Conducting Systems with Crystalline Ct Complexes

The method of reticulate doping previously used to obtain bulk-conducting macromolecular films is modified to yield surface-conducting materials. Morphology and properties of these systems, consisting of a conducting network of CT complex crystallites penetrating the bulk of an inert polymer matrix are briefly described, most of them being supposed to be common for bulk and surface-conducting films. Preparation of surface conducting films is discussed in terms of crystallization of the components of the CT complex initially molecular ly dispersed in the matrix due to a controlled increase of the molecular mobility in the surface layer of the film. Possible mechanisms responsible for the unusual effectiveness of the reticulate doping are discussed.     

Complexes of silicon tetrabromide with pyridine and 3,5-dimethylpyridine

The crystal structures of trans-tetrabromobis(pyridine)silicon (1) and trans-tetrabromobis(3,5-dimethylpyridine)silicon (2) have been determined: (1) crystallizes in the monoclinic space group C2/m with cell dimensions a = 14.4250(2) Å, b = 7.3055(1) Å, c = 7.2839(1) Å, = 117.660(1)°, (2) crystallizes in the monoclinic space group C2/m with cell dimensions a = 16.013(3) Å, b = 7.316(1) Å, c = 8.179(2) Å, = 113.19(1)°. Both molecules, with D_2h symmetry, have crystallographic C_2h site symmetry. The environment about the Si atoms can be described as a slightly distorted octahedron with the pyridyl ligands occupying axial positions and the four bromo ligands in the equatorial plane.     

Complexes with Hg(II) and macrocyclic ligands

The crystal structures of 1,4,7,10,13,16-hexaoxa-cyclooctadecane dicyano mercury(II) monohydrate, C₁₄H₂₄HgN₂O₆·H₂O, 1, and 2,5,8,11,18,21,24,27-octaoxa-tricyclo[26.4.0.0_12,17]-dotriconta-1(28),12,14,16,29,31-hexaene dicyano mercury(II) monohydrate, C₂₆H₃₂HgN₂O₈·H₂O, 2, were determined: 1 crystallizes in the trigonal space group R3¯ with cell dimensions a = 11.7842(1) and c = 12.0316(1) Å. 2 crystallizes in the monoclinic space group P2₁/c with cell dimensions a = 11.156(3) Å, b = 8.417(2), c = 30.901(8) Å, and = 93.279°. In spite of the different cyclic systems, similar complexes are formed where the Hg atom is coordinated by two CN groups and six oxygen atoms of the crown ether. The structure of 1 is isostructural with the crystal structures of 18C6—HgCl₂, 18C6—CdBr₂, 18C6—Sr(BH₄)₂, and 18C6—Ba(BH₄)₂. Furthermore, 1 is very similar to other 18C6—HgX₂ complexes.     

Synthesis and Structure of Uranyl Succinate Complexes with Cyanoguanidine and Diethylacetamide

Crystallography Reports - [UO2(suc)(C2N4H4)2] · 2H2O (I) and [UO2(Deaa)4(H2О)][(UO2)2(C4H4O4)3] · 2Deaa (II) crystals (suc2– is succinate ion, C2N4H4 is cyanoguanidine, and...     

Intelligent Sugar Complexes

Abstract

The structure of [Co(L-Rha)₃-mn)]Br₂.2CH₃OH, where (Rhah-tren is tris(N-rhamnosyl-2-aminoethyl)amine, was elucidated by X-ray crystallography, which confirmed the unprecedented configurational inversion of [Co((Rha)₃-tren)]²⁺, around the metal center reversibly by an addition and a removal of sulfate.     

Molecular Organization of Porphyrin-Metal Complexes

Abstract

Tetraethyltetramethylporphyrin substituted at two facing meso positions by N-methylimidazolyl groupings and its metal complexes were prepared. The absorption spectra of Zn and Mg complexes showed a characteristic splitting of Soret band and red-shifts of Q-bands indicating the exciton interaction of porphyrins in a slipped cofacial arrangement, where each imidazolyl group in one metal porphyrin is coordinated to metals in the other porphyrin skeleton. Typical upfield shifts in the ¹H NMR spectra arising from such the stacking structure elucidated Zn and Mg complexes as a dimer and an oligomeric mixture, respectively. Bis(imidazolyl)substituted tetraethyltetramethyl-porphyrin was also prepared. It suggested the hydrogen bonded oligomer formation through imidazolyl-imidazolyl interactions in a columnar orientation.

Electric conductivities of films prepared from these compounds werecharacterized. In a same line with behaviors in solution, samples capable of π-stacking interaction with adjacent porphyrins via ligand-to-metal coordination or hydrogen bonding exhibited higher conductivities as well as lower activation energies for the thermal conduction. These behaviors are understood as due to the overlap of π-systems of one porphyrin with neighboring porphyrins.     

Photoacoustic Spectra of Complexes of Erbium (III) with Glycine and Alanine

The crystals of the complexes Er(Gly)₃Cl₃. 3 H₂O and Er(Ala)₃Cl₃. 3 H₂O were synthesized and the photoacoustic (PA) spectra in the 300–800 nm region are reported. Their PA and absorption spectra are interpreted. The PA relative intensities represented by intensity branching vectors and the perturbation of ligands on the energy levels of Er³⁺ ion are discussed. The fluorescene properties of Er(Gly)₃Cl₃. 3 H₂O and the relaxation process models were also studied based on the PA and absorption spectra.     

Synthesis and Crystal Structures of Dioxomolybdenum(VI) Complexes with ONS-Donor Ligands

Abstract  

Three dioxomolybdenum complexes namely dioxo(5-chlorosalicylaldehyde thiosemicarbazonato) dimethylsulfoxide molybdenum(VI) (C1), dioxo(5-chlorosalicylaldehyde 2-ethylthiosemicarbazonato) dimethylsulfoxide molybdenum(VI) (C2) and dioxo(5-chlorosalicylaldehyde N-phenylthiosemicarbazonato) dimethylsulfoxide molybdenum(VI) (C3) were prepared. The compounds all crystallize in the triclinic space group P-1 with a = 7.3184(3) ?, b = 7.5035(3) ?, c = 14.9713(6) ?, α = 85.005(2)°, β = 85.616(2)°, γ = 66.987(2)° for C1, a = 8.2339(1) ?, b = 10.1739(1) ?, c = 10.4017(1) ?, α = 78.486(1)°, β = 89.312(1)°, γ = 81.730(1)° for C2, a = 7.0591(1) ?, b = 9.5603(1) ?, c = 14.5762(2) ?, α = 76.280(1)°, β = 81.351(1)°, γ = 81.985(1)° for C3. In general, the overall geometry of these complexes can be regarded as a distorted octahedron with the tridentate thiosemicarbazonato ligands (L²⁻) bonded to the MoO₂ ²⁺ core, with the imine nitrogen, phenoxyl oxygen, sulfur atom and one of the terminal oxygen atoms of the dioxomolybdenum occupying the equatorial position. The sixth coordination site is occupied by the dimethylsulfoxide (DMSO) solvent molecules. The adjacent molecules of C1 are linked by N–H···N intermolecular hydrogen bonding, forming polymeric chains that run parallel to the bc plane. On the other hand, C2 is a discrete molecule while the molecules of C3 associate via weak N–H···O hydrogen bonding interaction to form a polymeric chain that runs along the a-axis.     

On the Crystal Structure of Rare Earth Complexes with 2-Ethylhexyl Phosphoric Acids

The crystal structure of the complexes of some rare-earths (RE = La, Nd, Pr and Er) with bis- and mono-(2-ethylhexyl)phosphoric acids were studied by using the X-ray powder diffraction. The results show that for all RE investigated, the complexes of the diester crystrallize in orthorombic symmetry and cell parameters have been determined. The complexes of the monoester have been found to be nanocrystalline or amorphous.     

New organic–inorganic hybrid mesoporous tantalum oxophosphate and sulfonated tantalum oxophenylphosphate

Novel mesoporous organic–inorganic hybrid tantalum oxophenylphosphate has been synthesized hydrothermally by self-assembly of anionic surfactant sodium dodecyl sulfate (SDS) as structure directing agent under mild alkaline pH conditions. The mesostructure was stable on calcinations in the presence of air and during calcination at 723 K it transformed into pure mesoporous tantalum oxophosphate. Detailed characterizations including elemental analysis, solid state MAS NMR, UV–vis and FT-IR spectroscopic studies suggested the incorporation of phenyl groups in the mesoporous framework and the XRD, N₂ sorption and TEM data suggested wormhole-like mesopore structure in these novel materials. The mesoporous tantalum oxophenylphosphate can be sulfonated by fuming sulfuric acid and the sulfonated derivative showed excellent proton conductivity at room temperature.     

Mesomorphic Complexes of the Lanthanide Elements

Abstract

Mesomorphic lanthanide(III) complexes of salicylaldimine ligands have been synthesised. The effect upon the mesomorphic behaviour is discussed with variation of the counter-anion, number of alkoxy chains and the nature of the ligand framework. Complexes displaying either smectic or columnar mesophases have been realised.     

Synthesis and Crystal Structures of Two Complexes with Carboxylic Derivatives of Nitrogen-containing Heterocycle Ligands

Abstract  

Two new complexes [Zn(pcn)₂(H₂O)₂] (1) and [Cd(inic)₂(H₂O)₄] (2) (pcn = 2-pyrazinecarboxylate, inic = isonicotinic acid) were synthesized by the hydrothermal reaction and characterized by single crystal X-ray diffraction, elemental analysis, IR spectrum and UV spectrum. In complex 1, the Zn(II) central ion is six-coordinated by two oxygen atoms and two nitrogen atoms from pcn ligands and two oxygen atoms from two coordinated water molecules. In complex 2, the Cd(II) central ion is six-coordinated by two nitrogen atoms from isonicotinate ligands and four oxygen atoms from the coordinated water molecules. Both complexes are mononuclear but hydrogen bonds enrich the structural construction. The visible spectra of the complexes between 200 and 300 nm are assigned to intraligand (IL) π–π* transitions of the pyridyl or pyrazine ligands.     

EDA Complexes in Liquid Crystalline Mixed Phases of Novel Compounds with Lateral Dicyanoethenyl Substituents

We synthesized each four members of the new series All compounds are nematic. The dicyanoethenyl derivatives possess strong elecgtron acceptor properties. This is demonstrated by EDA complex formation in two binary systems in which induced smectic phases are lacking.     

The Charge-Transfer Properties of Rare Earth Complexes

Two new Y Cu complexes and some other rare earth complexes crystals are synthesized. The results of elemental analysis, IR, GTA are corresponding to their formula. The PA spectra of all these complexes and the charge-transfer spectra are studied. The strong conjugate π system makes the charge-transfer spectra of rare earth complexes occur in low energy positions with strong intensity. The charge-transfer effect is also existing in the yttrium(III) complex coordinated by some ligands with the conjugate π system.     

Synthesis and Characterization of Polyphenothiazene Iodine Complexes

Abstract

N-methyl 3,6 dibromophenothiazene has been polymerized by using a nickel complex-assisted Grignard coupling. Vapor phase iodine doping of the organometallic polymerized material led to a conductivity increase of 10^?11 ohm^?1 cm^?1 to 10^?5 ohm cm^?l at room temperature. The complex thus formed exhibited a semiconductor behavior with a thermal activation energy of 0.1 eV and a strong electronic IR absorbance from 4000–400 cm^?1. However, the complexed polymer could be dissolved in liquid I₂ and cast into films with air stable, room temperature conductivities as high as 1 ohm^?l cm^?l. The mechanisms that could give rise to these differences in behavior will be discussed.     

Synthesis and Structural Characterization of Two Tetra-Coordinated Co(II) Complexes with Benzimidazole Derivatives

Crystallography Reports - Two mononuclear tetra-coordinated cobalt(II) complexes with molecular formula [Co(L)2(SCN)2] (L = 1-methylbenzimidazole (mbim), 1; L = 1-methyl-2-aminobenzimidazole...     

Crystal Structure and Photoluminescent Properties of Two Cadmium(II) Complexes with Orotic Acid

Abstract  

Assembly of orotic acid (2,6-dioxo-1,2,3,6-tetrahydropyrimidine-4-carboxylic acid, H₃dtpc) and Cd(OAc)₂·2H₂O gave rise to two complexes [Cd₂(H₂dtpc)₂(H₂O)₆] (I) and [Cd(H₂dtpc)(bpy)(H₂O)]_n (II) (bpy = 2,2′-bipyridine). Complex (I) and (II) have been characterized by X-ray single crystal diffraction, IR, PXRD, TGA and fluorescence spectra. Structural analyses reveal that (I) is a binuclear structure, and complex (II) possesses a one-dimensional infinite zig-zag chain architecture and the chains are further assembled into 2D supramolecular network by strong hydrogen bonding interactions. Crystal data for (I): Monoclinic, space group P2(1)/n, a = 9.3221(19) ?, b = 6.6315(13) ?, c = 15.322(3) ?, β = 102.31(3)°, V = 925.4(3) ?³, Z = 4, R1 = 0.0269, and wR2 = 0.0604; for (II): Monoclinic, space group P2(1)/c, a = 9.9880(2) ?, b = 14.5085(2) ?, c = 11.6957(2) ?, β = 107.976(2)°, V = 1612.10(5) ?³, Z = 4, R1 = 0.0234 and wR2 = 0.0554.     

Birefringence Study in Hydrogen Bonded Complexes

A novel series of linear complementary hydrogen bonded complexes fashioned between p-n-alkylbenzoic acids (nBA) and m-fluorobenzoic acid (FBA) are isolated. The obtained homologous series comprising of seven mesogens are analyzed by polarizing optical microscope (POM), differential scanning calorimetry (DSC) and Fourier Transform Infra-Red (FTIR) spectroscopy. It is interesting to note the correlation between the alkyl chain length and the mesogenic phases. The order of the transitions is examined through Cox parameter, experimentally derived by thermal analysis (DSC). Optical tilt angle studies in smectic C and thermal stability factors for various phases are discussed. Birefringence study by various techniques enabled to measure the refractive index at various phase transitions. These results are compared and conferred with those obtained from conventional refractometer. Further orientational order parameter for various phases has been discussed.