Organic conductor θ-(BEDT-TTF)Cd<Subscript>1.38</Subscript>I<Subscript>3</Subscript> with layered perovskite-like structure

The organic conductor θ-(BEDT-TTF)Cd_1.38I₃ (1) (BEDT-TTF is bis(ethylenedithio)- tetrathiafulvalene) with layered perovskite-like structure was synthesized. In the crystal structure of 1, θ-type organic conducting layers, which are built up from BEDT-TTF stacks, alternate with inorganic insulating layers. The latter are composed of CdI₆ octahedra and CdI4 tetrahedra linked together to form a two-dimensional anionic network. Measurements of the temperature dependence of the electrical resistance demonstrated that compound 1 is a semiconductor.     

A new radical cation salt bis(ethylenedithio)tetrathiafulvalene with [Pt(NO2)4]2− anion: Synthesis, structure, and conductivity

A radical cation salt based on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) containing the [Pt(NO₂)₄]^2? anion was synthesized for the first time. The crystal and molecular structure of this salt, (BEDT-TTF)₂Pt(NO₂)₄, was established by X-ray diffraction analysis. The crystal structure consists of radical cation BEDT-TTF layers between which planar-square anions [Pt(NO₂)₄]^2? are located. The layers are formed by BEDT-TTF stacks built of dimers. The interplanar distances within the dimers and between them are 3.41 and 3.96 Å, respectively. The distribution of the bond lengths and bond angles in BEDT-TTF corresponds to the charge of the cation +1. The room-temperature conductivity of (BEDT-TTF)₂Pt(NO₂)₄ is 3·10^?3 Ω^?1 cm^?1, and the temperature dependence of the conductivity exhibits the semiconducting character.     

Tetrathiafulvalene-based organic conductors with Pb-containing anions

Hybrid compounds containing organic layers composed of tetrathiafulvalenes (BEDT-TTF, BETS, BEDO-TTF) and inorganic layers consisting of anions based on lead bromide were synthesized. The crystal structure of (BEDT-TTF)₆Pb₃Br₁₀(PhBr) was determined. The temperature dependences of electrical conductivity for the synthesized compounds were measured and the EPR spectra of these compounds were recorded. In the structure of (BEDT-TTF)₆Pb₃Br₁₀(PhBr), the organic conducting layers of BEDT-TTF molecules alternate with non-conducting layers composed of infinite chains of bromoplumbate anions [Pb₃Br₉]^3–, solvent molecules, and Br^– anions. The newly synthesized BEDT-TTF bromoplumbates have similar linewidths of EPR signals, which indicate that their conducting layers have similar structures. The BEDT-TTF bromoplumbates are semiconductors, while temperature-dependent electrical resistivity measurements show the metallic behavior for BEDO-TTF and BETS bromoplumbates.     

New low-dimensional molecular conductors based on bis(ethylenedithio)tetrathiafulvalene radical cation salts with octahedral metal complex anion [Re<Superscript>IV</Superscript>Cl<Subscript>6</Subscript>]<Superscript>2–</Superscript>

Three new radical cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with the magnetic metal complex anion [Re^IVCl₆]^2–, viz., β-(BEDT-TTF)₂[ReCl₆] (1), α´-(BEDT TTF)₄[ReCl₆]?(DCE)₂ (2), and δ-(BEDT-TTF)₄[ReCl₆]_1.33?(CB)_0.67 (3) (DCE is dichloroethane, CB is chlorobenzene), were synthesized for the first time. The X-ray diffraction analyses of the obtained crystals at room and low temperatures showed that all of them had the sandwich structure characteristic of alternating anionic and cationic layers, which is characteristic of conducting radical cation salts. The structural phase transition accompanied by unit cell tripling and decreasing the symmetry from monoclinic to triclinic in the low-temperature phase occurs in the crystals of salt 2. The transition is related to modulated displacements of both [Re^IVCl₆]^2– anions and BEDT-TTF radical cations. A specific feature of the crystals of salt 3 is a strong positional disorder in the anionic layer, which is expressed as a random distribution of [Re^IVCl₆]^2– anions and CB solvent molecules in a ratio of 2 : 1 along the channels in the ordered cationic framework.     

Ferroelectric liquid crystal dopants with a chiral (R,R)‐2,3‐difluorooctyloxy side‐chain: host dependence of the polarization power

The polarization powers δ_p of four chiral dopants with (R,R)‐2,3‐difluorooctyloxy side‐chains were measured in four liquid crystal hosts with isotropic (I)–nematic (N)–smectic A (SmA)–smectic C (SmC) phase sequences. The four chiral dopants differ in terms of their core structures: 2‐phenylpyridine (MDW950), biphenyl (5), 2‐phenylpyrimidine (6) and 2‐(3‐nitrophenyl)pyrimidine (7). In each case, δ_p varies with the structure of the liquid crystal host, which is consistent with the behaviour of so‐called Type II dopants that normally feature a chiral core structure. The δ_p(host) profile was found to depend on the degree of biaxiality of the dopant core structure, and on the degree of steric coupling between the chiral 2,3‐difluorooctyloxy side‐chain and the core. Conformational analyses at the B3LYP/6‐31G* level suggest that the 2,3‐difluorooctyloxy side‐chain is conformationally more rigid than conventional chiral side‐chains due to the added electrostatic repulsion of the two adjacent fluoro groups combined with the hyperconjugative ‘gauche effect’, and may therefore have a higher degree of biaxiality on the time average. This biaxial character should make the chiral side‐chain more sensitive to variations in quadrupolar ordering imposed by the SmC phase of the liquid crystal host, and may therefore explain the dependence of δ_p on the host structure reported herein.     

Crystal and molecular structure of (BEDT-TTF)4Cd2I6

The new radical-cation salt (BEDT-TTF)₄Cd₂I₆ has been studied by x-ray diffraction (a=19.284(6), b=12.84(1), c=7.869 (2) Å; α=72.77(4), β=94.44(2), γ= 103.97(3)^o, space group P1, Z=1, d_calc=2.32 g/cm³). The radical cation (BEDT-TTF)^1/2+ and the Cd₂I₆ ^2? anions form organic and inorganic layers alternating along the a axis. In the organic layer, (BEDT-TTF)^1/2+ are arranged in stacks and ribbons. The radical-cations in the ribbon are packed “side to side” and are joined to one another through shortened intermolecular contacts S...S 3.346(5)-3.657(4) Å. The Cd₂I₆ ^2? anion is dimeric. The Cd atom has a distorted tetrahedral bond configuration, with bond lengths Cd-I 2.722(l)-2.886(1) Å and valence angles I-Cd-I 93.8(1)-114.1(1)°.     

Effects of metal ions and ligands on transesterification: synthesis,structures, and catalytic activities of a series of cation–anionic complexes with dipyridylamine ligands

A series of cation–anion complexes derived by 2,2′-dipyridylamine (Hdpa) and carboxylate ligands with formulas [Ni(Hdpa)₂(CH₃COO)]Cl(CH₃OH) (1), [Co(Hdpa)₂(CH₃COO)]Cl(CH₃OH) (2), [Ni(Hdpa)₂(CH₃CH₂CH₂COO)]Cl (3), [Co(Hdpa)₂(CH₃CH₂CH₂COO)]Cl (4), [Ni(Hdpa)₂(C₆H₅COO)]Cl (5), and [Co(Hdpa)₂(C₆H₅COO)]Cl (6), were synthesized and characterized by IR, elemental analysis, MS(ESI), TG analysis, UV-Vis, and fluorescence spectra. X-ray single crystal structural analysis showed that the coordination geometries of metal ions in these complexes are similar and they are cation–anion species. The hydrogen-bonding structures are 1-D chains through the N–H···Cl bonds. There are weak stacking interactions between pyridine rings in 1–4, while there are no stacking interactions in 5 and 6. We have investigated the transesterification of phenyl acetate with methanol catalyzed by 1–6 under mild conditions; 1–4 are homogeneous catalysts while 5 and 6 are heterogeneous catalysts due to their poor solubility in methanol. Cobalt complexes exhibit higher catalytic activities than corresponding nickel complexes. Complex 4 is the best catalyst of these six complexes.     

Crystal and molecular structure of the simple cation-radical salt ethylenedithiopropylenedithiotetrathiafulvalene trichloromercurate (EPT)HgCl3

The new cation-radical salt (EPT)HgCl₃ is prepared. Its structure and electrical conductivity are studied. The crystal structure of (EPT)HgCl₃ contains (EPT)⁺ in the chair conformation and trigonal planar HgCl₃ ^– packed into organic and inorganic layers alternating along thea axis. Shortened intermolecular contacts join HgCl₃ ^– into infinite chains along the c axis (Hg...Cl, 3.289 and 3.387 Å), form stacks (S...S, 3.536 and 3.597 Å) and layers (S...S, 3.427–3.498 Å) of EPT⁺ cation-radicals, and create cation-anion interactions between neighboring layers in the crystal (Cl...S, 3.396–3.521 Å, Cl...C, 3.360 Å). The configuration of the bonds around Hg in HgCl₃ ^– is distorted trigonal planar: Hg-Cl, 2.342(3)–2.449(3) Å, Cl-Hg-Cl, 110.7(1)–137.4(1). The Hg atom lies out of the plane of the Cl atoms by 0.015 Å. The conductivity of (EPT)HgCl₃ at 20°C is ₃₀₀ 5·10^–2 (·cm)^–1. The dependence of conductivity on temperature is semiconducting in nature.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2055–2061, September, 1991.     

Structural features and N-H…O and O-H…O hydrogen-bonded supramolecular frameworks in 2-methylanilinium hydrogen DL-malate hydrate, 4-methoxyanilinium and 4-methylanilinium hydrogen DL-malate salts

In the crystal structure of 2-methylanilinium hydrogen DL-malate hydrate (I), an additional water molecule is present in asymmetric unit. In the crystal structures of 4-methoxyanilinium hydrogen DL-malate (II) and 4-methylanilinium hydrogen DL-malate (III), the hydrogen malate anions exhibit configurational disorder with major component occupy S-configuration and minor component occupy R-configuration provided both (II) and (III) are prepared from a racemic mixture of DL-malic acid. In crystal structures of compounds (I)–(III), the hydrogen malate anions and anilinium cations from O-H…O and N-H…O hydrogen bonds which exhibit interesting supramolecular frameworks. In compound (I), the N-H…O and O-H…O hydrogen-bonded anionic-cationic framework form two-dimensional hydrophilic and hydrophobic layers in which the lattice water molecules are embedded in hydrophilic layers. However, in crystal structures of (II) and (III), the hydrogen DL-malate anions form two-dimensional anionic substructure through O-H…O hydrogen bond, in which the anilinium cations are anchored through N-H…O hydrogen bonds.

     

Syntheses of [(η 6- p -cymene)Ru(EPh3)2Cl]+ complexes and molecular structure of chloro(η 6- p -cymene)-bis(triphenylphosphine)ruthenium(II) tetrafluoroborate (E = P,As and Sb)

The reaction of [(η⁶-p-cymene)RuCl₂]₂ with excess EPh₃ (E = P, As, Sb) in methanol in the presence of ammonium tetrafluoroborate leads to the formation of complexes of the type [(η⁶-p-cymene)Ru(EPh₃)₂Cl]BF_4, E = P (1), As (2), Sb (3), which arise through cleavage of the chloride bridges. These complexes were characterized by spectral and analytical data. The crystal structure of 1 was solved by single-crystal X-ray crystallography in order to establish the exact structure in the solid state. The complex crystallizes in monoclinic space group P2₁/n (#14) with a = 12.42500(10), b = 30.1925(3), c = 11.06530(10)?Å, β = 103.1470(10)°.     

Hydrogen-bonding network in the organic salts of 4-nitrobenzoic acid

The crystal structures of six novel salts of 4-nitrobenzoic acid — namely, 2-hydroxyethylammonium 4-nitrobenzoate (I), 2-hydroxypropylammonium 4-nitrobenzoate (II), 1-(hydroxymethyl)propylammonium 4-nitrobenzoate (III), 3-hydroxypropylammonium 4-nitrobenzoate (IV), bis-(2-hydroxyethylammonium) 4-nitrobenzoate (V), morpholinium 4-nitrobenzoate (VI) — containing the same anion but different cations have been studied. The ionic forms of I-VI serve as building blocks of the supramolecular architecture, and in crystals they are held together via ionic N-H···O and O-H···O hydrogen bonds. In the crystal packing the building blocks of I-III are self-assembled via N-H...O, O-H···O and C-H...O hydrogen bonds to form the chains which are further consolidated into two-dimensional layers by the same type of interactions. In IV-VI the chain-like structures have been generated by building blocks.     

Structure of (BEDT-TTF)-Based Organic Metals with Photochromic Nitroprusside Anion (BEDT-TTF)4M[FeNO(CN)5]2, where M = Na+, K+, NH+4, Tl+, Rb+, and Cs+

The crystal and molecular structures of a family of three-component radical cation salts bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF), (BEDT-TTF)₄M[NP]₂, where M = Na⁺, K⁺, NH⁺ ₄, Tl⁺, Rb⁺, and Cs⁺and NP is the nitroprusside anion [FeNO(CN)₅]^2–, are studied by X-ray structure analysis. These salts are isostructural and behave as stable metals down to helium temperatures. Their structures are characterized by radical cation layers of the "-type alternating with layers of complex anions [M⁺(NP^2–)₂]^3–. The conducting radical cation system and photochromic nitroprusside anion in the crystals were shown to affect each other. On the one hand, this changes the geometric parameters of the nitroprusside anion as compared to those of the Na₂[NP] · 2H₂O crystals in the ground state and, on the other hand, makes the geometries of the two crystallographically independent BEDT-TTF molecules with a different number of shortened contacts with the anion different. Based on the data of crystallochemical analysis of the (BEDT-TTF)₄M[FeNO(CN)₅]₂structures, we suggest their possible routes of chemical modification with the purpose of changing their physical properties.     

C—H⋯π, π–π and C—H⋯Cl interactions in chloro‐substituted Schiff bases and 4‐chloro‐N‐[4‐(di­methyl­amino)­benzyl­idene]­aniline

Molecular packing analyses were carried out on 15 crystal data sets of chloro‐substituted Schiff bases, including that of the title compound, C₁₅H₁₅ClN₂. C—H⋯π and π–π interactions play a major role in the molecular self‐assembly in the crystal. The former interactions favor mol­ecules assembling into a screw, with a non‐centrosymmetric crystal structure. When the molecular dipole is small, π–π interactions favor a parallel, but not usually antiparallel, mode of packing. Weak C—H⋯X hydrogen bonds (X = Cl or Br) and X⋯X interactions seem to be a secondary driving force in packing. The title mol­ecule takes the trans form and the two benzene rings are twisted around the central linkage in opposite directions. In the crystal structure, mol­ecules interact through C—H⋯π and π–π interactions, forming a `dimer' and further forming double chains along [001]. The double chains are extended along [10] through C—H⋯Cl hydrogen bonds, forming double layers in (010). In the third direction, there are only ordinary, weaker, van der Waals interactions, which explains the crystal habit (i.e. thin plate).     

Neue Synthesen von Me2SbX (X = Cl,I) und Kristallstrukturen von Me2SbI und [(Me3Si)2CH]2SbCl

Novel Syntheses of Me₂SbX (X = Cl, I) and Crystal Structures of Me₂SbI and [(Me₃Si)₂CH]₂SbCl The crystal structures of Me₂SbI (Me = CH₃) and [(Me₃Si)₂CH]₂SbCl have been determined by X‐ray methods. Both molecules are pyramidal. The Me₂SbI molecules are associated to chains through short intermolecular Sb…I distances (366,7(1) pm) with linear I–Sb…I units (171,87(4)°) and bent Sb–I…Sb bridges (116,83(3)°).     

Unexpected complexation of allylpseudothiohydantoin hydrochlorides towards CuX (X = Cl,NO3, ClO4, BF4, 1/2SiF6). The first known examples of joint CuI(Cl,ClO4) and CuI(Cl,BF4) π-complexes

By means of alternating current-electrochemical synthesis starting from a mixture of 2-imino-3-(prop-2-en-1-yl)-1,3-thiazolidin-4-one (3-allylpseudothiohydantoin, napt) and 2-allylamino-1,3-thiazol-4(5H)-one (allylaminopseudothiohydantoin, aapt) hydrochlorides and corresponding copper(II) salts five new π-complexes, [Cu(napt)Cl] (1), [Cu₂(aapt)₂Cl]NO₃ (2), [Cu₂(aapt)₂Cl]BF₄ (3), [Cu₂(aapt)₂Cl]ClO₄ (4) and [Cu₂(aapt)₂Cl]₂SiF₆·2H₂O (5), were obtained and studied by X-ray single crystal diffraction and IR-spectroscopy. Napt and aapt molecules are selectively coordinated to Cu⁺ depending on the anion type. In crystals of 1 and 5, the organic ligands are attached to the metal in a chelating N,(C=C)-bidentate mode. The aapt molecule in 2-4 acts as a tridentate chelating ligand, being coordinated to the copper(I) ion through the heterocyclic N atom, carbonyl O atom, and C=C bond of allyl group, forming an original cationic [Cu₂(aapt)₂Cl]⁺ fragment with both a bridging Cl^– ion and O atom of the C=O group. In the presence of the doubly charged SiF₆^2– anion, Cu(I) in 5 prefers to be bonded with two bridging Cl^– ions, rather than the C=O group, causing [Cu₂(aapt)₂Cl]⁺ units to associate into the infinite cationic chains. Crystals of 3 and 4 are the first known examples of the simultaneous BF₄^–/Cl^– or ClO₄^–/Cl^– participation in copper(I) π-complex formation.     

Element-Element-Bindungen. VI. Kristallines 2-Chlor-1,3,2-benzoxathiastibol – ein mehrfach verknüpftes Koordinationspolymeres

Element-Element-Bonds. VI. Crystalline 2-Chloro-1,3,2-benzoxathiastibole – a Multiply Linked Coordination Polymer Yellow 2-chloro-1,3,2-benzoxathiastibole 4a first prepared by Anchisi and coworkers [3] from o-hydroxythiophenol and antimony trichloride, crystallizes in the monoclinic space group P2₁/n {a = 1109.9(3); b = 610.5(2); c = 1201.5(2) pm; β = 100.35(2)° at ?120 ± 3°C; Z = 4}. An X-ray structure determination (R = 0.029) shows the molecules to form coordination polymeric layers via Sb…?Cl, Sb…?O and Sb…?η²-arene interactions in the solid. Characteristic structural features are Sb? Cl…?Sb? Cl helices (Sb? Cl…?Sb 119°; Cl? Sb…?Cl 95°) and centrosymmetric, four membered Sb₂O₂-rings (O? Sb…?O 64°; Sb? O…?Sb 116°). The ligands set up a strongly distorted octahedron around the antimony atom: Sb? S 242; Sb? Cl 243; Sb…?Cl 328; Sb? O 201; Sb…?O 287; Sb…?C 338 and 341 pm; S? Sb? O 85°; S? Sb? Cl 94°; O? Sb? Cl 92°.     

Field Effects in Nematic Liquid Crystals in Terms of Catastrophe Theory

Abstract

The field effects in nematic liquid crystal layers are reanalysed using catastrophe theory. The layer with pretilted director orientation and obliquely applied magnetic field, the hybrid aligned nematic cell and twisted nematic structures are considered. The stable solutions are identified and transitions between them are specified. The results are in essential agreement with previous work. Some details concerning the behaviour near the threshold are revealed.     

Syntheses and structures of Cd(II) and Co(II) compounds of 4-[(3-pyridyl)methylamino]benzoate anion

Three coordination polymers containing Cd(II) and Co(II), connected via 4-[(3-pyridyl)methylamino]benzoate (L^?), have been synthesized in hydrothermal conditions. In [Cd(L)Cl] _n (1), adjacent Cd(II) cations are linked by carboxylates to give a dinuclear cluster. Pairs of L^? bridge the dinuclear cluster to form double helical chains, and these chains are further linked by Cl^? to produce a 4-connected net with (4²?·?6³?·?8) topology. [CdL₂] _n (2) contains 1-D ladder-like chains. The packing structure displays a 3-D supramolecular structure, with π?···?π interactions stabilizing the framework. [CoL₂] _n (3) has a 2-D extended supramolecular structure via π?···?π interactions of 1-D coordination polymers of 3. The crystal structures of 1–3 have been determined by single-crystal X-ray diffraction. Luminescent properties for 1 and 2 are discussed.     

Synthesis, crystal structure, and conducting properties of a new molecular conductor (DBTTF)11(TeCl6)4

The structure and conducting properties of a new radical cation salt of dibenzotetrathiafulvalene (DBTTF),viz., (DBTTF)₁₁(TeCl₆)₄ (1), were studied. According to the X-ray diffraction data, the crystal of1 contains six crystallographically independent DBTTF radical cations alternating with stacks of the (TeCl₆)²⁻ anions. At room temperature, the conductivity of the crystals is 15 S cm⁻¹ and it changes exponentially as the temperature decreases. It was found that an increase in the size of the anion in compounds of type1 results in the appearance of interactions between the stacks and in an enhancement of the two-dimensional character of the conductivity. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 370–372, February, 2000.     

Keggin Arsenomolybdate Based Hybrid Compound with Complementary Inorganic Double Helical Chains

A new Keggin arsenomolybdate based inorganic–organic hybrid compound containing complementary inorganic double helical chains, [Ag₂(pyttz)₃(H₂O)][HAsMo₁₂O₄₀]·H₂O (1), was successfully synthesized and characterized. Single crystal X-ray analysis reveals that compound 1 exhibits 3D supramolecular framework with (4³)(4⁴·6²)(4⁷·6¹⁰·8⁴) topology, in which the complementary double helical chains constructed by the left- and right-handed helical chains are found. In the crystal engineering point of view, the rich coordination atoms and conjugated heterocyclic rigid plane of pyttz organic ligand and the multiple twisted V-shaped coordination modes of Keggin POMs facilitate the formation of the inorganic helical structure. In addition, the title compound exhibits good photocatalytic degradation of methylene blue dye, and is very stable and easily separated from the catalytic system for reuse as well.