DC conduction in bis(dimethylglyoximato)palladium(II) thin films

Bis(dimethylglyoximato)palladium (II) complex thin films of polycrystalline structure were prepared by sublimation in a vacuum at 140°C on p‐Si substrates. After carrying out the characterisation of the prepared films by X‐ray diffraction and X‐ray fluorescence methods, Al‐complex‐Si MIS devices were fabricated. The constructed MIS structure was characterised by measuring the capacitance as a function of gate voltage at 1 MHz. The dependence of dc‐current density on gate voltage and temperature in the range of 293 ‐ 328 K of the MIS device was measured. It was found that the experimental data follow the trap‐charge‐limited space‐charge‐limited conductivity mechanism, from which the total concentration and the exponential energy distribution of the trap density were determined. In general, the measured quantities suggest that the conduction can be realised by thermally assisted hopping between localised states bundled in a very narrow band lying energetically near the mobility band edge. Moreover, results show that it is possible to use a film of the complex in applications of low‐k dielectric material. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal and molecular structure of bis(N,N-diethyldithiocarbamato)palladium(II)

The crystal and molecular structure of bis(N,N-diethyldithiocarbamato)palladium(II), Pd(S₂CN(C₂H₅)₂)₂, has been determined by a three-dimensional X-ray analysis. The compound crystallizes in the tetragonal space groupP4₂/n with unit cell dimensionsa = 16·439(8) Å andc = 6·247(3) Å. The crystals are isomorphous with bis(N,N-diethyldithiocarbamato)platinum(II). Intensities were obtained with an automatic diffractometer. The structural parameters were refined by least-squares methods to a conventionalR factor of 0·038 for 600 non-zero observed reflections. The palladium is in planar coordination with four sulphur atoms, the two non-equivalent Pd-S bond lengths being 2·317(3) and 2·315(3) Å.The authors are grateful to Mr J. G. M. van Rens for providing the crystals and measuring the unit cell dimensions, to Professor J.J. Steggerda for his continuous interest and to Mr W.P.J.H. Bosman, Mr J.M.M. Smits and Mr J.A.B.C. Wolf for valuable assistance.     

Synthesis and Structure of Trans‐bis(ethanolamine)bis(saccharinato)mercury(II)

Trans‐bis(ethanolamine)bis(saccharinato)mercury(II), [Hg(ea)₂(sac)₂], where ea and sac denote the ethanolamine molecule and the saccharinate anion, respectively, crystallizes in the triclinic space group P (No. 2) with a = 9.4651 (5), b = 10.4365 (5), c = 11.9314 (6) Å, α = 84.402 (1)° β = 78.313 (1)°, γ = 75.307 (1)°, Z = 2, V = 1115.11 (10) ų. The structure consists of isolated [Hg(ea)₂(sac)₂] units in which the Hg(II) ion is octahedrally coordinated by two nitrogen and two oxygen atoms of two neutral ea ligands, and two nitrogen atoms of two sac ligands. The ea acts as a bidentate N‐ and O‐donor ligand and occupies the trans positions of the equatorial plane of the coordination octahedron forming a fivemembered chelate ring, while sac behaves as a monodentate N‐donor ligand occupying the axial positions. The average Hg‐N_sac and Hg‐N_ea bond distances are 2.739 (3) and 2.114 (7) Å, respectively. The crystal exhibits extensive hydrogen bonds between the hydroxyl and amine hydrogen atoms of the ea ligands and the sulfonyl, carbonyl and amine groups of the sac ligands.     

Synthetic and structural studies of the trans bis(2-N-H-pyrrolylcarbaldimine) complexes of nickel(II) and palladium(II)

The molecular bis(2-N-H-pyrrolylcarbaldimine)nickel(II) and palladium(II) complexes are isolated in moderate yield (30–35%) from in situ assembly of the Schiff base with metal(II) salt, base, and pyrrole-2-carbaldehyde in aqueous ammonia solution. The nickel(II) complex, 1, is monoclinic, space group P2₁/c, with a=11.289(6) ?, b=5.611(3) ?, c=8.287(5) ?, β=111.620(6)°, and V=488.0(5) ?³ with Z=2, for d _calc=1.667 Mg/m³. The palladium analog, 2, is isomorphous, space group P2₁/c, with a=11.481(3) ?, b=5.5738(10) ?, c=8.276(2) ?, β=110.923(12)°, and V=494.7(2) ?³ with Z=2, for d _calc=1.965 Mg/m³. In both crystal structures, the metal resides on an inversion center. In the IR spectra, ν(C=N) appears at 1561 cm⁻¹ in 1, and 1557 cm⁻¹ in 2, while ν(N–H) shows at 3345 cm⁻¹ and 3335 cm⁻¹, respectively. The ¹H-nmr spectra reveal the C–H and N–H protons of the imine group as sharp and broad doublets, respectively, at 7.62 and 8.38 δ in 1 and at 7.92 and 9.73 δ in 2.     

Crystal structure of bis(benzimidazolium) tetrabromocuprate(II)

Stable, dark-violet crystals of (C₇H₇N₂)₂CuBr₄ were obtained from an aqueous solution of CuBr₂, HBr, and benzimidazole. The crystal structure was determined by three-dimensional X-ray analysis. The crystals are monoclinic:C2/c, a=15.651(4),b=7.945(1),c=15.775(4) Å,=91.44(2)°,Z=4,V _c=1960.96 ų,D _x=2.105 g cm^–3. The structure was refined by full-matrix least squares to giveR=0.042 andR _w=0.048 for 1254 intensities above 3(I). The copper(II) ions are four-coordinated in the form of a distorted tetrahedron CuBr₄ ofC ₂ symmetry. Two different Cu-Br bond lengths are observed: Cu-Br(1)=2.426(2), Cu-Br(2)=2.330(2) Å. Only one flattened angle [Br(2)-Cu-Br(2)=132.71(9)°] in the CuBr₄ tetrahedron is noted. The angles Br(1)-Cu-Br(1)=108.83(7), Br(2)-Cu-Br(1)=99.92(5) and Br(2)-Cu-Br(1)=107.13(5)° have been found. Hydrogen bonds explain the deformation of the CuBr ₄ ^2– coordination polyhedron. The structure is compared with other CuX ₄ ^2– complexes.     

Crystal and molecular structure of bis(tetrathiafulvalene) bis(maleonitrile-1,2-dithiolato)nickelate(II)

The crystal and molecular structure of the title compound, C₂₀H₈N₄S₁₂Ni, is reported. Crystals are triclinic, space groupP¯1 (No. 2) withz=1 in a cell of dimensionsa=8;482(2),b=7.950(2),c=9.976(2) Å,=95.64(2),=98.60(2), and =87.65(2)°. The structure was solved by Fourier methods and refined by the method of least squares toR=0.033 for 2027 unique reflections. The Ni atom has an approximate square-planar configuration with Ni-S(1)=2.179(1), Ni-S(2)=2.175(1) Å, and the S(1)-Ni-S(2) bite angle of 91.89(4)°. The anions and the cations form a mixed stack (DAD-DAD-) along the diagonal of theab plane, showing the possibility of unusual electrical behavior.     

Crystal and molecular structure of bis(tetramethyl-ammonium)bis(maleonitriledithiolato)cuprate(II). Structure of C16H24CuN6S4

The crystal and molecular structure of the title compound, C₁₆H₂₄CuN₆S₄, is reported. The crystals are monoclinic: space groupP2₁/c,Z=4,a=13.230(3),b=11.518(9),c=16.269(6) Å,=95.07(2)°. The structure was solved by the heavy-atom method, and refined by full-matrix least squares toR=0.059 for 1907 unique diffractometer data. The anions have approximately 222 (D ₂) symmetry, with an angle of 41.14(1)° between the normals to planes of the ligands. The amino atoms of the cations have an approximate tetrahedral configuration. The anions are well separated from each other, the closest Cu-Cu distance being 7.811 (2) Å. The anionic units can be considered as being stacked alongb in columns. The metal atoms are not collinear along the stack axis, but form a kind of kinked chain.     

Structures of bis(N-n-butylsalicylideneiminato)cobalt(II) and bis(N-tert-butylsalicylideneiminato)cobalt(II) complexes and reactivity towards oxygen and nitric oxide

The cobalt(II)-Schiff base complexes [Co(nbsal)₂] and [Co(tbsal)₂] [nbsal=N-n-butylsalicylideneiminate and tbsal=N-tert-butysalicylideneiminate,o-OC₆H₄CH=NR,R+Buⁿ and Bu^t, respectively] both have distorted tetrahedral structures, but the presence of thetert-butyl groups in [Co(tbsal)₂] causes much greater angular distortion, of the coordination tetrahedron. Although [Co(nbsal)₂] will react with nitric oxide and oxygen, [Co(tbsal)₂] reacts with neither and this appears to be due to the shielding of the cobalt by thetert-vutyl groups. The reactive complex [Co(nbsal)₂] crystallizes in the tetragonal system,a+14.244,c+5.395, Å,Z+2 and space group $P\bar 4$ . The structure was determined by the heavy-atom method, using MoKα diffractometer data, and refined by full matrix least-squares toR+0.035 for 777 reflections. The unreactive complex [Co(tbsal)₂] crystallizes in the orthorhombic systemPbc2₁,a+10.977,b+20.037,c+9.866 Å,Z+4. The structure was determined as above toR+0.051 for 1458 reflections.     

Crystal structure of bis(4-dimethylaminopyridinium) tribromocuprate(I) and bis(4-dimethylaminopyridinium) tetrabromocuprate(II)

The synthesis and crystal structures of two copper bromide salts of the 4-dimethylaminopyridinium (4DMAP⁺) cation are reported. The Cu(I) salt, (4DMAP)₂CuBr₃, crystallizes in the monoclinic space group C2/c, with a = 11.724(2), b = 11.055(3), c = 15.763(3) Å, = 107.64(3)°, and Z = 4. It contains isolated planar 4DMAP⁺ cations and trigonal planar CuBr₃ ^2– anions. Small distortions from idealized D _3h symmetry are observed for the anion. For the Cu(II) salt, (4DMAP)₂CuBr₄, a triclinic cell is observed with a = 8.2373(2), b = 9.2428(2), c = 14.4391(1) Å, = 93.760(1), = 94.576(1), = 105.249(1)°, and Z = 2. This compound contains discrete planar 4DMAP⁺ cations and flattened tetrahedral CuBr₄ ^2– anions. Small distortions are observed for ideal D _2d symmetry.     

Crystal and molecular structure oftrans-dichlorobis(oxazole)palladium(II)

The crystal and molecular structure oftrans-dichlorobis(oxazole)palladium-(II), Pd(C₃H₃ON)₂Cl₂, has been determined by single-crystal X-ray diffraction techniques using counter methods and has been refined by full-matrix least-squares procedures to a finalR index of 0.022. The complex crystallizes in the triclinic space groupP¯1 with unit cell dimensions ofa = 6.957(1),b = 7.506(1),c = 5.538(1) Å, = 109.22(1), = 91.37(1), and = 115.09(1) °, withZ = 1. The palladium(II) ion, located at an inversion center, is coordinated in a regular square-planar manner to two chloride ions at 2.293(1) Å and, at 2.016(2) Å, to the nitrogen atoms of two oxazole ligands. The planar oxazole rings are tilted 33 ° with respect to the PdN₂Cl₂ plane. Further verification of the presence of oxazole in the complex was obtained by high-resolution mass spectrometry. Crystals of Pd(C₃H₃ON)₂Cl₂ resulted irreproducibly from attempts to prepare single crystals of a previously reported dimeric palladium(II) disulfide complex by treating Pd(CH₃CN)₂Cl₂ with a slight excess of diphenyl disulfide in benzene in the atmosphere. The source of the oxazole is not understood.     

Crystal and molecular structure oftrans-dichlorobis(N-propylimidazole)palladium(II)

The crystal structure of Pd(N-PropIm)₂Cl₂ has been determined from X-ray data collected by counter methods. The compound crystallizes in the monoclinic space groupP2₁/n with four molecules per unit cell, the dimensions of which area=14.554(5),b=8.204(2),c=14.860(3) Å,=115.63(2)°. Full-matrix least-squares refinement gave a final R value of 0.0263 for 1913 independent observed reflections. The Pd atom is four-coordinated and is surrounded in atrans square planar fashion by two N atoms of the imidazole groups and by two Cl ions.     

X-ray crystal structure oftrans-dichlorobis(2,6-lutidine)palladium(II)

The X-ray structure oftrans-(2,6-lutidine)₂PdCl₂ has been determined. Golden orange crystals of the complex crystallize in the triclinic space group , with cell dimensionsa=7.6950(8),b=7.9705(10),c=8.0485(8)Å, =116.967(9), =113.343(8), and =93.836(9)°;V=385.18(7)ų andZ=2. 1336 unique reflections withI _net>3 (I) on refinement afforded values ofR=0.018 andR _w=0.023.     

Synthesis and structure of bis(dibenzoylmethane)copper(II)

Bis(dibenzoylmethane)copper Cu(dbm)₂ has been synthesized and its structure determined by x-ray diffraction. It crystallizes in the monoclinic system, space group C2/c, with a = 25.936(3), b = 5.9806(8), c = 16.4908(16) Å, = 114.998(8)°, Z = 4, and V = 2318.3(4) ų. The Cu atom is located at a symmetry center and surrounded by four O atoms from two dbm molecules to form a plane square coordination environment. On the a–c plane the molecules are orderly arranged to result in a layered structure, and parallel to crystallographic b-axis they form a molecular column due to the effect of aromatic stacking.     

Crystal structure of bis(2,4-pentanedionato)copper(II)

The structure of bis(acetylacetonato)copper(II) has been redetermined from single crystal X-ray diffraction data. The unit cell parameters area=11.331(9),b=4.697(3),c=10.290(9) Å, and=91.84(7)dg. A finalR=0.056 for 727 observed reflections was obtained. The O-Cu-O chelate (bite) angle is 93.2(2)°. The two Cu-O bond lengths are 1.914(4) and 1.912(4) Å. The complex has a slight chair structure and a step angle of 7.05°.     

Structure of dichloroethanolaminecopper(II) and dibromoethanolaminecopper(II)

CuCl₂(NH₂CH₂CH₂OH) is monoclinic, space group C2/c, witha+11.092(2),b+10.012(2),c+6.401(1) Å, =121.71(1)°, andV=604.8(2)ų withZ+4. The structure was refined to a final value ofR+0.27 for 518 unique observed reflections with |F|>3. The ethanolamine and halide ions coordinate to the copper(II) ion forming a pseudoplanar four-coordinate monomeric CuCl₂L² complex (L²+bidentate ligand). The copper ion also interacts with the halides of neighboring complexes through the formation of semi-coordinate Cu-Cl linkages (2.926(1) Å) between oligomers. The copper thus attains a 4+2 elongated octahedral coordination geometry. In this space group, the ligand is statisticallydisordered The Cu-Cl distance is 2.267(1)Å while the Cu-N/O distances are 2.025(2)Å. The dibromide structure is isomorphous with the dichloride structure, with space group C2/c, anda+11.285(2),b+10.218(2),c+6.715(1) Å, =121.65(1)°, andV=659.2(2)ų.     

Structure and characterization of bis(N-p-chloro-phenyl-salicylideneaminate) Schiff base copper(II) complex: Cu[N-p-Cl-Ph-Sal]2

The crystal and molecular structure of the title compound has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group P2₁/c, with lattice parameters a = 13.678(3), b = 10.729(2), c = 8.1996(2) Å, = 98.96°, V = 1188.7(4) ų, and Z = 4. The crystal structure contains two centrosymmetric molecules of bis (N-p-chloro-phenyl-salicylideneaminate) Schiff base copper(II). Copper(II) ion is coordinated in a slightly distorted trans square-planar configuration, the distortion consisting of a reduction of the N–Cu–O angle with the chelate rings from the ideal value of 90°. The p-chlorophenyl rings with salicylidene moieties form a dihedral angle of 38.96°.     

Synthesis and crystal structure of bis(benzimidazolium) tetrahalocobaltate(II)

The crystal structures of benzimidazolium tetrahalocobaltates (HBz)₂[CoX₄] (X = Cl and Br) have been determined. The chloride salt is triclinic, P-1, with a = 7.670(3) Å, b = 8.307(3) Å, c = 15.730(2) Å, and = 87.37(3)°, = 84.99(3)°, = 67.72(2)°. The bromide salt is monoclinic, C2/c, with a = 15.568(2) Å, b = 8.063(3) Å, c = 5.762(2) Å and = 91.36(3)°. The structures of the two salts are closely related. Both the compounds contain isolated tetrahedral CoX₄ ^2– anions and benzimidazolium cations. In the chloride salt, three chloride ions are involved in strong hydrogen bonding while only two bromide ions participate in the bromide salt. The greater deviation from the ideal tetrahedral geometry in CoBr₄ ^2– can be related to the less extensive hydrogen-bonding network compared to the chloro complex.     

Crystal and molecular structure of bis(aminomethylphosphonate)copper(II)

The crystal and molecular structure of bis(aminomethylphosphonate)-copper(II), C₂H₁₀N₂O₆P₂Cu, has been determined from MoK diffractometer data. The compound crystallizes in the monoclinic space groupP2₁/n witha =7.571(2),b = 4.943(1),c = 11.212(3) Å, = 105.84(2) °, andZ = 2. The structure was solved by the heavy-atom technique and refined by full-matrix least-squares methods toR = 0.041, using 1084 reflections for which ¦F _o¦ > 3.92 (¦F _o¦). In this complex, the Cu atom is square-planar coordinated by four O atoms from four phosphonic groups, and not by the amino group. The Cu-O bond lengths are 1.928(3) and 1.937(3) Å, and the phosphonic groups bridge adjacent Cu atoms in polymeric chains. The infrared spectrum of this complex is reported.     

Structure of bis(dipropyldithiocarbamate) cadmium(II), [Cd2(n-Pr2dtc)4] (dtc = dithiocarbamate)

The cadmium complex of bis(dipropyldithiocarbamate), [Cd₂(n-Pr₂dtc)₄] (dtc = dithiocarbamate) was crystallized from ethylether. It crystallizes in the monoclinic system, space group P _2I/c, with lattice parameters, a = 8.2532(1), b = 19.4519(1), c = 13.4163(2) Å, = 99.243(1)°, and Z = 4. The X-ray single-crystal structure of [Cd₂(n-Pr₂dtc)₄] reveals that the complex is binuclear in the solid state and the Cd atom has a distorted square-pyramidal coordination environment and four equatorial donors are the two bidentate chelate sulfur atoms from two dtc ligands, of which the sulfur atom from the bridging dtc ligand occupies the apical position of the symmetry-related Cd atom in the dimer structure.