A new organic superconductor,beta-(BDA-TTP)2GaCl4 [BDA-TTP = 2,5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene

The preparation, crystal structure and physical properties of beta-(BDA-TTP)2GaCl4 has been investigated; the salt exhibits superconductivity at 3.1 K (onset) under a hydrostatic pressure of 7.6 kbar.     

First radical cation salts of 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) with copper(II) metal complex anions: β-(BDA-TTP)4Cu2Cl6 and (BDA-TTP)2CuCl4

New radical cation salts based on 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) with copper(II) metal complex anions, β-(BDA-TTP)₄Cu₂Cl₆ and (BDA-TTP)₂CuCl₄, were synthesized and structurally characterized. Single crystals were prepared by electrochemical oxidation of BDA-TTP under galvanostatic conditions. X-ray diffraction study demonstrated that the salts have a layered structure, in which the conducting BDA-TTP layers alternate with the [Cu₂Cl₆]²⁻ or [CuCl₄]²⁻ anions. Both salts show the semiconductor-type temperature dependence of the conductivity. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 48–54, January, 2007.     

New organic superconductors beta-(BDA-TTP)2X [BDA-TTP + 2,5-bis(1,3-dithian-2ylidene)-1,3,4,6-tetrathiapentalene; X(-) = SbF6(-), AsF6(-), and PF6(-)].

The synthesis, electrochemical properties, and molecular structure of a new pi-electron donor, 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP), is described. In contrast to the hitherto-known tetrachalcogenafulvalene pi-donors providing organic superconductors, this donor contains only the bis-fused 1,3-dithiole-2-ylidene unit as a pi-electron system, yet produces a series of ambient-pressure superconductors beta-(BDA-TTP)2X [X = SbF6 (magnetic T(c) = 6.9 K, resistive T(c) = 7.5 K), AsF6 (magnetic T(c) = 5.9 K, resistive T(c) = 5.8 K), and PF6 (magnetic T(c) = 5.9 K)], which are isostructural. The values of the intermolecular overlap integrals calculated on the donor layers of these superconductors suggest a two-dimensional (2D) electronic structure with loose donor packing. Tight-binding band calculations also indicate that these superconductors have the 2D band dispersion relations and closed Fermi surfaces.     

Temperature-concentration dependence of the electrical conductivity of glasses in the Zn(PO3)2-NaF system

Temperature-concentration dependence of the electrical conductivity in glasses of the Zn(PO₃)₂-NaF system was studied and compared with similar dependences for glasses of other systems. The extremal dependences log σ = f([Na⁺]) and {ie937-1} are interpreted from the standpoint of a macroscopically inhomogeneous structure of the glasses under study.     

Anisotropy in the electrical conductivity of rutile TiO(2) in the (110) plane

The bulk electrical conductivity of a TiO(2)(110) single crystal has been measured in all azimuths parallel to the (110) plane using a four-point probe. A distinct anisotropy in the conductivity has been found, with the highest bulk conductivity direction being parallel to the 001 direction.     

Synthesis and electrical conductivity of poly(1,4-phenylenevinylene-co-2-nitro-1,4-phenylenevinylene)

A series of PPV copolymers containing 2-nitro-1,4-phenylenevinylene (NO₂-PV) units were prepared via the water-soluble precursor route. They were obtained in film form and were doped with I₂ and FeCl₃. Doping increased the electrical conductivities to maximum values of about 3×10^?2 and 3×10^?1 s cm^?1, respectively, for the two dopants. Conductivity depended strongly on the composition of the copolymers; it reached a maximum value at ca. 1–2 mol % of NO₂-PV units in the copolymers and then dropped rapidly with further increase in NO₂-PV content. Electronic effects of the substituent and morphological changes induced by copolymerization appear to interplay intricately, resulting in the occurrence of a maximum conducting composition. © 1993 John Wiley & Sons, Inc.     

Effect of included guest molecules on the normal state conductivity and superconductivity of beta''-(ET)(4)[(H(3)O)Ga(C(2)O(4))(3)].G (G = pyridine,nitrobenzene)

Normal state conductivity and superconductivity together with bulk magnetic susceptibility and magnetization measurements have been measured for two molecular charge-transfer salts: beta' '-(ET)4[(H3O)Ga(C2O4)3]G (ET = bis(ethylenedithio)tetrathiafulvalene, G = pyridine for compound I and nitrobenzene for compound II). With the exception of the included guest molecules (G) the crystal structures are almost identical. Both show minima in their electrical transport at 130 K for I and at 160 K for II, but at lower temperatures their behaviors differ markedly. The resistance of I reaches a maximum at 50 K with a further small peak at 2 K and possible superconductivity only below 2 K, whereas that of II increases continuously down to 7.5 K, where an abrupt transition to a superconducting state occurs.     

Studies on thermal reactivity of beta-(1,2-allenyl)butenolides and 2-allyl-3-allenylcyclohex-2-enones

A series of thermal pericyclic reactions of beta-allenylfuranones have been studied. It was observed that beta-allenylfuranones would undergo 1,5-hydrogen shift to afford a new type of trienes upon heating. Due to their high reactivity, these trienes would undergo subsequent pericyclic reactions based on the nature of the substituent group R: When R is an alkyl group, the intermediate 4a or 4b would undergo a further 1,7-hydrogen shift to afford a more stable conjugated triene 3; with R being phenyl or cyclopropyl group, the 1,7-hydrogen shift was inhibited and the 4-type conjugated triene would form a six-membered ring 5 via 6 pi-electrocyclization. Interestingly, introducing another C=C double bond into the triene intermediate (R = CH=CH2, the 18-type intermediate would undergo 8 pi-electrocyclization reaction to form an eight-membered ring. Such a transformation was also observed with 2-allyl-3-allenylcyclohex-2-enones. The deuterium-labeling mechanistic studies show that the alkyl groups at the allenyl moiety of 1 participated in the isomerization process via 1,7-hydrogen shifts between 18 A, 20 A, and 29 A.     

A convenient AC electrical conductivity (EC) apparatus

A convenient AC electrical conductivity apparatus is described. The sample, which is in the form of a pressed disk, is placed between two platinum plates located in a small cylindrical furnace. A 1–10V, 100 Hz potential is applied to the sample and the resulting current, in μA, is recorded on an X-Y recorder as a function of temperature. An EC curve of the dehydration of BaCl₂ - 2H₂O to BaCl₂ - H₂O is presented to illustrate the operation of the apparatus.     

3d过渡金属的2-羰基丙酸(4-吡啶甲酰基)腙配合物的合成, 表征及导电性质研究

本文制备了2-羰基丙酸(4-吡啶甲酸基)腙(H2PPFH)的六种过渡金属配合物和Mn(II)配合物的单晶。通过元素分析, 红外和紫外光谱, 差热和热重分析对各配合物的结构和性质进行了表征。配合物的通式为M(PPFH).n[H2O(II)=Mn, Fe, Co,Ni, Cu, Zn, n=0～2]。并通过X射线单晶衍射仪对Mn(II)配合物的晶体结构进行了测定。分析表明该晶体属单斜晶系。空间群为P21/n, Z=4, a=1.1252, b=0.9828,c=1.3708nm, β=66.03°, R=0.28。通过配合物的导电性能的测试, 发现它们都具有半导电性质。     

Spectroelectrogravimetry of the electrical conductivity activation in poly(o-toluidine) films

Journal of Solid State Electrochemistry - The study of the first stages of the transformation of conducting films from the insulating to the conducting form by oxidation is essential to understand...     

Temperature dependent electrical conductivity of polyaniline/Y2O3 composites

Composites of polyaniline with yttrium oxide (Y₂O₃) nanoparticles have been prepared by chemical polymerizations method by increasing the weight percentage of yttrium oxide. X-Ray diffraction (XRD) and Fourier Transform Infrared Spectra (FTIR) were used to characterize the composites. XRD and FTIR pattern indicate that Polyaniline (PANI) is intercalated into the layers of Y₂O₃ nanoparticles successfully by in situ polymerization and therefore the degree of crystallinity increases due to crystalline of yttrium oxide nanoparticles. The scanning electron micrographs (SEM) also confirm the formation of dual phase of platelet as well as of flaky structure in PANI-Y₂O₃. Temperature dependant DC conductivity showed three dimensional variable ranges hopping (3D VRH) model. Activation energy, density of states and hopping length are calculated and found to be influenced by intercalating PANI into the layers of Y₂O₃ clay.     

Analysis of 2beta-carbomethoxy-3beta-(4-fluorophenyl)-N-(3-iodo-E-allyl)nortropane in rat plasma. I. Method development and validation by capillary electrophoresis

Altropane, 2beta-carbomethoxy-3beta-(4-fluorophenyl)-N-(3-iodo-E-allyl)nor tropane, is an imaging agent that was developed recently for early detection of Parkinson's disease. Its promise as a useful radiopharmaceutical for single-photon emission computed tomography or positron emission tomography imaging of the brain has been well demonstrated, and it is currently undergoing clinical trials. This paper presents methods development and validation of capillary electrophoresis (CE) techniques to analyze Altropane in aqueous environments as well as in rat plasma, using an internal standard, nicotinamide. N-Allylaltropane, 2beta-carbomethoxy-3beta-(4-fluorophenyl)-N-allylnortropane, which is a known degradation product of the Altropane precursor (tributyltinaltropane), was used to verify the method's specificity. A solid-phase extraction method for extraction of Altropane from rat plasma is also described. The results presented in this paper demonstrate the applicability of CE methods to study the pharmacokinetic properties of Altropane in animal models. The results of the pharmacokinetic study will be published later, as Part II.     

Cu2I2(PPh3)3.DMF的合成和晶体结构

Ｃｕ２Ｉ２（ＰＰｈ３）３·ＭＤＦ（Ｐｈ＝Ｃ６Ｈ５,ＤＭＦ＝ＨＣＯＮ（ＣＨ３）２是通过Ｗ２Ｓ４（Ｓ２ＣＮ－（ＣＨ２ＣＨ２ＯＨ）２）２,ＰＰｈ３和ＣｕＩ在ＣＨ２Ｃｌ２和ＤＭＦ为溶剂,在室温条件下合成的晶体产物。其窨群为Ｐ２１／Ｃ,晶胞参数：Ｃ５７Ｈ５２Ｃｕ２Ｉ２ＮＯＰ３,α＝１５．８６３（５）,ｂ＝１９．６１９（７）,ｃ＝１８．２３２（４）,Ａ,β＝１０９．５３（２）°,Ｖ＝５３４８（３）Ａ＾３,Ｚ＝     

Synthesis and electrical conductivity of poly(arylene vinylene). I. Poly(2,5-dimethoxyphenylene vinylene) and poly(2,5-dimethylphenylene vinylene)

The highly conjugated aromatic polymers, poly(2,5-dimethoxyphenylene vinylene) and poly(2,5-dimethylphenylene vinylene), were obtained from their water soluble, sulfonium salt precursor polymers. Films of these polymers were reacted with either AsF₅ or I₂ vapor. Poly(2,5-dimethoxyphenylene vinylene) showed increases in electrical conductivity of up to 14 to 15 orders of magnitude for these two dopants, while an 8 to 9 order of magnitude increase was observed for poly(2,5-dimethylphenylene vinylene) with the same dopants. The synthesis of the precursor polymers, the properties and elimination reactions of films of the precursors, the doping reactions, and the conductivities of the resulting phenylene vinylene films are discussed.     

Formation and Crystal Structure of the Salt (IC(PPh3)2)2I[I3]·(I2)2 with a new Polyiodide Chain

The reaction of the carbodiphosphorane Ph₃P=C=PPh₃ ( 1 ) with MeI in the presence of iodine gives the oxidation product (IC(PPh₃)₂)₂I[I₃]·(I₂)₂ ( 2 ). In the solid state dimeric units linked by indefinite ···I^?···I₂···I₃^?···I₂···I^?··· chains are found. An additional I···I contact between the cation and the I₂ molecule is formed, amounting to 359.23(5) pm. 2 crystallizes in the monoclinic space group P2/c, with the unit cell dimensions a = 2053.9(1), b = 1011.4(1), c = 1889.8(1) pm; β = 105.21(1)° and Z = 4.     

N-alkylation and N-acylation of polyaniline and its effect on solubility and electrical conductivity

Various alkylating and acylating agents, with different electrophilicity, were allowed to react with polyaniline “emeraldine base” (Pan-EB) or its anion. Replacing the N-hydrogens of polyaniline by various acyl or benzyl groups strongly affected the solubility and the electrical conductivity of the polymer. Neutral Pan-EB was reacted with benzoyl chloride, p-t-butylbenzoyl chloride or pivaloyl chloride in N,N′-dimethylpropylene urea (DMPU) solutions. While the benzoyl and pivaloyl derivatives showed very poor solubility in common organic solvents, the p-t-butylbenzoyl derivative was readily soluble in THF, chloroform, DMSO, etc. As expected, these acyl derivatives showed diminished electrical conductivity relative to that of the parent Pan-EB. Benzyl chlorides did not react with neutral Pan-EB. Attempts to prepare solutions of the nitrogen anion of Pan-EB by reaction with sodium hydride in DMSO or DMPU led invariably to crosslinked insoluble material. This was ascribed to Michael addition of the formed nitrogen anions to the quinonimine moieties. However forming the nitrogen anion in presence of p-t-butylbenzyl chloride trapped it to form N-benzylated Pan-EB. This was a soluble high molecular weight, electrically conductive (4.3 × 10⁻¹ S cm⁻¹ as the hydrochloride) N-alkyl Pan-EB. Reacting Pan-EB with excess of both sodium hydride and benzyl chlorides led to film-forming per-benzylated Pan-leucoemeraldine reduced form. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1673–1679, 1997     

Synthesis of 2(3H)-benzoxazolinone derivatives as potential beta-3-adrenergic receptor ligands

Beta-3-subtype-adrenoceptors mediate lipolysis and in the search for potential beta-3-adrenergic receptor agonists for the treatment of obesity, we designed new arylethanolamines, structures B₁ and B₂, derived from 2(3H)-benzoxazolinone. To obtain these target compounds as starting materials, various N-benzyl-[2(3H)-benzoxazolinon-6-yl]ethylamines were used.     

Single crystalline commensurate metallic assemblages of pi-slabs and CdI2-type layers: synthesis and properties of beta-(EDT-TTF-I2)2[Pb5/6 square 1/6I2](3) and beta-(EDT-TTF-I2)2[Pb2/3+xAg1/3-2x square xI2]3, x = 0.05

The ability of I...I van der Waals interactions to direct the self-assembly of slabs of the radical cation of ethylenedithio-1,2-diiodo-tetrathiafulvalene, EDT-TTF-I(2), and polymeric lead iodide covalent anionic layers is demonstrated by the synthesis of single crystals of beta-(EDT-TTF-I(2))(2)(.+)[(Pb(5/6) square (1/6)I(2))(1/3-)](3), triclinic, P-1, a = 7.7818(8), b = 7.9760(8), c = 19.9668(2) A, alpha = 82.409(12), beta = 85.964(12), gamma = 61.621(11) degrees, V = 1080.76(19) A(3), R1, wR2 = 0.0459, 0.0947; and beta-(EDT-TTF-I(2))(2)(.+)[(Pb(2/3+x)Ag(1/3-2x)square(x)I(2))(1/3-)](3), x approximately 0.05, triclinic, P-1, a = 7.7744(8), b = 7.9193(8), c = 19.834(2) A, alpha = 87.189(12), beta = 83.534(12), gamma = 61.602(11) degrees, V = 1067.4(2) A(3), R1, wR2 = 0.0508, 0.0997. The state-of-the-art, combined microprobe and structural analysis of the metal site vacancies and occupancies patterns reveal a commensurate organic-inorganic interface and point out the importance of halogen.halogen van der Waals interactions to future studies aiming at directing interface topologies. The electronic structure, room-temperature metallic character and metal-insulator transition at ca. 70 K of the two-dimensional organic slabs are retained upon alloying of the inorganic sublattice with monocations. The room-temperature conductivity of the metallic lead-silver alloy is 2 orders of magnitude larger than that of beta-(EDT-TTF-I(2))(2)(.+)[(Pb(5/6) square (1/6)I(2))(1/3-)](3). This calls for the study of materials with diverse alloying patterns with metal cations of different nature and charge.