Synthesis, spectroscopy, and X-ray structures of fac-(CO)3(dppe)MnSC(S)H, fac-(CO)3(dppe)ReSC(S)H, fac-(CO)3(dppp)ReSC(S)H, and fac-(CO)3(dppb)ReSC(S)H

The monodentate dithioformato complexes, fac-(CO)₃(dppe)MnSC(S)H (1), fac- (CO)₃(dppe)ReSC(S)H (2), fac-(CO)₃(dppp)ReSC(S)H (3), and fac-(CO)₃ (dppb)ReSC(S)H (4), where dppe is 1,2-bis(diphenylphosphino)ethane, dppp is 1,3-bis(diphenylphosphino)propane, and dppb is 1,4-bis(diphenylphosphino)butane, were synthesized from the treatment of the corresponding hydrides, fac-(CO)₃ (P-P)MSC(S)H with CS₂. Compounds 1–4 crystallize in the monoclinic crystal system: for 1, space group = P2₁/c, a = 15.3139(3) Å, b = 9.7297(4) Å, c = 19.0991(6) Å, = 105.928(1), V = 2736.5 ų, Z = 4; for 2, space group = P2₁/c, a = 15.6395(8) Å, b = 9.8182(5) Å, c = 19.4153(11) Å, = 106.741(1), V = 2854.9(3) ų, Z = 4; for 3, space group = P2₁/n, a = 11.3570(10) Å, b = 19.465(2) Å, c = 15.5702(14) Å, = 104.776(2), V = 3328.3(5) ų, Z = 4; and for 4, space group = C2/c, a = 32.078(2) Å, b = 10.4741(6) Å, c = 19.0608(9) Å, = 94.315(2), V = 6386.1(6) ų, Z = 8.     

Tri-(nitrato)-bis-(hexamethylenetetramine)-nona-(aquo) neodymium (III): Synthesis,crystal structure,IR and Raman spectroscopy

This paper reports the structural and spectroscopic properties of tri-(nitrato)-bis-(hexamethylene-tetramine)-nona-(aquo)neodymium (III). The crystals are monoclinic, space groupP2₁/n,Z=4, witha=17.902(4),b=9.335(2),c=18.489(4)Å, B=112.07(2)°. The crystal structure consists of one [Nd(NO₃)₂(H₂O)₆]⁺ cation, two NO ₃ ^– anions coordinated to the neodymium atom, two hexamethylene tetramine molecules, third free NO ₃ ^– anion and three water molecules. The structure was refined to a finalR index 0.039 and weightedR _w 0.039 for 6221 observed reflections. The IR and Raman spectra are fully consistent with the crystallographic results.     

Tris-(thiocyanato)-bis-(hexamethylenetetramine)-nona-(aquo) lanthanum(III): synthesis, crystal structure, IR and Raman characterization

The title compound (LaC₁₅H₄₂N₁₁O₉S₃) was prepared and characterized by means of X-ray, IR and Raman measurements. The crystals are orthorhombic: Pnma (No. 62), a = 21.117(2), b = 14.736(2), c = 10.082(1) Å, and Z = 4. The structure consists of polyhedra with a La(III) ion in the center of them and hexamethylene molecules, which link these polyhedra. Each La(III) ion coordinates seven molecules of water and two thiocyanate ions via nitrogen atoms. The IR and Raman spectra, which have been obtained and interpreted, are in good agreement with X-ray results.     

Synthesis, spectroscopy, magnetism, and X-ray structures of hexakis(1-(2-chloroethyl)-tetrazole-N4)copper(II) salts

The compounds hexakis(1-(2-chloroethyl)-tetrazole-N4)copper(II) tetrafluoroborate mono(1-(2-chloroethyl)-tetrazole) (1) and hexakis(1-(2-chloroethyl)-tetrazole-N4) copper(II) perchlorate mono(1-(2-chloroethyl)-tetrazole) (2) were obtained from the crystallization of 1-(2-chloroethyl)-tetrazole (teec) with the respective copper salt. The X-ray structures are reported. Both compounds crystallize in the monoclinic space group C2/c for 1: a = 25.754(3) Å, b = 18.162(3) Å, c = 10.298(2) Å = 104.294(7)° and Z = 4 and for 2: a = 25.745(3) Å, b = 18.197(3) Å, c = 10.29355(3) Å = 104.512(10)° and Z = 4. The Cu^II ions are octahedrally surrounded by six teec ligands. One free teec ligand is present in the structures. The Cu–N distances in the centrosymmetrical units are 2.01, 2.04, and 2.39 Å in both compounds, consistent with a Jahn–Teller elongated octahedron. The ligand field spectra of both compounds show a signal in the visible range at about 15.200 cm^–1 and by an EPR spectrum the following values are found: g _| = 2.29 and g = 2.03. The compounds are both paramagnetic and the T value of 0.37 cm^–1 K mol^–1, which is associated with S = 1/2, is what would be expected for a mononuclear Cu^II complex.     

Molecular beam epitaxy growth and properties of GaAs/(AlGa)As p-type heterostructures on (100), (011), (111)B, (211)B, (311)B, and (311)A oriented GaAs

We report on a series of Be-doped GaAs/AlGaAs two-dimensional hole gas (2DHG) structures grown on (110), (111)B, (211)B and (311)B oriented substrates and compare their properties with high-mobility samples grown on (311)A using Si doping. The samples were prepared and grown under the same conditions so as to render them comparable. They are found to have mobilities which are strongly anisotropic within the plane. The highest mobility is found on the (110) surface with 100,000 cm² V⁻¹ s⁻¹, while the (211) surface gave the lowest values 10,000 cm² V⁻¹ s⁻¹. However, the later samples are found to have quantum Hall effect critical currents of >70 μA: an exceptionally high value for a hole gas which makes them suitable for metrology. All the samples show strong low-field positive magnetoresistance with resistance increases of up to 30% at magnetic fields of only 0.1 T. The presence of this feature on all the different planes shows that it does not depend upon the details of the band structure. It is identified with the lifting of the degeneracy of the spin sub-bands by the asymmetrical potential giving rise to a classical two-band magnetoreresistance.     

Diaquabis(5-methoxyindole-2-carboxylato)bis(3-picoline)nickel(II) Complex: Synthesis,Characterization, XRD,TGA, DFT and HSA

A new complex of diaquabis(5-methoxyindole-2-carboxylato)bis(3-picoline)nickel(II) (Ni(5-MeOI2CA)₂(3-pic)₂(H₂O)₂), was synthesized for the first time and characterized by elemental analysis, FT-IR and electronic spectroscopy (UV-Vis) and single-crystal X-ray diffraction (XRD) techniques. The thermal degradation of the Ni(II) complex was investigated using thermogravimetric and differential thermal analyses techniques in oxygen atmosphere. The molecular structure of the complex was determined by single crystal X-ray diffraction technique. Hirshfeld surface analysis (HSA) investigated the packing modes and intermolecular interactions in molecular crystals, as they provide a visual picture of intermolecular interactions. In addition, all computational studies at B3LYP/6-311++G(d,p) were carried out for theoretical characterization of Ni(II) complex. The optimized geometry results, which were well represented the X-ray data, were shown that the chosen of DFT/B3LYP/6-311++G(d,p) was a successful choice for title compound. After a successful optimization, FMOs, chemical activity, non-linear optical properties (NLO), molecular electrostatic potential (MEP), Mulliken population (MPA), natural population analyses (NPA), Fukui function analysis (FFA) and natural bond orbital analysis (NBO), which could not obtained by experimental ways, were calculated and investigated. The computed of net charges and chemical activity studies which helped to identifying the electrophilic/nucleophilic nature.     

Crystal structure of p-formylphenyl, di(p-methylphenyl)amine, and p-bromophenyl, di(o-bromo-p-methylphenyl)amine

p-Formylphenyl, di(p-methylphenyl)amine (1), and p-bromophenyl, di(o-bromo-p-methylphenyl)amine (2) were prepared and characterized by X-ray crystallography. Formyl-substituted triphenylamine(1) crystallizes in the monoclinic space group P2₁/c with a = 9.068(1), b = 17.115(2), c = 11.297(2) Å, = 106.73(1)°, V = 1679.0(5) ų and Z = 4. Bromo-substituted compound 2 crystallizes in the monoclinic space group P2₁/n with a = 16.170(4), b = 7.9477(8), c = 16.906(4) Å, = 117.67(2)°, V = 1924.1(7) ų and Z = 4. The N atoms deviate slightly from the plane of the bonded C atoms and the benzene ring planes are rotated by 25–67° to avoid overlap of the ortho-substituted atoms. The major force of crystal formation comes from the multiple phenyl embraces (MPE).     

Preparation,properties, and crystal structure of bis(acetylcholine)tetrabromodioxouranium(VI)

The compound bis(acetylcholine)tetrabromodioxouranium(VI), [C₇H₁₆-NO₂]₂ UO₂ Br₄, has been prepared and its physicochemical properties studied. No influence of the uranyl-bromide system on the muscarinic conformation of acetylcholine in the adduct was inferred on the basis of biological activity measurements. This lack of effect on the acetylcholine molecule by [UO₂Br₄]^2– anion is confirmed by X-ray structure determination. The crystals are orthorhombic, space groupPnma,Z = 4,a =13.60(2),b = 20.94(3),c = 9.22(2) Å. The conventional discrepancy index is 0.087 for 1822 diffractometer data. Some disorder is observed in the acetylcholine molecule.Abbreviations AcCh Acetylcholine - [AcCh]₂UO₂Br₄ bis(acetylcholine)tetrabromodioxouranium(VI) - AcChE Acetylcholinesterase     

Synthesis,thermal, spectroscopic,and X-ray studies of (dichloroacetato)(triphenylphosphine)gold(I)

The synthesis, thermal, spectroscopic, and X-ray investigation of (dichloroacetato) (triphenylphosphine)gold(I), [Au(C₂HCl₂O₂)(C₆H₅)₃P] are reported. The thermal analysis showed that the decomposition of the studied complex is a two step process and the mechanism of the decomposition has been proposed. IR and¹³C NMR spectra of the complex are given. The compound crystallizes in the monoclinic space groupP2 ₁/n with four molecules per unit cell.M _r =587.19,a=11.455(1),b=12.398(3),c=14.718(2)Å,=104.95(1)°,V=2019.5(6)ų,D _x=1.931g/cm³,(Cu K)=172.6 cm^–1,F(000)=1120. FinalR=0.059 for 2780 absorption-corrected reflections. The crystals are not isostmctural with acetato(triphenylphosphine) gold(I) and (trifluoroacetato)-(triphenylphosphine)gold(I). The Au-O1 bond length is of 2.049(9), Au-P of 2.210(3)Å with O1-Au-P angle of 176.9(2)°.     

Synthesis, spectroscopic studies, and crystal structure of tris(tetra-n-butylammonium) hexakisisothiocyanatoindate(III)

The reaction of a 1:10 molar ratio between indium chloride and tetra-n-butylammonium thiocyanate in ethanol affords the complex [(n-C₄H₉)₄N]₃[In(NCS)₆] (1), the structure of which has been established by X-ray diffraction. This compound crystallizes in the cubic space group Pa3¯ with eight formula units in the unit cell. The formula unit consists of three separate cationic tetra-n-butylammonium groups and an independent hexakisisothiocyanatoindium anionic group. The six near linear thiocyanate ligands coordinate octahedrally through the nitrogen atom to the indium metal center. The coordination of the n-butyl groups to the ammonium-nitrogen atom is tetrahedral. The complex has also been characterized by IR, ¹H and ¹³C NMR, physical properties, and X-ray powder analysis.     

Platinum(II) dibromo,bis (3,5-diamino-1(2)-triazolium) dibromide: Synthesis,crystal and molecular structure,and infrared characterization

The title compound C₄H₁₂PtN₁₀Br₄ was prepared and characterized by means of X-ray, and IR measurements. The crystals are monoclinic, space groupP2₁/c, (C _2h ⁵ No. 14) witha=6.875(1),b=15.478(2),c=7.074(1)Å,=90.98(1) andZ=2. The structure was solved by the heavy-atom method, and least-squares refinement of structural parameters led to a conventionalR factor of 0.031 (R _w=0.030) for 733 independent reflections. The compound exhibits discrete monometallic units with the 1,2,4-triazolium ion acting as modentate ligand. The structure consists of centrosymmetric units in which the platinum atom is coordinated in perfectly planar geometry by two nitrogen and two bromine atoms. The NH and NH₂ group of the guanazolium unit are involved in intermolecular hydrogen bonds. Infrared bands are diagnostic of the coordination environments around the metal atoms.     

Crystal and molecular structure of bis(N,N-di-n-butyldithiocarbamato)gold(III) dibromoargentate(I)

The crystal and molecular structure of bis(N,N-di-n-butyldithiocarbamato)gold(III)dibromoargentate(I), Au(S₂CN(C₄H₉)₂)₂AgBr₂, has been determined by three-dimensional X-ray methods. The compound crystallizes in the monoclinic space groupC2/c with unit cell dimensions:a= 17·39(1)b = 18·65(1);c = 9·199(6) Å; = 93·9(1)°;Z=4. Intensities were collected on an automatic diffractometer. The structural parameters were refined by least-squares methods to a conventionalR factor of 0·048 for 854 non-zero observed reflexions. The structure consists of Au(S₂CN(C₄H₉)₂)2⁺ and AgBr₂ ^– ions. The gold is in planar coordination with four sulphur atoms, the two crystallographically non-equivalent Au-S bond lengths being 2·357(8) and 2·324(8) Å. The silver is linearly coordinated, the Ag-Br bond lengths being 2·450(5) Å. The ionic packing in the structure differs from that in the analogous Au(S₂CN(C₄H₉)₂)₂AuBr₂ complex.The authors are grateful to Professor J. J. Steggerda for his continuous interest and to Mr. W. P. J. Bosman and Mr J. M. M. Smits for valuable assistance. Authors of contributions from the Department of Inorganic Chemistry and Crystallography of this University will no longer be listed in alphabetical order.     

Crystal structure of 3,3-(p-N,N-dimethylaminophenyl)-6-N,N-dimethylaminophthalide, (crystal-violet lactone)

The title compound is C₂₆H₂₉N₃0₂,M _r ,=415.54, monoclinic,P2₁/n,a=12.228(1),b=17.385(2),c=11.786(1) Å,V _c =2308.7 Å₃,Z=4,D _x =1.19 Mg m^–3,=5.29 cm^–1,F(000)=888. FinalR=0.046 for 2301 independent reflections. Three cyrstallographically distinct nitrogens were found, with the molecule possessing the expected propeller shape.     

Structure of hexakis(imidazole)nickel(II) disalicylate, [Ni(Im)6](Sal)2

The crystal and molecular structures of [Ni(Im)₆](Sal)₂ (Im = imidazole, Sal = salicylate) have been determined by X-ray crystallography. It crystallizes in the triclinic system, space group P1¯, with lattice parameters a = 8.3125(2), b = 8.7168(1), c = 12.3262(3) Å, = 90.341(1), = 96.33(1), = 101.544(1)°, and Z = 1. The crystal structure of the title compound is built up of discrete monomeric molecules of [Ni(Im)₆](Sal)₂. The nickel(II) ions have an octahedral geometry with the NiN₆ chromophore. In the solid state, the title compound forms a network through N—H···O hydrogen bonds, the intermolecular hydrogen bonds connect the Ni(Im)²⁺ ₆ moieties and salicylate molecules.     

Structure,IR, and NMR spectra of tetrakis(4-methyl piperidinedithiocarbamate) dimercury(II)

The compound C₁₄H₂₄HgN₂S₄ was prepared and characterized by means of X-ray, IR, and NMR measurements. The crystals are monoclinic, space group P2₁/c, (No. 14) witha=8.697(2),b=19.156(3),c=12.098(2) Å,=108.14(1)° andZ=4. The structure was solved by the heavy-atom method, and least-squares refinement of structural parameters led to a conventionalR factor of 0.027 for 2469 independent reflections. The structure consists of discrete dimeric units with the metals coordinated to five sulphur atoms. The IR and NMR spectra are discussed on the basis of the known structure.     

Electronic properties and atomic structure of (Ti, Zr, Hf)---(Ni, Cu) metallic glasses

The available experimental and theoretical data on the electronic density of states at the Fermi level, n(E_F), of non-magnetic melt-quenched TE_100-xTL_x amorphous alloys (Te = Ti, Zr or Hf; TL = Ni or Cu) and for the corresponding crystalline counterparts is reviewed. First, the low-temperature specific heat and superconductive data are summarized, in order to derive experimental n(E_F) values. A comparison with n(E_F) data from theoretical band structure calculations shows good overall agreement, both qualitative and quantitative. By taking into account recent results on the different structural modifications of Ti, Zr and Hf metals, an extrapolation of the composition dependence of n(E_F) in TE-TL glasses to pure amorphous TE metals suggests that the local structure of these TE-TL amorphous alloys may be described by an fcc-like atomic arrangement. Some other reported results, which supply further evidence for the proposed fcc-like local structure in this type of metallic glass, are also discussed.     

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.