expense of bridging DTP ligand via the tetrazole ring nitrogen atoms N⁴. Possible coordination cites in DTP molecule are discussed using the data of quantum chemical calculations. The pyridine ring nitrogen atom of DTP does not participate in the formation of either coordination or intermolecular hydrogen bonds. This is explained by the results of quantum chemical calculations showing that this atom is less basic than N3 and N4 atoms of DTP molecule.     

Synthesis and X-ray crystal structure of cis-dichloro(cyclopentylamine) (dimethyl sulphoxide)platinum(II)

Summary cis-Dichlorocyclopentylamine(dimethyl sulphoxide)-platinum(II) is obtained, in addition to small quantities of the corresponding trans compound, by reaction of K₂PtCl₄ with cyclopentylamine in DMSO solution, where it is formed as the thermodynamically favoured isomer. An X-ray crystal structure analysis confirms the cis configuration. Coordination around the metal centre is square planar, and the ligand bond angles at the Pt atom are close to the expected values of 90 and 180°. The DMSO ligand is S-coordinated to Pt. The Pt-Cl bond lengths, 2.299(2) and 2.317(2) Å, are normal for structures of this type, as are the Pt-N and Pt-S bond distances, 2.059(5) and 2.191(2) Å, respectively.Author to whom all correspondence should be directed.     

Crystal structure of Bis(<Emphasis Type="Italic">N</Emphasis>-benzyl)salicylideneiminatocobalt(II)

Crystal structure of Co^IIL₂ complex (where L is (N-benzyl)salicylideneiminate ion) is determined by X-ray diffraction analysis. In this mononuclear molecular complex (with C₂ symmetry), the Co atom has a distorted tetrahedral coordination to two O atoms and two N atoms of two bidentate chelate ligands L (Co-O 1.919(2) Å and Co-N 2.009(2) Å; angles OCoO(A) 113.17(7)°, NCoN(A) 125.44(7)°, and OCoN 96.22(7)°).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 28–31.Original Russian Text Copyright © 2005 by Aleksandrov, Shirokii, Sergienko.     

Crystal structure of hexadimethylsulfoxidenickel(II) tetraisothiocyanatozincate

A new complex, hexadimethylsulfoxidenickel(II) tetraisothiocyanatozincate [Ni(DMSO)₆][Zn(NCS)₄](I), is synthesized. Its crystal structure is determined by X-ray diffraction analysis. Compound I forms light green, monoclinic crystals shaped like plates: a = 8.4358(8) Å ,b = 21.655(2) Å, c = 10.8351(8) Å = 105.162(7)°, V = 1910.4(3) ų, space group P2₁/m, Z = 2, (calcd) = 1.434 g/cm ³ , µ= 1.699mm ^–1. The Zn atom has a tetrahedral environment, while the Ni atom has an octahedral environment.Translated from Koordinatsionnaya Khimiya, Vol. 30, No. 12, 2004, pp. 939–942.Original Russian Text Copyright © 2004 by Cherkasova, Tsalko.     

Synthesis and crystal structure of a mixed-ligand compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV)

Reaction of dibutyltin dichloride with 4-chlorobenzohydroxamic acid and 4-chlorobenzoic acid in 1:1:1 stoichiometry yields the new title compound di-n-butyl(4-chlorobenzoxy)(4-chlorobenzohydroxamato)tin(IV) 1, which had been characterized by IR and ¹H, ¹³C, ¹¹⁹Sn NMR. Single X-ray crystal structure analysis has been determined for 1, which crystallizes as the five-coordinate mixed-ligand dibutyltin(IV) complex containing both monodentate and bidentate ligands. The crystal structure of the compound reveals that the tin atom adopts distorted trigonal bipyramidal geometry with the Bu groups trans to each other. The C-Sn-C angle is 145.9(3)°, and the Sn-O bonds are 2.083(4) and 2.158(4) Å in one ligand and 2.242(4) Å in the other. An unusual feature of the structure is the presence of a kind of intermolecular hydrogen bonding which serves to stabilize the crystal structure.     

Crystallographic, vibrational and theoretical studies of 2,3-diaminopyridinium selenate

The new organic–inorganic salt, 2,3-diaminopyridinium selenate, has been synthesized and characterized by means of single-crystal X-ray crystallography, FT-IR and FT-Raman spectroscopy. A diprotonated organic ligand, H₂^1,3L²⁺, existing in the crystal structure was theoretically shown to be the most stable cationic species of 2,3-diaminopyridine. The weak non-covalent forces of N–H?O type between the hydrogen atoms of the amino and ammonio groups of 2,3-diaminopyridinium cation and oxygen atoms of tetrahedral selenate anions determine three-dimensional arrangement with complex network of intermolecular interactions of hydrogen bond type (donor–acceptor distances from 2.697(3) Å to 3.088(3) Å). Vibrational spectra have been discussed in comparison with X-ray results. Juxtaposition of spectra of the complex with the pure organic ligand and deuterated analogue of the title compound allowed to give reliable assignments of most observed vibrational bands. Presented data can be useful in elucidation of molecular mechanism of uptake of tetrahedral SeO₄²⁻ anion by the living organisms.     

Molecular structure of the cobalt(ii) chloride complex with triphenyl-N-(2-pyrimidyl)phosphineimine

An X-ray structural study of the cobalt(ii) chloride complex with triphenyl-N-(2-pyrimidyl)phosphineimine has been performed (automatic diffractometer, Mo-–K , 2916 observed reflections, the heavy-atom method, the least squares method in anisotropicisotropic approximation toR=0.043). The crystals are monoclinic,a=15.979(6) Å,b=17.391(6) Å,c=14.976(6) Å, =104.21(2)°,V=4034(5) ų,d _calc=1.384 g cm^–3,Z=4, space groupP2₁/c. The Co atom has a distorted tetrahedral coordination by two Cl atoms (2.268(2) Å and 2.278(3) Å) and two N atoms (2.030(4) Å and 2.025(5) Å) of the two pyrimidine heterocycles. The Cl-Co-Cl and N-Co-N bond angles are equal to 107.7(1)° and 123.4(2)°, respectively. Additional weak coordination of the Co atom by two N atoms of the imine groups [Co...N 2.982(4) Å and 3.045(4) Å] is also observed in the molecule of the complex, and this coordination changes the nearest environment of the Co atom to distorted octahedral coordination. The lengths of the phosphorus-imine P=N bonds are 1.596(6) Å and 1.585(6) Å. The results obtained are compared with previous structural investigations of similar complexes of transition metals with iminophosphoranes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1203–1206, July, 1993.     

Chloro(N-ethyl-1,3-imidazolidine-2-thione)gold(I): Spectroscopic studies and x-ray structure

Summary Chloro(N-ethyl-1,3-imidazolidine-2-thione)gold(II) crystallizes in the triclinic space group P¯I with cell dimensions:a=7.213(2)Å,b=7.857(7)Å,c=9.056(3)Å, =108.54°, =100.06(3)°, =107.27(4)° and Z=2.,The structure was refined by a least squares method to a conventional R factor of 7.3%, using 2157 reflections. The metal atom is bonded through the sulfur atom of the ligand which is consistent with the¹³C n.m.r. spectra of the complexes in d₆-acetone. The structure of the complex and coordination around metal are compared with other linear gold(I) complexes.     

Neptunium(V) Perrhenate Complex with 1,10-Phenanthroline [(NpO2)(ReO4)(Phen)(H2O)2]: Crystal Structure and Absorption Spectra

Neptunium(V) perrhenate complex [(NpO₂)(ReO₄)(Phen)(H₂O)₂] was synthesized with 1,10-phenanthroline as a ligand. Its composition and structure were determined by X-ray diffraction analysis. The coordination polyhedron of the Np atom is a pentagonal bipyramid. The nearest surrounding of the neptunoyl ion includes the oxygen atom of the ReO₄ anion, two nitrogen atoms of phenanthroline, and the oxygen atoms of two water molecules. The crystals of the compound are monoclinic. The main crystallographic parameters are the following: space group P2₁/c, unit cell parameters a = 7.288(1) Å, b = 10.513(2) Å, c = 20.936(4) Å, = 96.939(5)°, Z = 4, V = 1592.2(5) ų. Absorption spectra of the compound in visible and IR regions are reported.     

Crystal Structure of Diaqua(1,2-bis(2-(o-hydroxy-phenoxy)ethyloxy)ethane)(isothiocyanato)strontium Thiocyanate

The aqua complex of podand 1,2-bis(2-(o-hydroxyphenoxy)ethyloxy)ethane (L) with strontium thiocyanate of the composition [Sr(NCS)L(H₂O)₂]⁺ · SCN^– (I), was synthesized and studied by X-ray diffraction analysis: space group P 2₁/c, a = 17.730 Å, b = 8.558 Å, c = 18.169 Å, = 116.15°, Z = 4. The structure was solved by direct method and anisotropically refined by the full-matrix least-squares method to R = 0.039 for 4333 independent reflections (CAD4 autodiffractometer, MoK ). Structure I contains complex cation [Sr(NCS)L(H₂O)₂]⁺ of the host–guest type. The coordination polyhedron of Sr²⁺ cation (coordination number 9) is a distorted pentagonal bipyramid with four oxygen atoms at the benzene rings of the L podand and the oxygen atom of one water molecule in its base, the N atom of the SCN^– ligand at its single vertex, and with the remaining two O atoms of the L podand and O atom of another water molecule at a triple vertex. In a crystal, the complex cations and SCN^– anions are joined through the hydrogen bonds to form bulky layers parallel to the xy plane.     

Crystal structure of Ir(acac-O,O)2(acac-C3)(pyridine)

Ir(acac-O,O)₂(acac-C³)(pyridine), 1 is synthesized, and its crystal structure is determined by single crystal X-ray diffraction. In the complex, the central Ir(III) atom displays a distorted octahedral geometry wherein the equatorial positions are occupied by four oxygen atoms of two acetylacetone ligands, and the apical positions are coordinated by a carbon atom of one acetylacetone ligand and a nitrogen atom of pyridine.     

CuO micro plates from a 3D metallo-organic framework (MOF) of a binary copper(II) complex of N,N-bis(2-hydroxyethyl)glycine

The crystal structure of [Cu(Bic)₂] (1) (Bic⁻ = N,N-bis(2-hydroxyethyl)glycinate), was determined by single-crystal X-ray diffraction techniques. [Cu(Bic)₂]: monoclinic system, space group P21/n. In the complex, the copper atom is tetra coordinated by two oxygen atoms of the carboxylato groups and two nitrogen atoms of the bicinate ligand, forming a distorted square planar coordination geometry. The molecular structure of the complex in solution is the same as that of the crystalline state, as supported by ESR and electronic spectra in solution. The blue complex 1 on heating at ∼500 °C for 6 h results in the formation of black CuO (Tenorite) micro plates.     

Synthesis of Re(I) complexes bearing tridentate 2,6-bis(7-azaindolyl)phenyl ligand with green emission properties

The Re(I) complexes bearing 2,6-bis(7^′-azaindolyl)phenyl ligand as a tridentate ligand were synthesized by treatment with Re₂(CO)₁₀. The structures of the complexes were confirmed by X-ray crystallography. Both 7-azaindolyl ligands of Re(I) complexes are present in butterfly forms. The Re-C_ipso bonds showed a partial double bond character by π back-donation between the phenyl moiety and Re atom. In THF solution at room temperature, these complexes exhibited green emission (λ_em=510 nm), which is considered to be attributable to MLCT (dz²(Re) →π^* (7^′-azaindolyl group)) transition containing π→π^* (7^′-azaindolyl group) transition.     

Synthesis and characterization of new macrocyclic Schiff base derived from 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes

A new macrocyclic ligand, 1,3,5-triaza-2,4:7,8:16,17-tribenzo-9,12,15-trioxacyclooktadeca-1,5-dien (L) was synthesized by reaction of 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane. Then, its Cu(II), Ni(II), Pb(II), Co(III) and La(III) complexes were synthesized by template effect by reaction of 2,6-diaminopyridine and 1,7-bis(2-formylphenyl)-1,4,7-trioxaheptane and Cu(NO₃)₂ · 3H₂O, Ni(NO₃)₂ · 6H₂O, Pb(NO₃)₂, Co(NO₃)₂ · 6H₂O, La(NO₃)₃ · 6H₂O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV–Vis spectra, magnetic susceptibility, thermal gravimetric analysis, conductivity measurements, mass spectra and cyclic voltammetry. All complexes are diamagnetic and Cu(II) complex is binuclear. The Co(II) was oxidized to Co(III). The comparative electrochemical studies show that the nickel complex exhibited a quasi-reversible one-electron reduction process while copper and cobalt complexes gave irreversible reduction processes in DMSO solution.     

Pentakis(carbamide)dioxoneptunium(V) Nitrate [NpO2{OC(NH2)2}5](NO3): Synthesis,Crystal Structure,and Some Properties

X-ray diffraction and spectroscopic data for a new Np(V) compound, namely, [NpO₂{OC(NH₂)₂}₅](NO₃) (I) are presented. Crystals are monoclinic, space group P2₁, a = 11.142(2) Å, b = 7.6379(9) Å, c = 11.143(2) Å, = 108.9(1)°, Z = 2, V = 897.1(2) ų. The neptunium atom has a typical pentagonal-bipyramidal environment with five oxygen atoms of the carbamide molecules in the equatorial plane. The nitrate ion is in the outer sphere. Carbamide is a strong molecular ligand with respect to Np(V) and hence, cation–cation bonds of the NpO₂ ⁺ ions are not realized in structure I. The wave length of the f–f transition in the electronic absorption spectra of crystalline complex I and Np(V) in a saturated carbamide solution is virtually the same and is equal to 991 nm.     

Synthesis, structure determination, and infrared spectroscopy of (NpO2)2(SO4)(H2O)4: Prevalence of cation-cation interactions and cationic nets in neptunyl sulfate compounds

The compound (NpO₂)₂(SO₄)(H₂O)₄ was synthesized by evaporation of a Np⁵⁺ sulfate solution. The crystal structure was determined using single crystal X-ray diffraction and refined to an R₁=0.0310. (NpO₂)₂(SO₄)(H₂O)₄ crystallizes in triclinic space group P-1, a=8.1102(7) Å, b=8.7506(7) Å, c=16.234(1) Å, α=90.242(2)°, β=92.855(2)°, γ=113.067(2)°, V=1058.3(2) Å³, and Z=2. The structure contains neptunyl pentagonal bipyramids that share vertices through cation-cation interactions to form a sheet or cationic net. The sheet is decorated on each side by vertex sharing with sulfate tetrahedra, and adjacent sheets are linked together through hydrogen bonding. A graphical representation of (NpO₂)₂(SO₄)(H₂O)₄ was constructed to facilitate the structural comparison to similar Np⁵⁺ compounds. The prevalence of the cationic nets in neptunyl sulfate compounds related to the overall stability of the structure is also discussed.     

Synthesis and characterization of a novel η 2-iminoacyl monocyclopentadienyl titanium(IV) complex

An unusual complex, [CpTi(η²-(C,N)-2-ArNH–C₆H₄C=NAr)Cl₂] (Ar?=?2,6- ⁱ Pr₂C₆H₃) (1) has been synthesized and characterized by elemental analysis, NMR spectra, and single crystal X-ray diffraction. The ¹³C NMR resonance of the imine carbon atom of 1 at δ?221?ppm is consistent with the η²-(C,N) binding. This was confirmed by single crystal X-ray diffraction study of 1. In the complex, Ti atom is five-coordinate with a η²-bound iminoacyl ligand and one Cp ligand occupying the axial position in a distorted square pyramid.     

Crystal Structure of the Diaqua(1,10-Diaza-18-Crown-6) (Tetrafluorosuccinato-O)barium Complex

The diaqua(1,10-diaza-18-crown-6)(tetrafluorosuccinato-O)barium complex [Ba(DA18C6)(C₄F₄O₄)(H₂O)₂] (I) is synthesized and studied using X-ray diffraction analysis: space group P2₁/n, a = 16.342 Å, b = 8.989 Å, c = 17.087 Å, = 107.09°, Z = 4. The structure was solved by the direct method and refined by the full-matrix least squares method in anisotropic approximation to R = 0.075 for all 3515 unique reflections (CAD4 automated diffractometer, MoK ). Complex I exists in the crystal as individual host–guest molecules of the aforementioned composition. The Ba²⁺ cation (coordination number 9) is located in the void of the DA18C6 macrocycle and is coordinated by its six O and N heteroatoms. It is also coordinated by the O atom of the tetrafluorosuccinate ligand and the O atom of the water molecule on one side of the macrocycle and by the O atom of the second water molecule on the other macrocycle side. The DA18C6 ligand has a crown conformation with approximate D _3d symmetry. The complex molecules in the crystal are combined into infinite two-dimensional layers by intermolecular hydrogen bonds.     

Interaction of Np(V) with N,N-Dimethylacetamide

A new Np(V) complex [(NpO₂)(NO₃)(DMAA)₂(H₂O)] was synthesized and its crystal structure was determined. Its absorption spectra were recorded in IR and near-IR regions. The unit cell parameters are a = 9.389(3) Å, b = 8.075(3) Å, c = 20.956(7) Å, = 92.53(3)°, space group P2₁/c, Z = 4, V = 1585.8(9) ų, R = 0.054, wR(F ²) = 0.170. The coordination polyhedron of the Np atom is a pentagonal bipyramid with the O atoms of two DMAA molecules, bidentate nitrate ion, and the water molecule in its equatorial plane.     

Synthesis and crystal structures of the chromium(II) and chromium(III) hexafluoroacetylacetonate complexes trans-Cr(hfac)2(thf)2 and Cr(hfac)3

Treatment of a tetrahydrofuran solution of CrCl₂(thf) with Na(hfac), hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate, followed by crystallization from diethyl ether, affords the six-coordinate chromium(II) complex Cr(hfac)₂(thf)₂. The crystal structures of Cr(hfac)₂(thf)₂ and the chromium(III) complex Cr(hfac)₃ have been determined by single-crystal X-ray diffraction. Cr(hfac)₂(thf)₂ adopts a trans octahedral geometry, in which the Cr–O(hfac) and Cr–O(thf) distances are 1.936(3) and 2.019(6) Å, respectively. Cr(hfac)₃ is an octahedral compound with a Cr–O distance of 1.943(5) Å. Structural comparisons with related molecules are given.