Crystal structures of azido or thiocyanato-coordinated nickel(II) complexes with tridentate Schiff bases

A new azido-coordinated nickel(II) complex [NiL¹(N₃)] (1) and a new thiocyanato-coordinated nickel(II) complex [NiL²(NCS)] (2), where L¹ and L² are the monoanionic forms of Schiff bases 2-[(2-isopropylaminoethylimino)methyl]-6-methylphenol and 2-[(2-dimethlaminoethylimino)methyl]-6-methylphenol respectively, are prepared and structurally characterized by elemental analysis, IR spectra, and single crystal X-ray crystallography. Complex 1 crystallizes in the triclinic space group P-1 with unit cell dimensions a = 8.812(2) Å, b = 9.433(3) Å, c = 9.488(2) Å, α = 81.933(2)°, β = 69.925(2)°, γ = 84.591(2)°, V = 732.5(3) ų, Z = 2, R ₁ = 0.0291, and wR ₂ = 0.0734. Complex 2 crystallizes in the monoclinic space group P2₁/n with unit cell dimensions a = 7.4497(4) Å, b = 6.1933(3) Å, c = 31.5126(18) Å, β = 92.484(2)°, V = 1452.57(13) ų, Z = 4, R ₁ = 0.0307, and wR ₂ = 0.0668. The Ni atom in each of the complexes is coordinated by three donor atoms of the Schiff base ligand and by one N atom of the azide or thiocyanate ligand, forming a square planar geometry. The azide and thiocyanate anions readily coordinate to the complexes as secondary ligands.     

Construction of chlorido-bridged dinuclear copper(II) complexes with similar tridentate Schiff bases

Two new chlorido-bridged dinuclear copper(II) complexes [Cu₂Cl₂(L¹)₂] (1) and [Cu₂Cl₂(L²)₂] (2), where L¹ and L² are the deprotonated form of Schiff bases 2-[1-(2-morpholin-4-ylethylimino)ethyl]phenol (HL¹) and 2-[1-(2-piperidin-1-ylethylimino)ethyl]phenol respectively, are prepared and structurally characterized by elemental analysis, IR spectra, and single crystal X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 8.0816(2) Å, b = 19.1780(3) Å, c = 9.6757(3) Å, β = 106.465(2)°, V = 1438.13(6) ų, Z = 2, R ₁ = 0.0409, and wR ₂ = 0.1085. Complex 2 crystallizes in the monoclinic space group P2₁/c with unit cell dimensions a = 7.7640(10) Å, b = 19.930(3) Å, c = 9.628(2) Å, β = 103.890(3)°, V = 1446.2(4) ų, Z = 2, R ₁ = 0.0634, and wR ₂ = 0.1316. Each Cu atom in the complexes is coordinated by three donor atoms of the Schiff bases and by two bridging Cl atoms, forming square pyramidal geometry. The Cl anions are preferred bridging groups for the construction of dinuclear copper complexes with tridentate Schiff bases.     

A zwitterionic monoalkylated derivative of [Pt2(μ-S)2(PPh3)4] from 1,3-propanesultone

Reaction of dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂(PPh₃)₄] with 1,3-propanesultone gives the novel zwitterionic monoalkylated thiolate complex [Pt₂(μ-S){μ-S(CH₂)₃SO₃}·(PPh₃)₄], which was characterized by NMR spectroscopy, electrospray ionisation mass spectrometry, and a single crystal X-ray structure determination. Crystals are monoclinic, space group P2(1)/c with unit cell dimensions a = 16.8957(3) Å, b = 15.5031(3) Å, c = 28.0121(5) Å, β = 99.780(1)°, for Z = 4.     

Synthesis and crystal structure of a novel tri-nuclear nickel(II) complex derived from N,N′-(2-hydroxypropane-1,3-diyl)bis(salicylaldimine)

A novel tri-nuclear nickel(II) complex, [Ni₃L₂(μ₂-η¹:η¹-OAc)₂(μ₁-η¹:η⁰-OAc)₂] · H₂O (H₂L is N,N′-(2-hydroxypropane-1,3-diyl)-bis(salicylaldimine), was prepared. The complex was characterized by elemental analysis, IR spectra, and single crystal X-ray determination (CIF file CCDC no. 993163). Crystal of the complex crystallizes in the monoclinic space group P2₁/n. The unit cell parameters: a = 12.5602(9), b = 13.2104(10), c = 15.0329(10) Å, β = 113.194(2)°, V = 2292.7(3) ų, Z = 2, R ₁ = 0.0506, wR ₂ = 0.1342, S = 1.067. The complex possesses crystallographic inversion center symmetry. The Ni atoms are in octahedral coordination spheres. The Ni?Ni distances are 3.022(1) Å.     

Dihydrogen activation promoted by homonuclear ion pairs involving cobalt(II) and cobalt(−I)

Acyltetracarbonyls have been shown to be formed from the reaction of hexene with CO/H₂ (1/1) mixtures (P(CO) = P(H₂) = 300 mmHg) in THF/H₂O at room temperature catalysed by homonuclear Co_II, Co^?I ion pairs.     

Hybrid open-frameworks (MIL-n): Syntheses and structures of 2-dimensional gallium methylphosphonates (MIL-23) and 3-dimensional copper vanadium methyldiphosphonate (MIL-24)

The hydrothermal synthesis and the structure determination from powder or single crystals X-ray diffraction of 3 new metallophosphonates are presented. Crystal data: Ga(OH)_0.28F_0.72PO₃(CH₃): P2₁/c (n∘ 14), a = 7.7912(7) Å, b = 7.2310(6) Å, c = 9.3114(8) Å, β = 106.873(2) °, V = 502.00(8) Å ³, Z = 4, R₁(F) = 0.0409, wR₂(F²) = 0.0933 for 1 266 reflections I > 2 σ (I) with 77 parameters. Ga₃(OH)₃F₃(MePO₃)₂ H₂N(CH₂)₃NH₃: P-3 (No. 147), a = b = 7.2514(2) Å, c = 7.9413(2) Å, V = 361.6(3) ų, Z = 6, R_F = 7.95, R_Bragg = 7.18, R_wp = 17.3, R_p = 12.0. (V^IVO(H₂O))(Cu^II(H₂O))O₃P-CH₂-PO₃: P2₁2₁2₁ (No. 19), a = 6.3884(3) Å, b = 10.7284(4) Å, c = 11.2762(5) Å, V = 772.84(6) ų, Z = 4, R₁(F) = 0.0395, wR₂(F²) = 0.0861 for 2 012 reflections I > 2 σ (I) and 128 parameters.     

The crystal structure of a complex cerium(III) molybdate containing a dimolybdate chain,Ce2(MoO4)2(Mo2O7)

Ce₂(MoO₄)₂(Mo₂O₇) crystallizes in the triclinic system with unit cell dimensions (from single-crystal data) a = 11.903(8), b = 7.509(5), c = 7.385(5) Å, α = 94.33(8), β = 97.41(8), γ = 88.56(7)°, and space group $\text{P}\text{1}\text{, z = 2}$. The structure was solved using Patterson (“P1 method”) and Fourier techniques. Of the 8065 unique reflections measured by counter techniques, 6314 with I ≥ 3σ(I) were used in the least-squares refinement of the model to a conventional R of 0.035 (R_w = 0.034). The structure of Ce₂(MoO₄)₂(Mo₂O₇) consists of dimolybdate chains of the K₂Mo₂O₇ and (NH₄)₂Mo₂O₇ type separated by isolated MoO₄ tetrahedra and cerium(III) polyhedra.     

The phase equilibria study in the system Na4P2O7Mg2P2O7

The phase equilibria in the system Na₄P₂O₇Mg₂P₂O₇ were studied by means of DTA, hot stage microscopy and X-ray diffraction analysis. There is one intermediate compound in the system which melts congruently at 832°C of chemical composition Na₇Mg_4.5(P₂O₇)₄. It crystallizes in the triclinic system with unit cell constants: a = 10.882(1), b = 9.734(1), c = 6.372(1) Å; α = 112.49(1), β = 99.63(1), γ = 107.40(1)°.     

Overexpression in Catharanthus roseus hairy roots of a truncated hamster 3-hydroxy-3-methylglutaryl-CoA reductase gene

Catharanthus roseus (L.) G. Don hairy roots harboring hamster 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) (EC 1.1.1.88) cDNA without membrane-binding domain were evaluated by quantifying the levels of sterols and some indol-alkaloids. Clone 236, with the highest hybridization signal, had the lowest soluble and microsomal HMGR activity and produced more ajmalicine and catharanthine than the control but had reduced campesterol concentration. Clone 19, with low hybridization signal, had high soluble HMGR activity and produced high levels of campesterol and five to seven times more serpentine than the control but a low level of ajmalicine and no accumulation of catharanthine. These results suggest a possible role for HMGR in indole alkaloid biosynthesis and a possible cosuppression of both the endogenous and foreign HMGR genes in clone 236.     

Hyperfine structure quantum beat spectroscopy of Tl statesn 2 P 3/2 (n=10−13) with pulsed two-photon excitation

By quantum beat spectroscopy with pulsed two-photon excitation the hyperfine constants of the Thallium states 6s ² np ² P _3/2 (n=10?13) are determined: 2A(10P _3/2)=77.73 (74) MHz, 2A(11P _3/2)=48.82 (49) MHz, 2A(12P _3/2)=32.34 (45) MHz and 2A(13P _3/2)=23.08 (35) MHz.     

Metal-phenoxyalkanoic acid interactions—12: The crystal and molecular structure of μ-aqua-di-μ-[(2-chlorophenoxy)ethanoato-(O,O′)]-bis[(2-chlorophenoxy)-ethanoato-bis(pyridine)nickel(II)]-water (1/1)

The crystal structure of the pyridine adduct of nickel (2-chlorophenoxy)-ethanote, {[Ni₂(2-CPA)₄(py)₄(H₂O)] · H₂O}, has been determined from three dimensional X-ray data at 293 K. Crystals of the complex are triclinic, space group P$\text{1}$, with two dimers in a unit cell of dimensions a = 21.740(5), b = 14.312(7), c = 9.044(2)Å, α = 96.69(4), β = 84.99(4), γ = 101.20(3)°. The structure was solved by direct methods and refined to 0.059 for 2682 ‘observed’ reflections. The dimer consists of two face-to-face NiO₄N₂ octahedra joined at their apical positions by a bridging water molecule [Ni(1)-Ow; 2.14(1)Å; Ni(2)-Ow, 2.10(1)Å; Ni(1)-Ôw-Ni(2), 116.9(4)°]. Two bidentate carboxyl groups of the 2-CPA molecules bridge the other two corners of the triangular face while the other two 2-CPA ligands are unidentate [Ni-O, 2.05(1)Å (mean)]. The coordination about each Ni is completed by two cis-related pyridine nitrogens [Ni-N; 2.11(1)Å (mean)]     

Ligand substitution reaction of (μ-H)Os3(CO)10(μ-COMe) with 1,1'-bis(diphenylphosphino) ferrocene

Reaction of (μ-H)Os₃(CO)₁₀(μ-COMe) with 1,1'-bis(diphenylphosphino)-ferrocene (dppf) produces (μ-H)Os₃(CO)₈(μ-COMe){μ-η²-(η⁵-C₅H₄PPh₂)₂Fe} (1) and (μ-H)₂Os₃(CO)₇(μ-COMe){μ-η³-(η⁵-C₅H₃PPh₂)Fe(η⁵-C₅H₄PPh₂)} (2). Thermolysis of 1 leads quantitatively to 2. These compounds have been characterized by ¹H, ³¹P, and ¹³C NMR, IR, and mass spectroscopies. Compound 2 crystallizes in space group P 2₁/c with a = 11.898(2), b = 21.266(3), c = 18.262(3) Å, β = 104.71(1)°, V = 4469(1) ų, Z = 4, and R_F = 0.029.     

Crystal structure and spectroscopic properties of A[VO2(SO4)(H2O)2] · H2O (A = K, Rb, Tl, NH4) compounds

The crystal structure of dioxovanadium(V) sulfate trihydrates A[VO₂(SO₄)(H₂O)₂] · H₂O, where A is K, Rb, Tl, or NH₄, has been determined based on a combination of neutron and X-ray diffraction data. The compounds are isostructural and have a monoclinic lattice (space group P2₁, Z = 2) with unit cell parameters a = 6.24535(8), 6.26016(7), 6.25817(5), and 6.2500(1) Å; b = 9.8417(1), 9.99736(8), 9.96217(9), and 9.9742(1) Å; c = 6.52113(8), 6.69303(5), 6.70379(6), and 6.70334(9) Å; β = 106.99(1)°, 107.83(1)°, and 107.83(1)°, 107.99(1)°, respectively. The SO₄ tetrahedra and VO₄(H₂O)₂ octahedra share an oxygen vertex to form infinite isolated chains. Atoms A have CN = 10. IR and Raman spectroscopy data are reported.     

Crystal structure of olanzapinium benzoate (1:1)

Olanzapinium benzoate, 1-methyl-4-(2-methyl-10H-thieno[2,3-b][1,5]benzodiazepin-4-yl)-piperazin-1-ium benzoate, (C₁₇H₂₁N₄S)⁺(C₇H₅O₂)^? (I), crystallizes in triclinic space group P-1 with unit cell dimensions a = 9.2957(6) Å, b = 11.2416(7) Å, c = 12.0003(8) Å; α = 64.585(1)°, β = 87.568(1)°, γ = 83.248(1)°; V = 1124.8(1) ų. The asymmetric part of the structure comprises a singly charged olanzapinium cation and a singly charged benzoate anion. The central 1,5-diazepine ring adopts the expected boat conformation, while the piperazine ring favors the chair conformation. The olanzapinium and benzoate ions are linked by intermolecular N-H...O hydrogen bonds forming infinite chains running along the c-axis of the crystal.     

Two Modifications of Y2Piv6(Hpiv)6 crystals: Synthesis and structures

Crystals of two modifications of yttrium pivalate solvate Y₂Piv₆(HPiv )₆(HPiv = (CH₃)₃CCOOH) are synthesized and studied by single-crystal X-ray diffraction analysis. The 3α-modification crystallizes in the monoclinic system, a = 16.394(2) Å, b = 11.948(4) Å, c = 20.352(3) Å, β = 108.73(3)°, Z = 4, space group P2₁/n, R ₁ = 0.105. Crystals of the β-modifications are also monoclinic, a = 21.617(4) Å, b = 36.559(4) Å, c = 29.930(4) Å, β = 104.40(2)°, Z = 12, space group P2₁/c, R ₁ = 0.050. The molecular structures of crystals of the α-and β-modifications consist of the Y₂(μ₂-Piv)₄(Piv)₂(HPiv)₆ dimers. The Y atoms with a distorted antiprismatic coordination surrounding of the O atoms (Y-O 2.23–2.53 Å) are linked by four bridging bidentate pivalate anions and form the structural fragment shaped into a distorted lantern. Monodentate Hpiv molecules participate in the formation of intramolecular hydrogen bonds with Piv ligands. Crystal structures of the α-and β-modifications differ in packing of the Y₂Piv₆(HPiv)₆ dimers and in centrosymmetric nature of the dimers in the structure of the α-modification.     

Panchromatic dirhodium photocatalysts for dihydrogen generation with red light

A series of three dirhodium complexes cis-[Rh₂(DPhB)₂(bncn)₂](BF₄)₂ (1, DPhB = diphenylbenzamidine; bncn = benzocinnoline), cis-[Rh₂(DPhTA)₂(bncn)₂](BF₄)₂ (2, DPhTA = diphenyltriazenide), and cis-[Rh₂(DPhF)₂(bncn)₂](BF₄)₂ (3, DPhF = N,N′-diphenylformamidinate) shown to act as single-molecule photocatalysts for H₂ production was evaluated. Complexes 1–3 are able to generate H₂ in the absence of any other catalyst in homogenous acidic solution upon irradiation with red light in the presence of the sacrificial electron donor BNAH (1-benzyl-1,4-dihydronicotinamide). The excited state of each complex is reductively quenched by BNAH, producing the corresponding one-electron reduced complex. The latter is also able to absorb a photon and oxidize another BNAH molecule, producing the doubly-reduced, activated form of the catalyst that is able to generate H₂. The present work shows the effect of substitution on the bridging ligands on the driving force for reductive quenching and hydricity of the proposed active intermediate, both of which affect the efficiency of hydrogen production. Complexes 1–3 operate following a double reductive quenching mechanism and, importantly, are active with red light. This work lays the foundation for the design of single-molecule photocatalysts that operate from the ultraviolet to the near-infrared, such that solar photons throughout this entire range are harnessed and utilized for solar energy conversion.

Three dirhodium complexes cis-[Rh₂(DPhB)₂(bncn)₂](BF₄)₂, cis-[Rh₂(DPhTA)₂(bncn)₂](BF₄)₂ and cis-[Rh₂(DPhF)₂(bncn)₂](BF₄)₂ are shown to act as single-molecule photocatalysts for H₂ production.     

Evaluation of the probability of reaction of fast oxygen atoms with polymers and graphite

On the basis of analysis of published data on the reaction efficiency of various polymer materials and graphite in their interaction with fast oxygen atoms (energy of about 4.5 eV) as obtained in flight tests of materials in low-Earth orbits of the International Space Station and ground tests, probability P _r of chemical oxidation reactions accompanied by ablation has been evaluated. Estimates have been made for 33 polymers consisting of carbon, hydrogen, oxygen, and nitrogen and graphite for two extreme cases when the carboncontaining oxidation products are either CO or CO₂ alone. The average probability values found are P _r(CO)(av) = 0.184 and P _r(CO₂)(av) = 0.317. The probability values range from P _r(CO) = 0.604 and P _r(CO₂) = 0.963 for allyl diglycol carbonate to P _r(CO) = 0.038 and P _r(CO₂) = 0.075 for pyrolytic graphite.     

The crystal and molecular structure of isoalfileramine dihydrobromide

The crystal and molecular structure of isoalfileramine dihydrobromide has been determined from 3-dimensional single crystal X-ray diffraction data collected by counter techniques. Isoalfileramine is a cyclized derivative of the novel alkaloid, alfileramine, which has been isolated from leaves of Zanthoxylum punctatum Vahl. The crystals of isoalfileramine dihydrobromide were triclinic, space group P1? (No. 2), with two formula units in a unit cell of dimensions a = 16.380(12) Å, b = 9.917(7) A, c = 10.648(7) A, α = 116.39(2)°, β = 91.10(2)° and γ = 101.40(2)°. The structural model, which employed anisotropic thermal parameters only for the bromide ions, was refined using full matrix least squares methods to an R value of 0.089 (R_w = 0.090) for 1053 independent reflections with F² > 3σ(F²). Isoalfileramine dihydrobromide is shown to be a unique pentacycle exhibiting a strained pyran ring. This work was critical in establishing structure for the parent alkaloid, alfileramine, and pointed out the clear structural relationship of alfileramine to tetrahydrocannabinols.     

An improved model of the fringing fields of a quadrupole mass filter

The fringing field region of a quadrupole mass filter is modelled using an iterative finite difference technique to solve Laplace's equation for the electrostatic potential. The results are used to formulate an expression f(z) such that the electrostatic potential of the fringing field, F(x, y, z, t) may be written in the form F(x, y, z, t) = f(z) φ(x, y, t), where φ(x, y, t) is the hyperbolic field of the quadrupole. The function f(z) is expressed in the form f(z) = 1 - exp {- az - bz²}), where a and b are constants and z is in units of r_O, where 2r_O is the spacing of the quadrupole rods. The effect of the distance from the quandrupole rods to the end plate of the quadrupole mass filter, d on f(z) is investigated and the results presented show that for d < 0.125 r_O the function f(z) does not alter significantly.     

The unexpected decarbonylation of a molybdenum(O) dithiocarbamate and the formation of a molybdenum(V) dimeric product: Crystal structure of di-μ-sulfido-bis[oxo(pyrrolidinedithiocarbamato)molybdenum(V)]

The interaction of molybdenum hexacarbonyl with ammonium pyrrolidinedithiocarbamate in warm dimethylsulfoxide solution gives not the expected complex [NH₄][Mo(CO)₄(S₂CN(CH₂)₄)] but the molybdenum(V) dimer, di-μ-sulfido-bis[oxo(pyrrolidinedithiocarbamato)molybdenum(V)]. The structure of this oxidized product [MoO(S₂CN(CH₂)₄)S]₂ (1) was determined by single-crystal X-ray diffraction analysis. The crystals are triclinic, space group P$\text{I}$ with two molecules in a unit cell of dimensions a = 8.775(1), b = 16.592(2), c = 6.661(1) Å, α = 97.67(1), β = 97.89, γ = 80.23(1)°. The structure was solved by the heavy-atom method and refined by block-diagonal least-squares calculations to R = 0.037 for 3772 observed data. In the binuclear complex the two Mo atoms are bridged via two S atoms [Mo-S 2.303-2.317(1) Å]. Each Mo atom is also coordinated by a terminal O atom [1.688(4) and 1.682(4) Å] and two S atoms from the bidentate ligand [Mo-S 2.455-2.475(1) Å]. The geometry around the metal atoms is distorted square pyramidal.