Polyfuran/zeolite LTA composites and adsorption properties

Composites of polyfuran (PFu) with LTA type (3A, 4A, 5A) zeolites were prepared via chemical oxidative polymerization of furan (Fu) in the presence of a dispersion of zeolites (powder) in ACN solvent using anhydrous FeCl₃ oxidant at an ambient temperature. The composites were characterized by Fourier transform infrared spectroscopic (FTIR) analysis. FTIR results showed that the composites of 3A zeolite with the smallest pore size did not indicate absorption for benzoyl chloride due to surface structural of OH groups. Thermogravimetric analysis revealed the stability order as: 3A > PFu/3A > PFu, 4A > PFu/4A > PFu, 5A > PFu/5A > PFu. Scanning electron microscopic analysis and X-ray diffraction analysis indicated the formation of polyfuran on zeolite structures. Conductivity values of samples are in the range of semi conductors.     

High‐performance Flexible Complementary Electrochromic Device Based on Plasma Modified WO3 Nano Hybrids and V2O5 Nanofilm with Low Operation Voltages

Tungsten trioxide‐poly(3,4‐ethylenedioxythiophene) (WO₃‐PEDOT) and tungsten trioxide‐polyfuran (WO₃‐PFu) were prepared by rf rotating plasma polymerization. Electrochromic hybrid thin films were fabricated onto flexible polyethylene terephthalate (PET)/ indium tin oxide (ITO) film using electron beam evaporation method. In order to deeply characterize all films, scanning electron microscopy‐energy dispersive X‐ray spectroscopy (SEM‐EDS) and electrochemical impedance spectroscopy (EIS) techniques were used. The counter electrode effect on plasma modified WO₃ nano hybrids‐based electrochromic devices (ECDs) was evaluated. By incorporating flexible vanadium pentoxide (V₂O₅) film as counter electrode, complementary ECDs were constructed through combining the hybrid flexible films (WO₃‐PEDOT, WO₃‐PFu) as working electrodes, which exhibit highly efficient electrochromic performance with low voltage operation. Especially, WO₃‐PEDOT/V₂O₅‐based ECD owns a high optical modulation of 61.5 % at 750 nm driven by −1.0 V (coloration) and +1 V (bleaching) with fast response times (coloration time: 13.58 s, bleaching time: 8.07 s) and a high coloration efficiency of 527 cm² C⁻¹. This study can supply useful and efficient avenue for designing flexible complementary electrochromic device for energy‐saving flexible electronics.     

烷基咪唑离子液体对脂肪酶催化酯水解反应活性的影响

考察了1-烷基-3-甲基咪唑类离子液体对柱状假丝酵母脂肪酶(CRL)催化橄榄油水解反应活性的影响,利用电导法确定了磷酸盐缓冲液中Br^-,Cl^-,[BF₄]^-系列咪唑离子液体的临界胶束浓度(CMC)和[PF₆]^-系列咪唑离子液体的溶解度.结果显示,离子液体的阴、阳离子对酶活性的影响规律与离子液体的Kosmotropicity性质无明显关联,但与离子液体在体系中的含量密切相关,在最适离子液体含量时,酶活性达到最高;阳离子[C_nMIM]⁺中的n越大,可促进酶活性的离子液体适宜含量越低;Br^-,[BF₄]^-系列离子液体的浓度超过CMC时则抑制酶活;阴离子对酶活性的最大促进作用顺序为Br^->Cl^->[BF₄]^->[PF₆]^-.离子液体对酶活性的影响随体系pH和温度的不同而改变,在最适离子液体浓度时的最适pH均为7.000.在pH 7.000,30 ^oC以及[C₈MIM]Br离子液体浓度为47.6 mmol/L的最佳条件下,最高相对酶活力和比活力分别达到1734%和54.4 U/mg protein.     

Preparation and characterization of polyfuran/poly(2‐fluoroaniline) conducting composites

This article deals with the chemical synthesis and characterization of poly(2‐fluoroaniline) (P2FAn) and polyfuran (PFu) homopolymers and PFu/P2FAn and P2FAn/PFu composites. P2FAn and PFu homopolymers were synthesized using ammonium persulfate and antimony (III) chloride as catalyst, respectively. These homopolymers and composites were studied in the doped state using Fourier transform infrared spectroscopy and ultraviolet–visible absorption spectroscopy, thermogravimetric analysis, scanning electron microscopy, four‐probe conductivity technique, and Gouy Scale measurements. PFu/P2FAn and P2FAn/PFu composites were found to possess different thermal, conductivity, electronic, and morphological properties from each other when synthesis order of guest and host polymers was varied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3359–3367, 2004     

ChemInform Abstract: Superhalogens as Building Blocks of Halogen-Free Electrolytes in Lithium-Ion Batteries.

In the search for halogen-free electrolytes, the electronic structure of current electrolytes is studied via DFT-based first-principles calculations of the ground state geometries and total energies of anionic BF₄^-, PF₆^-, AsF₆^-, FePO₄^-, ClO₄^-, N(SO₂F)₂^-, and N(SO₂F₃)₂^-.     

Spectral Properties of Ruthenium(II) Mixed-Ligands Complexes with 2,2'-Bipyridyl and Phosphines

Spectral-kinetic luminescence characteristics of the complexes cis-[Ru(bpy)(dppe)X2], cis- [Ru(bpy)2(PPh₃)X](BF₄) and cis-[Ru(bpy)₂X₂] [bpy = 2,2'-bipyridyl, dppe = 1,2-bis(diphenylphosphino)ethane, PPh₃ is triphenylphosphine, X = NO₂ ^- and CN^-] in the ethanol-methanol 4:1 mixtures and adsorbed on the oxide SiO₂ or porous polyacrylonitrile polymer surface were studied. Luminescence and luminescence exitation spectra were registered at 77 and 293 K in 230-750 nm range and the luminescence decay time was measured. Introduction of phosphine ligands to the ruthenium(II) bipyridyl complexes inner sphere leads to rise in singlet and triplet state energy at the charge transfer from Ru(II) to 2,2'-bipyridyl in the series [Ru(bpy)₂X₂] < Ru(bpy)₂(PPh₃)X](BF₄) < [Ru(bpy)(dppe)X₂]. The complex adsorption on SiO₂ or polyacrylonitrile surface affects noticeably the luminescence spectro-kinetic characteristics.     

Synthesis of alkene- and alkyne-pentamethylcyclopentadienyl dicarbonyliron complexes via the aquo derivative [Fe(η-C5Me5)(CO)2(OH2)]+BF4-; crystal structure of the ruthenium analogue

[Fe(η-C₅Me₅)(CO)₂(OH₂)]⁺ BF₄^- (2a) reacts with alkenes and alkynes to give the new complexes [Fe(η-C₅Me₅)(CO)₂(alkene)]⁺ BF₄^- and [Fe(η-C₅Me₅)(CO)₂(alkyne)]⁺ BF₄^-. The crystal structure of the ruthenium analogue [Ru(η-C₅Me₅)(CO)₂(OH₂)]⁺ CF₃SO₃^- (2b) is described.     

Ring transformation of cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium ion to the corresponding pyrrole derivatives via troponeimine intermediates: photo-induced autorecycling oxidizing reactions of some amines

Ring transformation of 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]furan- 8(7H),10(9H)-dionylium tetrafluoroborate 4⁺·BF₄⁻ to 7,9-dimethylcyclohepta[b]pyrimido[5,4-d]pyrrrole-8(7H),10(9H)-dionylium tetrafluoroborate 6a-d⁺·BF₄⁻ consists of the reaction of 4⁺·BF₄⁻ with amines and subsequent exchange of the counter-ion using aq. HBF₄. Reactions of 4⁺·BF₄⁻ with aniline and 4-substituted anilines afforded the corresponding pyrrole derivatives 6a-c⁺·BF₄⁻ directly in good yields. On the other hand, reaction of 4⁺·BF₄⁻ with benzylamine gave the troponeimine intermediate 9, which was not converted to 6d⁺·BF₄⁻ and reverted to 4⁺·BF₄⁻ by adding HBF₄; however, it was converted to 6d⁺·BF₄⁻ upon treatment with (COCl)₂ or SOCl₂, followed by exchange of the counter-ion. In a search for the characteristics of 9, inspection and comparison of the X-ray crystal analyses, NMR and UV-vis spectra, and CV measurement of 9 and N,N-disubstituted troponeimine derivatives 12 were carried out to suggest the remarkable structure of 12 having ionic C-O bonding between the imine-carbon atom and the oxygen atom of the barbituric acid moiety in the solid state. Thus, characteristics of 9 were ascribed to the sterically hindered and favorable conformation of N-protonated troponeimine intermediates. Furthermore, novel photo-induced oxidation reactions of a series of 4⁺·BF₄⁻, 5⁺·BF₄⁻, and 6a,e⁺·BF₄⁻ towards some amines under aerobic conditions were carried out to give the corresponding imines in 455-8362% yields [based on compounds 4⁺, 5⁺, and 6a,e⁺], suggesting the oxidation reaction occurs in an autorecycling process. Mechanistic aspects of the amine-oxidation reaction are also postulated.     

离子液体[BMIM]Br与[BMIM][BF4]配比浓度对Br-离子电荷转移的调节

利用X射线吸收精细结构光谱(XAFS)及紫外吸收光谱两种方法, 分析了离子液体1-丁基-3-甲基咪唑溴盐([BMIM]Br)中逐渐掺入1-丁基-3-甲基咪唑四氟硼酸盐([BMIM][BF₄])时, Br^-阴离子与咪唑阳离子之间氢键作用及电荷偏移量的改变. 随着[BMIM][BF₄]加入量增多, Br 元素XAFS近边(XANES)显示吸收峰降低, 吸收边位置向低能端位移0.9 eV; 扩展边(EXAFS)算出径向结构显示Br 与近邻原子间平均配位数降低、平均键长增长; 紫外光谱也有明显蓝移减色效应. 这些结果都表明Br₄^-的掺入改变了Br^-与阳离子间的电荷偏移量, 负电荷更多地转移到Br^-上, 量化计算的数据同样支持该结论.     

Synthesis and properties of novel 5-(cyclohepta-2′,4′,6′-trienylidene)pyrimidine-2(1H),4(3H),6(5H)-triones: methodology for synthesizing cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborates

Novel condensation reaction of tropone with N-substituted and N,N′-disubstitued barbituric acids in Ac₂O afforded 5-(cyclohepta-2′,4′,6′-trienylidene)pyrimidine-2(1H),4(3H),6(5H)-trione derivatives (8a-f) in moderate to good yields. The ¹³C NMR spectral study of 8a-f revealed that the contribution of zwitterionic resonance structures is less important as compared with that of 8,8-dicyanoheptafulvene. The rotational barriers (ΔG^‡) around the exocyclic double bond of mono-substituted derivatives 8a-c were obtained to be 14.51-15.03 kcal mol⁻¹ by the variable temperature ¹H NMR measurements. The electrochemical properties of 8a-f were also studied by CV measurement. Upon treatment with DDQ, 8a-c underwent oxidative cyclization to give two products, 7 and 9-substituted cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborates (11a-c·BF₄⁻ and 12a-c·BF₄⁻) in various ratios, while that of disubstituted derivatives 8d-f afforded 7,9-disubstituted cyclohepta[b]pyrimido[5,4-d]furan-8(7H),10(9H)-dionylium tetrafluoroborate (11d-f·BF₄⁻) in good yields. Similarly, preparation of known 5-(1′-oxocycloheptatrien-2′-yl)-pyrimidine-2(1H),4(3H),6(5H)-trione derivatives (14a-d) and novel derivatives 14e,f was carried out. Treatment of 14a-c with aq. HBF₄/Ac₂O afforded two kinds of novel products 11a-c·BF₄⁻ and 12a,c·BF₄⁻ in various ratios, respectively, while that of 14d-f afforded 11d-f. The product ratios of 11a-c·BF₄⁻ and 12a-c·BF₄⁻ observed in two kinds of cyclization reactions were rationalized on the basis of MO calculations of model compounds 20a and 21a. The spectroscopic and electrochemical properties of 11a-f·BF₄⁻ and 12a-c·BF₄⁻ were studied, and structural characterization of 11c·BF₄⁻ based on the X-ray crystal analysis and MO calculation was also performed.     

聚阴离子掺杂LiMnO_(2-y)X_y(X=BF_4~-,SiO_3~(2-),MoO_4~(2-),PO_4~(3-),BO_3~(3-))材料的合成及其电化学性能

采用水热法合成了聚阴离子掺杂LiMnO2-yXy(X=BF4-,SiO32-,MoO42-,PO43-,BO33-,y=0.01、0.03、0.05)锂离子电池正极材料。通过X射线粉末衍射(XRD)、X光电子能谱(XPS)、扫描电镜(SEM)和恒电流充放实验,研究了不同掺杂离子和掺杂量对产物结构和电化学性能的影响。结果表明,少量聚阴离子的掺杂未改变正交LiMnO2的晶体类型,但增大了材料晶胞体积,改善了材料的电化学循环性能。电化学交流阻抗(EIS)测试结果表明,聚阴离子掺杂增大了材料电荷转移阻抗,但明显提高了材料中Li+的扩散能力。     

Novel photo-induced oxidative cyclization of 1,3-dimethyl-5-(1-arylmethylidene)pyrimidine-2,4,6(1,3,5H)-triones: synthesis and properties of areno[5,6]pyrano[2,3-d]pyrimidine-2,4(1,3H)-dionylium ions and their photo-induced autorecycling oxidizing reaction toward some amines

Novel photo-induced oxidative cyclization was accomplished to synthesize areno[b]pyrimido[5,4-e]pyran-2,4(1,3H)-dionylium ions 13a-c⁺·ClO₄⁻. Furthermore, 13a-c⁺·BF₄⁻ and their phenyl-substituted derivatives 19a,b⁺·BF₄⁻ were alternatively synthesized by the reaction of salicylaldehyde and its naphthyl derivatives with barbituric acids and subsequent treatment with aq. HBF₄. Structural characteristics of 13a-c⁺ and 19a,b⁺ were clarified on inspection of the UV-vis and NMR spectral data as well as X-ray crystal analyses. The electrochemical properties were studied by the CV measurement. In a search for reactivity, reactions of 13a-c⁺·BF₄⁻ with some nucleophiles, hydride, benzylamine, and H₂O, were also carried out. The photo-induced autorecycling oxidation reactions of 13a-c⁺·BF₄⁻ toward some amines under aerobic conditions were carried out to give the corresponding imines (isolated by converting to the corresponding 2,4-dinitrophenylhydrazones) in 643-3600% yield (recycling number of 13a-c⁺·BF₄⁻: 6.4-36.0).     

On the oxidation states of metal elements in MO3- (M=V,Nb, Ta,Db, Pr,Gd, Pa) anions

Relativistic quantum chemistry investigations are carried out to tackle the puzzling oxidation state problem in a series of MO_3~- trioxide anions of all d- and f-block elements with five valence electrons. We have shown here that while the oxidation states of V, Nb, Ta, Db, Pa are, as usual, all +V with divalent oxygen O(-II) in MO_3~- anions, the lanthanide elements Pr and Gd cannot adopt such high +V oxidation state in similar trioxide anions. Instead, lanthanide element Gd retains its usual +III oxidation state, while Pr retains a +IV oxidation state, thus forcing oxygen into a non-innocent ligand with an uncommon monovalent radical(O~·) of oxidation state -I. A unique Pr·- ·(O)_3 biradical with highly delocalized unpairing electron density on Pr(IV) and three O atoms is found to be responsible for stabilizing the monovalent-oxygen species in PrO_3~- ion, while GdO_3~- ion is in fact an OGd~+(O_2~(2-)) complex with Gd(III). These results show that a na?ve assignment of oxidation state of a chemical element without electronic structure analysis can lead to erroneous conclusions.     

The first stable examples of compounds containing both diazonium and acyl azide,and synthesis of a new pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one heterocyclic system

The first stable compound containing both N₂⁺BF₄^? and CON₃ functional groups – 8-azidocarbonyl-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-7-diazonium tetrafluoroborate was synthesized, and its stability and reactivity discussed. The Curtius rearrangement of 7-azido-3-(tert-butyl)-4-oxo-4,6-dihydropyrazolo[5,1-c][1,2,4]triazine-8-carbonylazide was investigated, and the synthesis of a novel heterocyclic system –pyrazino[2′,3′:3,4]pyrazolo[5,1-c][1,2,4]triazin-4(6H)-one is described.     

Ab initio MO study of selected aluminum and boron chlorides and fluorides: Comparison with 11B NMR spectra of a tetrachloroborate melt

Molecular geometries were fully optimized for AlCl₃, AlCl₄^-, Al₂Cl₆, Al₂Cl₇^-, AlF₃, AlF₄^-, Al₂F₆, Al₂F₇^-, BCl₃, BCl₄^-, B₂Cl₆, B₂Cl₇^-, BF₃, BF₄^-, B₂F₆, and B₂F₇^-, as well as a few mixed halogen species, at the Hartree-Fock (HF) level, using basis sets from STO-3G to 6–311 + G(d). In some cases geometries were also optimized at the MP2 level. Where possible, the computed geometries were compared to known structures from electron or X-ray diffraction. The agreement between these was quite good for the neutral species, and somewhat poorer for the anions. Vibrational frequencies were calculated for all species at the HF level with the largest basis set. The geometries were characterized as minima or transition structures. Various formation reaction enthalpies were calculated; these compare well with known values. More extensive calculations on the BF₃/BF₄^- system indicate the structures and enthalpies are nearly converged with respect to basis set size and level of correlation treatment. The previously unknown species B₂Cl₇^- is predicted to be energetically stable on the basis of the calculations. Some features of the ¹¹B NMR spectra of room temperature melts consisting of mixtures of boron trichloride with 1-methyl-3-ethylimidazolium chloride are presented. These features suggest that these melts may contain small amounts of B₂Cl₇^- as an intermediate in an exchange reaction. © 1996 by John Wiley & Sons, Inc.     

Tris(triphenylphosphinegold)oxonium salts

The oxonium salts (Ph₃PAu)₃O⁺X^- where X^-  BF₄^-, CF₃COO^-, MnO₄^- have been prepared. These salts are formed from coordinatively unsaturated Ph₃PAu⁺ cations in alkaline or acid media. An X-ray study of (Ph₃PAu)₃O⁺BF₄^- indicates that the oxonium ions are dimeric in the crystalline form. The fragment (Ph₃PAu)₃O has a pyramidal structure: the oxygen atom is outside the Au₃ plane.     

Ligand assisted homolytic cleavage of the Ru-Ru single bond in [Ru2(CO)4] core and the chemical consequence

The Ru-Ru single bond in [Ru₂(CO)₄(MeCN)₆][BF₄]₂ remains intact in the reaction with 2-i-propyl-1,8-naphthyridine (ⁱPrNP) and the isolated product is the cis-[Ru₂(ⁱPrNP)₂(CO)₄(OTf)₂] (1) obtained via crystallization in the presence of [n-Bu₄N][OTf]. The 2-t-butyl-1,8-naphthyridine (^tBuNP), on the contrary, leads to the oxidative cleavage of the Ru-Ru single bond resulting in the trans-[Ru(^tBuNP)₂(MeCN)₂][BF₄]₂[NC(Me)C(Me)N] (2). The anti-[NC(Me)C(Me)N]²⁻ is the product of the two-electron reductive coupling of two acetonitrile molecules. The phenoxo appendage in 2-(2-hydroxyphenyl)-1,8-naphthyridine (hpNP) brings the identical effect of the scission of the Ru-Ru bond but the process is non-oxidative and the product obtained is the cis-[Ru(hpNP)₂(CO)₂][BF₄] (3). The bis-(diphenylphosphino)methane (dppm) in dichloromethane oxidatively cleave the Ru-Ru bond leading to chloro bridged [Ru(μ-Cl)(dppm)(CO)(MeCN)]₂[BF₄]₂ (4). All the complexes have been characterized by the spectroscopic and electrochemical measurements and their structures have been established by X-ray diffraction study.     

Basic study on the determination of total boron by conversion to tetrafluoroborate ion (BF4) followed by ion chromatography

The basic study on the determination of tetrafluoroborate ion (BF₄⁻) by ion chromatography, and total boron by conversion of boric acid to BF₄⁻ followed by ion chromatography of BF₄⁻ has been carried out. The results of thermodynamic calculations for the system of boric acid (H₃BO₃)-F⁻-H⁺ showed that the mole fraction of BF₄⁻ was higher than 99% at pH lower than 3.5 and 4.5 when the total free fluoride concentration (2[H₂F₂] + 2[HF₂⁻] + [HF] + [F⁻]) was as high as 0.1 and 1.0 M, respectively. The fraction of BF₄⁻ increased with increasing total free fluoride concentration. BF₄⁻ fraction values were higher than 99% at pH 0.75 and at total free fluoride concentration of 0.05 M or higher. BF₄⁻ was hardly formed at pH > 7 even when the total free fluoride concentration was as high as 1.0 M. According to the experimental results, the fraction of BF₄⁻ at pH 0.7-0.8 was 51.2, 95.6 and 96.7% when the total fluoride concentration (2[H₂F₂] + 2[HF₂⁻] + [HF] + [F⁻] + 3[BF₃OH⁻] + 4[BF₄⁻]) was 0.2, 1.0 and 3.3 M, respectively. The formation reaction of BF₄⁻ from boric acid reached an equilibrium state within 20 min regardless of reaction temperature, in the range of 20-50 °C, when the total boron and total fluoride concentrations were 66.7 mM and 1.0 M, respectively. Although BF₄⁻ was formed only under acidic conditions, BF₄⁻, once formed, was very stable under alkaline conditions at least for several hours. We have concluded that BF₄⁻ could be analyzed by ion chromatography using sodium hydroxide solution as an eluent because BF₄⁻ was stable under chromatographic conditions. BF₄⁻ solution prepared from boric acid could be used as a standard solution in the ion chromatographic analysis of BF₄⁻ instead of the sodium tetrafluoroborate (NaBF₄) reagent available commercially, if a discrepancy of about 4-5% was allowed.     

Bis-phosphine monoxide platinum(II) and palladium(II) cationic complexes as Lewis acid catalysts in Diels-Alder and sulfoxidation reactions

A series of bis-phosphine monoxide (BPMO) palladium(II) and platinum(II) cationic complexes of the type [M(BPMO-κ²-P,O)₂][X]₂ (M = Pd, Pt; BPMO = Ph₂P-(CH₂)_n-P(O)Ph₂ with n = 1 (dppmO), 2 (dppeO), 3 (dpppO); X = BF₄, TfO) were prepared from the corresponding chlorides [MCl₂(BPMO-κ¹-P)₂] upon treatment with 2 equiv. of AgX in wet acetone/CH₂Cl₂ or MeOH solutions. They were characterized by ¹H and ³¹P{¹H} NMR spectroscopies and, in the case of the complex [Pt(dppeO-κ²-P,O)₂][BF₄]₂, also by X-ray crystallography. These complexes were tested as catalysts in some Diels-Alder and oxidation reactions with different substrates. In the latter reaction Pt(II) complexes showed moderate activity, while for the former one, both classes of complexes were active in the C-C coupling, in particular the Pt(II) species showed interesting high endo/exo diasteroselectivity depending on the counteranion.     

离子液体催化吲哚羟烷基化反应

报道了咪唑类离子液体催化吲哚和环状碳酸酯反应合成羟烷基吲哚,系统考察了反应时间、催化剂用量、反应温度和反应物比例对离子液体催化反应性能的影响.在优化的反应条件下,吲哚与碳酸乙烯酯或碳酸丙烯酯反应可高效地生成1-(2-羟乙基)吲哚、1-(2-羟丙基)吲哚及其相应的衍生物.离子液体的催化活性与离子液体中的阴离子有关,其催化活性顺序为BF₄^-﹤Br^-﹤Cl^-﹤OAc^-,与阴离子的碱度顺序一致.