Influence of proton implantation on the properties of CuInSe2 single crystals (II)

Copper deficient p-type conducting CuInSe₂ single crystals were implanted with 40 keV protons in the fluence range from 2.5 · 10¹⁴ to 1.5 · 10¹⁶ cm⁻². Over the whole fluence range the implanted layers were n-type conducting which is ascribed to passivation of the acceptors due to copper vacancies and formation of donors by hydrogen atoms located at interstitial positions. The thermal stability of the conductivity changes due to proton implantation is limited to temperatures below 100 °C.     

Structure and properties of cobalt(II) complex with a tetraaza macrocycle containing 2-pyridylmethyl pendant arms

The complex [Co(L)]Cl₂·10H²O (1) (L = 2,13,-bis(2-pyridylmethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,0^1.18,0^7.12]docosane) has been synthesized and structurally characterized. Compound 1 crystallizes in the triclinic system, space group P-1 with a = 9.731(2) Å, b = 9.789(2) Å, c = 11.998(1) Å, = 66.66(1)°, = 76.95(1)°, = 87.99(2)°, V = 1020.4(3) ų, and Z = 1. The crystal structure of 1 shows that the complex is centrosymmetric and the cobalt(II) ion has a slightly distorted octahedral geometry with four nitrogen atoms of the macrocycle and two nitrogen atoms of the pendent arms at the axial positions. Cyclic voltammetry for 1 undergoes reversible one-electron oxidation to the Co(III) and irreversible one-electron reduction to the Co(I).     

Crystal structure and physical properties of a ruthenium(II) bipyridine dimethylsulfoxide complex

The complex [Ru(bpy)₂(DMSO)C1]PF₆, where bpy is 2,2-bipyridine and DMSO is dimethylsulfoxide, crystallizes in the triclinic space group P1¯ (#2) with a = 8.873 (2), b = 12.805 (4), c = 12.864 (4) Å, = 97.76(3), = 106.45(2), = 107.88(2); Z = 2, and d _calc = 1.75 mg/m³. The coordination geometry is that of a distorted octahedron with a cis –RuN₄SCl arrangement of coordinating atoms. The four Ru—N distances to the bpy ligands are 2.082(5), 2.092(4), 2.044(4), and 2.078(5) Å. The Ru—Cl distance is 2.421(2) Å and the Ru—S distance to DMSO is 2.260(1) Å. The Ru—N bond distance trans to Cl is the shortest; the Ru—N bond distance trans to S is the longest. The complex is oxidized and reduced reversibly at 1.13 and –1.37 V vs. SSCE, respectively. It displays electronic absorptions at 515, 480 (1.5 × 10⁴), 342 (1.5 × 10⁴), 292 (1.2 × 10⁵), and 240 nm (6.2 × 10⁴) and has a broad emission band centered at 607 nm at 77 K in a 4:1 ethanol/methanol glass. The emission lifetime at room temperature is less than the pulse width of the laser, < 20 ns.     

Effective oxygen charge in SiO2 and its dependence on the bond angle of oxygen

It is not clear until now, whether the oxygen bond angle and the effective oxygen charge in SiO₂ are correlated or not. This paper reviews various theoretical and experimental facts concerning some special features of the atomic structure and of electronic properties of SiO₂. They lead to contrary conclusions about the correlation between the effective oxygen charge and the oxygen bond angle in distinct SiO₂ forms. Results basing on quantum-chemical investigations are compared with conclusions drawn from the dielectric theory and from tight-binding calculations of electronic states. A critical valuation of the different methods with special consideration of solid-state investigations yield the result that the effective oxygen charge increases with increasing bond angle.     

Coordination properties of sulfonyl-N-aminoacids: Crystal and molecular structure of the [Zn(II) (N-(p-toluenesulfonyl)-L-glutaminate)2(H2O)2] complex

The coordination behavior of N-tosyl-L-glutamine (hereafter abbreviated as tsglnH, tosyl =toluenesulfonyl group) toward the Zn(II) ion is investigated by means of structural and spectroscopic techniques. From aqueous solution, at acidic pH the Zn(II) ion separates a compound of empirical formula Zn(tsgln)₂·2H₂O whose crystal structure is determined. The crystal is monoclinic, space group C2, with cell dimensions:a=19.775(5),b=5.3146(3),c=16.543(8) Å, =119.93(3)°,Z=2. The Zn(II) is tetrahedrally coordinated by two symmetry-related tsgln monoanions acting as monodentate carboxylate ligands and two symmetry related water molecules. The Zn–O bond distances are similar while the angles at Zn(II) ion differ significantly from those of regular tetrahedron. The side chain amide group does not participate in metal coordination and forms intermolecular hydrogen bonds.     

Influence of complex formation upon inclusion of Mn(II), Co(II), Ni(II), and Cu(II) in ZnC2O4·2H2O

The inclusion of 3d‐impurities Mn(II), Co(II), Ni(II) and Cu(II) in a crystalline precipitate of ZnC₂O₄·2H₂O is investigated. This study is a part of the systematic one deal with the mechanism of inclusion of 3d‐ions in sparingly soluble oxalate systems. The experiments are carried out in bi‐ end multi‐component systems at two different mediums – one with deficiency of oxalate ions, another with excess. The insertion of 3d‐ions upon mass crystallization of ZnC₂O₄·2H₂O does not proceed by a simple ionic substitution. The results show that the inserted amount of impurity depends on some physicochemical characteristics of the neutral monooxalato complexes [MnC₂O₄]^o, [CoC₂O₄]^o, [NiC₂O₄]^o and [CuC₂O₄]^o. Good agreement between included impurity and the concentration of its complex in the solution is established. The stability constant of monooxalato complex affects the impurity inclusion. This effect depends on the medium nature. In the deficiency of oxalate ions the factor determining the inclusion is thermodynamic one – stability of monooxalato complexes. In the excess of oxalate ions inserted amount depends on kinetic factor – the formation rate of these complexes. In the term of that the insertion of Mn(II) is definitely different in the two mediums while that of the Ni (II) does not depend on the medium. The copper shows deviation from overall dependence in the two mediums due to the Jahn‐Teller distortion. Its double decreasing insertion in the excess of oxalate ions is related with stabilization of [Cu(C₂O₄)2]^2‐. The conclusions presume that by varying the background medium and taking in view the ions present in the solution, the amount of inserted impurities can be predicted and controlled. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The crystal structure of a N-(2-thiophenyl)-salicylaldiminopiperidino nickel(II) complex

The crystal and molecular structure of the title complex, C₁₈H₁₉N₂OSNi, has been determined by direct methods. The compound crystallizes in monoclinic crystal system witha=11.968(1),b=12.182(1),c=12.399(1) Å, =115.23(1)°, space group P2₁/n. Nickel is in a slightly distorted square-planar environment of two nitrogens [1.881(2) and 1.952(2) Å] and one oxygen [1.856(3) Å] and one sulphur [2.138(2) Å] atom. Ni is 0.005 Å out of the plane of its ligands.     

Structural characterization of the edge double-bridged triruthenium cluster complex Ru3(μ-Cl)2(CO)8(PPh3)2

The title compound is Ru₃(-Cl)₂(CO)₈(PPh₃)2. Crystal data: formula C₄₄H₃₀O₈Cl2P2Ru₃;f _w =1122.9; monoclinic,P2₁; cell parameters (at 293 K)a=10.971(2) Å,b=17.066(2) Å,c=11.833(2) Å,=92.91(1)°,V=2213 ų,Z=2, _calcd=1.68, _meas=1.68. Final discrepancy indices areR(F)=0.030,R _W (F)=0.036. The structure consists of an open trinuclear unit involving two metal-metal bonds [Ru(1)-Ru(2)=2.845(1) Å, Ru(2)-Ru(3)=2.860(1) Å]. The open edge of the metal framework [Ru(1)Ru(3)=3.254(1) Å] is supported by two symmetric bridging chloride ligands [Cl(1)-Ru(1)=2.461(2) Å; Cl(1)-Ru(3)=2.464(2) Å; Cl(2)-Ru(1)=2.470(2) Å; Cl(2)-Ru(3)=2.472(2) Å]. Both phosphorus ligands are cis to the Cl atoms and trans to the unique ruthenium atom Ru(2). Geometric features of the edge dibridged complex are discussed.     

Structure and morphology of oxide deposition on SiO2 (I) correlations between parameters of layer formation and structure

The oxides of Ge, Sn and Ti were produced by reaction of the adequate metal tetrachlorides in dependence on reaction parameters (pressure, temperature, time) on crystalline and non-crystalline SiO₂ substrates. Structure and morphology of the formed oxides were investigated by electron diffraction and electron microscopy. In dependence on the reaction conditions results on the degree of crystallisation and on the particle size distribution could be received. On the basis of the obtained results of investigations conceptions for the mechanism of layer formation were derived.     

Crystal structure,physical, and photophysical properties of a ruthenium(II) bipyridine diazafluorenone complex

The complex [Ru(bpy)₂(dafo)](PF₆)₂, where bpy is 2,2-bipyridine and dafo is diazafluorenone crystallizes in the space group P2₁/n witha=9.505(3) Å,b=14.002(4) Å andc=25.783(8) Å. The coordination geometry of the Ru atom is that of a distorted octahedron with a RuN₆ core. The two Ru-N bond distances to the dafo ligand are 2.13(1) and 2.15(1) Å; the four Ru-N bond distances to the bipyridine ligands are 2.03(1), 2.05(1), 2.06(1), and 2.07(1) Å. The three shortest Ru-N distances aretrans to the three longest Ru-N distances. The complex is oxidized and reduced reversibly at 1.41 and –0.65 V vs. SSCE, respectively. It displays absorptions at 438 nm (1.6×10⁴), 285 nm (6.2×10⁴), and 240 nm (4.1×10⁴) and a broad emission centered at 626 nm in water at room temperature. The emission lifetime is 420 ns and the emission quantum yield is 5.3×10^–4.     

Crystal and molecular structure of a cobalt(II) complex with bis(benzimidazol-2-ylmethyl)-methylamine (L)

The reaction product of Co(II) chloride and the title ligand L, formulated as CoLCl₂·CH₃OH, was prepared and characterized by means of structural and spectroscopic measurements. The violet crystals are orthorhombic, (space groupP2₁2₁2₁) witha=8.093(2),b=14.883(3),c=16.831(3) Å, andZ=4. The structure consists of discrete molecules with pseudo-, noncrystallographic twofold symmetry in which the Co atom is coordinated in trigonal bipyramidal geometry by three nitrogen and two chlorine atoms. The ligand L is coordinated to the Co atom in afac mode and two chlorine atoms are incis-positions. The structure was confirmed by IR-spectra.     

Crystal and molecular structure of 2-(2-pyridyl)-indandione-1,3 and a zinc(II) complex with this ligand

The crystal structures of 2-(2-pyridyl)-indandione-1,3 C₁₄H₉NO₂ (HL, I) and the zinc complex ZnL ₂(Dmso) (II) (where Dmso is dimethyl sulfoxide) with this ligand are determined. The specific features of the crystal structures of both compounds are considered. A comparative analysis of the supramolecular aggregates in crystals of these compounds is performed. It is demonstrated that the supramolecular dimers retain their structure in the crystals of compounds I and II. These dimers are involved in weak secondary interactions (usually of one type) with the formation of spatially more complex supramolecular associates, such as chains, ribbons, and layers.     

Structural characterization and photophysical properties of a luminescent trinuclear zinc(II) complex exhibiting multiple coordination geometries

A luminescent trinuclear zinc(II) complex, tris(-2,3-toluenedithiolato)-1:2²S¹;1:2²S¹, 2:3²S²;3S², 1:3²S³;3S³-bis(2,2-bypyridine)-1²N,N,2²N,N-trizinc, containing 3,4-dimercaptotoluene (tdt) and 2,2-bipyridine (bpy) has been synthesized and found to have the trinuclear formulation Zn₃(tdt)₃(bpy)₂ (I). The complex crystallizes in the monoclinic space group P2₁/n with a = 11.7247(12), b = 20.134(2), c = 17.7376(18) Å and = 103.743(2). The complex has two heteroleptic zinc(II) centers exhibiting similar distorted trigonal bipyramidal geometries with the third homoleptic zinc(II) center displaying a flattened tetrahedral geometry. Present in the solid state are both intra- and intermolecular – interactions. The complex is emissive at 77 K in the solid state with an emission maximum at 574± 2 nm with a luminescence lifetime of 7.4± 0.4 ns. The unstructured emission is assigned as a metal-mediated ligand-to-ligand –^* charge transfer transition.     

Synthesis and structural characterization of the dinuclear tetrakis(guanidino) bis(2-cyanoguanidine)dicopper(II) complex

The synthesis and crystal structure of a new dinuclear complex Cu₂(C₂H₄N₄)₂ (CH₃N₃)₄ are reported. It crystallizes in the monoclinic system of space group P2₁/c, with a = 8,459(1) Å, b = 15,481(3) Å, c = 8,714(2) Å, = 110,60(1)°, and Z = 2. The centrosymmetric molecular structure of Cu₂(C₂H₄N₄)₂(CH₃N₃)₄ comprises a tetrakis(guanidino)-bridged dinuclear copper(II) core with axially located cnge moities.     

Fluorescence enhancement of europium complex co-doped with terbium complex in a poly(methyl methacrylate) matrix

The enhanced fluorescence of Eu(DBM)₃Phen(DBM: dibenzoylmethide; Phen: phenanthroline) by Tb(DBM)₃Phen in a poly(methyl methacrylate) (PMMA) has been studied. A combinatorial methodology was adopted to allow rapid optimization of the fluorescence enhancement conditions of thin-film samples in arrays of microwells. Based on Eu(DBM)₃Phen doped PMMA, three material libraries were generated in order to compare the effects of species identity and Tb(DBM)₃Phen content to the effect of other complexes containing enhancing ions (La³⁺, Gd³⁺, Dy³⁺, Y³⁺, Ce³⁺) on the luminescence efficiency of the Eu³⁺ complex in PMMA. The fluorescence enhancement of Eu(DBM)₃Phen in PMMA is considered to originate from intramolecular and intermolecular energy transfer processes.     

Crystal structure,physical and photophysical properties of a platinum(II) complex coordinated to the biphenyl dianion and cyclooctadiene

The complex, Pt(bph)(COD), where bph is the biphenyl dianion and COD is 1,5-cyclooctadiene, crystallizes in the orthorhombic space groupPbca witha=12.178(4) Å,b=9.693(3) Å andc=25.344(9) Å andZ=8. The Pt–C distances to the olefinic carbon atoms that result from the electron donation of the COD ligand are in the range 2.20(3)–2.27(3) Å and the Pt–C distances to the bonded bph ligand are shorter at 2.01(3)–2.03(2) Å. The lowest energy absorption of the complex is at 383 nm (=1.2×10³). The emission spectrum is structured in fluid solution at room temperature with the emission energy maximum at 537 nm, _cm, and =1.93 s. Temperature dependent emission lifetime measurements result in ak _o value of 2.69×10⁴, a preexponential factor of 2.47×10⁶ and a E₁ value of 324 cm^–1.     

Structural and magnetic properties of a syn-anti carboxylate bridged one-dimensional copper(II) complex with ferromagnetic exchange interaction

The compound [Cu(phen)(O₂CCF₃)₂]_n (phen = 1,10-phenanthroline) has been synthesized and its crystal structure determined. It crystallizes in monoclinic space group C2/c, with a = 19.229(7), b = 11.281(5), c = 7.621(2) Å, = 104.305(12)°, and Z = 4. The crystal structure is polymeric, being built from infinite zigzag chains of trifluoroacetate bridged copper(II), with the phenanthroline ligands being stacked between the chains. The variable-temperature (13–300 K) magnetic susceptibility and ESR data are reported and a weak ferromagnetic exchange interaction is observed with the exchange parameter estimated as J = 2.9 cm^–1.     

Synthesis,characterization and crystal structure of a novel 2D Ni(II) complex with malate

An exploration of the nickel‐ malate‐bpa system under hydrothermal conditions, has led to the isolation of a novel framework {[Ni(Hmal)(bpa)]·2.5H₂O}_n ( 1 ) (Hmal = malate dianion, bpa = 1,2‐bi(4‐pyridyl)ethane). Single‐crystal X‐ray analyses reveal that it crystallizes in the orthorhombic space group Fdd2. a = 21.9944(13) Å, b =33.3369(19) Å, c = 10.3969(5) Å, β = 90°. The Ni^II ions are linked into an extended helical chain via Hmal molecules. Further these chains are united together through the bridging bpa to form a 2D grid layer, which exhibits a typical (6,3) topological network. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)