1,2-双[2-甲基-5-(3,4-二氟苯基)噻吩-3-基]全氟环戊烯的合成

在冰浴条件下, 2-甲基噻吩(1)与液溴反应生成3,5-二溴-2-甲基噻吩(2); 在－78 ℃条件下, 硼酸三丁酯加入2, 得到2-甲基-3-溴-5-硼酸基噻吩(3); 3,4-二氟溴苯与3反应得到2-甲基-3-溴-5-(3,4-二氟苯基)噻吩(4); 在－78 ℃下全氟环戊烯与4反应, 得到一种新的二芳基乙烯类光致变色化合物1,2-双[2-甲基-5-(3,4-二氟苯基)噻吩-3-基]全氟环戊烯(DT-1). 用IR, NMR, MS和元素分析确定了化合物DT-1的结构, 并对该化合物的光致变色特性进行了初步研究.     

Liquid crystalline behavior and fluorescent property of calix[4]arene containing azobenzene photochromic group

The reaction of 4′-hydroxy-4-methyl azobenzene (1) and 1,6-dibromohexane afforded 6-bromo-1-((4-((4-met hylphenyl)azo)phenyl)oxy)hexane (2), which further reacted with p-tert-butylcalix[4]arene to give the calix[4]arene derivative (3) whose lower rim had been modified by the azobenzene photochromic group. The structure of 3 was characterized by ¹H-nuclear magnetic resonance (NMR) and electrospray ionization-mass spectrometry (ESI-MS). The fluorescence intensity of compound 3 was two to four times higher than that of compounds 1 and 2 as the azobenzene group concentration in the range of 1.6 × 10⁻⁵ to 8.0 × 10⁻⁴ mol/L, indicating that the fluorescence quantum yield of the azobenzene group had been improved through being attached to the calix[4]arene skeleton. The liquid crystalline behavior of compound 3 was studied by polarized microscopy (POM) and differential scan calorimeter (DSC). Compound 3 exhibited the enchased texture of a smectic liquid crystal from 209.4°C to 219.5°C on heating, while 2 exhibited a liquid crystalline phase from 87.4 to 83.2°C on cooling. It was found that the calix[4]arene skeleton was a good platform for conformation immobilization of azobenzene photochromic group and the formation of liquid crystalline. Translated from Chinese Journal of Applied Chemistry, 2006, 23(9): 1023–1026 [译自: 应用化学]     

Photochromic dihetarylethenes

The structures of two hetarylethene photochromes,viz., 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene, were established by X-ray diffraction analysis. The conformational parameters of the title compounds are considered. The cyclopentene ring in the former compound is planar and this ring in the latter compound adopts an envelope conformation. There are no overall conjugated systems in the molecules under study. In both structures, the dihetaryl fragments are rotated with respect to the perfluorocyclopentene fragments by ∼55°. The thiophene and benzoxazole rings in 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene are coplanar. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–77, January, 2000.     

Investigation on photochromism of 1,2-bis(1,4-dimethyl-2-phenyl)perfluorocyclopentene

The photochromic diarylethene, 1,2-bis(1,4-dimethyl-2-phenyl)perfluorocyclopentene has been synthesized and its single crystal can be obtained in hexane at -4℃. The structure of diphenylperluorocyclopentene bearing C2/c space group and monoclinic crystal system is very different from that of dithienylperfluorocyclopentene derivatives bearing Pī space group and triclinic crystal system by X-ray crystallographic analysis. The compound undergoes the phototchromic reaction in solution but no optical activity in single crystal. In addition, its optimum conformation in solvent is also discussed.     

Photochromic dihetarylethenes

The structures of two hetarylethene photochromes,viz., 1,2-bis(2-ethyl-5-ethylsulfonylthien-3-yl)perfluorocyclopentene and 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene, were established by X-ray diffraction analysis. The conformational parameters of the title compounds are considered. The cyclopentene ring in the former compound is planar and this ring in the latter compound adopts an envelope conformation. There are no overall conjugated systems in the molecules under study. In both structures, the dihetaryl fragments are rotated with respect to the perfluorocyclopentene fragments by ∼55°. The thiophene and benzoxazole rings in 1,2-bis[5-(benzoxazol-2-yl)-2-methylthien-3-yl]perfluorocyclopentene are coplanar. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 74–77, January, 2000.     

GC-FID optimization and validation for determination of 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine and methamphetamine in ecstasy tablets

A methodology for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in seized tablets using gas chromatography with a flame ionization detector (GC-FID) is described. The chromatographic conditions, i.e. gas flow rates and temperatures for the column, injector and detector were optimized. The optimum chromatographic conditions were as follows: a CP-SIL 24 CB WCOT fused silica capillary column (30 m × 0.32 mm I.D., 0.25 μm film thickness), N₂ carrier gas flowing at 2.6 mL/min, injector temperature at 290°C and detector temperature at 300°C. The oven temperature was ramped from 80°C at a rate of 20°C/min to final temperature of 270°C (1 min). All analytes were well separated within 7 min with an analysis time of 10.5 min. Calibration curves were linear over the concentration ranges of 3.125–200 μg/mL for MDMA and 6.25–200 μg/mL for MDA and MA (r > 0.990). The intra- and inter-day precisions for determining all analytes were 2.32–10.38% RSD and 1.15–9.77% RSD, respectively. The intra- and inter-day accuracies ranged from −19.79 to +17.51% DEV and −6.84 to +5.2% DEV, respectively. The lower limits of quantification (LLOQs) were 3.125 μg/mL for MDMA and 6.25 μg/mL for MDA and MA. All analytes were stable at room temperature during 24 h but significant loss occurred after 2-month storage at −20°C. The method was shown to be useful for determining the purity of MDMA in seized tablets.     

The allomorphism of a photochromic diarylethene

The photochromic diarylethene, 1,2-bis(2-methyl-5-(2,2′-dicyanovinyl)-thien-3-yl)perfluorocyclopentene (1a), was synthesized by a novel method. Two kinds of single crystals of the compound were obtained depending on the different recrystallization conditions and their structures were determined by X-ray crystallographic analysis. Allomorphism of the photochromic diarylethene was discovered. The compound underwent a photochromic reaction both in solution and in the single crystalline phase of the anti-parallel conformer.     

Alkynylhalocarbenes

(Alk-1-ynyl)chlorocarbenes (3), generated from 1,1-dihaloalk-2-ynes and 3-substituted 3-bromo-1,1,1-trichloropropanes under the action of Bu^tOK in THF at 20°C, react with excess alkali metal alkoxide4 to give 3-substituted 2-(alk-1-ynyl)oxiranes (6) in 26–78% yields, most likely as a result of insertion of carbene3 into the α-C−H bond of alkoxides4 and subsequent cyclization of the resulting 1-substituted 2-chloro-2-(alk-1-ynyl)etoxides. The yields of oxiranes6 depend on the nature of the alkali metal used to prepare alkoxides4 and on the method employed for the preparation of the latter. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1185–1192, June, 1998.     

Synthesis and structure of cobalt complexes [Me3EtN] 2+ [CoI4]2? and [Me3BuN] 2+ [CoI4]2?

Complexes [Me₃EtN]₂⁺[CoI₄]²⁻ (I) and [Me₃EtN]₂⁺[CoI₄]²⁻ (II) were synthesized by reacting trimethylalkylammonium iodide with cobalt(II) iodide in acetone. According to X-ray diffraction data, complexes I and II consist of tetrahedral tetraalkylammonium cations (for I, N-C is 1.481(5)–1.590(8) CNC is 107.3(3)°–111.6(3)°; for II, N-C is 1.485(8)–1.506(10) ? and CNC is 106.9(7)°–111.7(5)°) and [CoI₄]²⁻ anions (for I, Co-I is 2.5951(5)–2.6127(5) ? and ICoI is 104.67(2)°–113.23(2)°; for II, Co-I is 2.5914(8)–2.5943(9) ? and ICoI is 107.05(2)°–114.42(5)°).     

A proton and optic dual-control molecular switch based on photochromic diarylethene bearing a rhodamine unit

A novel fluorescent switch based on rhodamine B and photochromic diarylethene, 1-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]-2-[2-methyl-5-(4-rhodamine B hydrazine-Schiff base-phenyl)-3-thienyl]perfluorocyclopentene (1), has been successfully synthesized through the condensation of rhodamine B hydrazine and 1-[2-methyl-5-(4-methoxylphenyl)-3-thienyl]-2-[2-methyl-5-(4-formylphenyl)-3-thienyl]perfluorocyclopentene. UV and FL measurements reveal that the compound exhibits good photochromic properties responsive to proton and optic dual inputs. Upon irradiation with 297 nm light, the colorless solution of compound 1 turns blue, while the blue solution becomes colorless after irradiated with visible light (λ>450 nm). Furthermore, upon an addition of H⁺, the fluorescence resonance energy transfers from the rhodamine unit (FRET donor) to the closed-ring diarylethene unit (FRET acceptor), although no energy transfer occurs when the diarylethene is in the open-ring form. The emission intensity of the rhodamine can be modulated with proton and UV/vis light and molecular-level signal communication has been constructed, indicating high potentials of the compound in molecular switches or naked eye recognition systems.     

Thermal decomposition paths in A<Subscript>2</Subscript>CuCl<Subscript>4</Subscript> complexes: anilinium and its derivatives

The thermal decomposition paths of anilinium, 4-chloro anilinium tetrachlorocopper(II) complexes are compared to their benzilinium derivative. All these complexes crystallize in the layered structure, typical for a A₂MX₄ family, are studied in literature for their magnetic, semiconducting properties. TG analyses of (anilinium)₂CuCl₄ (A) and (4-chloro anilinium)₂CuCl₄ (B) loses one molecule of organic ammonium hydrochloride along with one molecule of amine, to form (H)CuCl₃, which subsequently completely decomposes to Cu above 500 °C. On the other hand, (benzilinium)₂CuCl₄ (C) loses two molecules of hydrochloride along with chlorine molecule first then two molecules of benzyl amine with formation of Cu above 300 °C. DSC studies on C have shown reversible endothermic phase transition at 130.95 °C (−1.98 J g⁻¹) while heating and exothermic phase transition at 117.07 °C (0.93 J g⁻¹) while cooling. Thus, the observed changes in the decomposition pathway can be correlated to the order–disorder phase transition occurred in the compound C.     

Syntheses and optoelectronic properties of four photochromic dithienylethenes

Four photochromic dithienylethene compounds, 1,2-bis(2-methyl-5-naphthalene-3-thienyl)perfluorocyclopentene 1a, 1,2-bis[2-methyl-5(p-fluorophenyl)-3-thienyl]perfluorocyclopentene 2a, 1,2-bis[2-methyl-5(p-ethoxyphenyl)-3-thienyl]perfluorocyclopentene 3a, and 1,2-bis[2-methyl-5(p-N,N-dimethylaminophenyl)-3-thienyl]perfluorocyclopentene 4a were synthesized, and their optoelectronic properties, such as photochromism in solution as well as in poly-methylmethacrylate (PMMA) amorphous films, fluorescences and electrochemical properties were investigated in detail. These dithienylethenes have shown good photochromic behavior both in solution and in PMMA amorphous film. All of them exhibited relatively strong fluorescence and gave a bathochromic shift upon increasing concentration in THF. The irreversible anodic oxidation of 1a, 2a and 4a was observed by performing cyclic voltammetry experiments.     

Photochromic dihetarylethenes

A series of new photochromic compounds were obtained for the first time from 1,2-bis(2-ethylthio-3-thienyl)perfluorocyclopentene by substituting bromine atoms or carboxy, alkoxycarbonyl, and carbamoyl groups for hydrogen atoms in positions 4 and 4′. Introduction of these substituents causes a slight bathochromic shift (by 20–30 nm) of a long-wavelength absorption band for the cyclic form and significantly increases the quantum yields of photocyclization Ф_A→B and ring opening Ф_B→A. Depending on the nature of a substituent, Ф_A→B decreases in the order COOH>COOMe>CONHAr. The quantum yields are markedly reduced when the ethylthio groups in positions 5 and 5′ are replaced by ethylsulfonyl groups (a tenfold reduction in Ф_A→B and a four- to fivefold reduction in Ф_B→A) The most considerable bathochromic shift of a long-wavelength band and the highest quantum yields of forward and reverse photoreactions were observed for 1,2-bis(4-bromo-2-ethylthio-3-thienyl) perfluorocyclopentene. 1,2- Bis (2-ethyl-5-ethylthio-4-methoxycarbonyl-3-thienyl)perfluorocyclopentene was structurally characterized by X-ray diffraction analysis.     

Heterocyclization of ω-Bromo-2-trichloroacetyl Cycloalkanones to Isoxazole Derivatives

A new series of brominated 3,4-polymethylene-5-hydroxy-5-trichloromethyl-4,5-dihydroisoxazoles (2a–d) has been regiospecifically obtained from the reaction of ω-bromo-2-trichloroacetylcycloalkanones with hydroxylamine in 79–87% yield. Dehydration of the 5-hydroxydihydroisoxazoles 2a–d can be effected with concentrated sulfuric acid at 25 °C to give the regioisomeric brominated 3,4-polymethylene-5-trichloromethylisoxazoles (3a–d). In contrast, the dehydration of 5-hydroxydihydroisoxazoles with sulfuric acid in ethanol solution at 65 °C, for transformation of trichloromethyl to carboxyl group, was reproducible only with 9-bromo-3-trichloromethyl-3,3a,4,5,6,7,8,9-octahydrocycloocta[c]isoxazole-3-ol, 2d, leading to isoxazolecarboxylate 4d. The structural assignments of all isolated products are based on the analysis of their ¹H and ¹³C NMR spectral data.     

Kinetic and mechanism of alkene polymerization

Triphenylmethyl salts of the very weakly-coordinating borate anions [CN{B(C₆F₅)₃}₂]⁻ (1), [H₂N{(C₆F₅)₃}₂]⁻ and [M{CNB(C₆F₅)₃}₄]²⁻ (M = Ni, Pd) have been prepared in simple one-pot reactions. Mixtures of (SBI)ZrMe₂/1/AlBu ₃ ⁱ (SBI = rac-Me₂Si(Ind)₂) are 30–40 times more active in ethylene polymerizations at 60–100°C than (SBI)ZrCl₂/MAO. The quantification of anion effects on propene polymerization activity at 20°C gives the order [CN{B(C₆F₅)₃}₂]⁻ > [H₂N{(C₆F₅)₃}₂]⁻ ≈ B(C₆F₅) ₄ ⁻ ≫ [MeB(C₆F₅)₃]⁻. The highest productivities were of the order of ca. 3.0 × 10⁸ g PP (mol Zr)⁻¹ h⁻¹ [C₃H₆]⁻¹, about 1.3–1.5 times higher than with B(C₆F₅) ₄ ⁻ as the counter anion. The titanium system CGCTiMe₂/1/AlBu ₃ ⁱ gave activities that were very similar to the zirconocene catalyst. The concentration of active species [C*] as determined by quenched-flow kinetic techniques indicates typical values of around 10%, independent of the counter anion, for both the borate and MAO systems. Pulsed field-gradient spin echo and nuclear Overhauser effect NMR experiments on systems designed to be more realistic models for active species with longer polymeryl chains, (SBI)M(CH₂SiMe₃)(μ-Me)B(C₆F₅)₃ and [(SBI)MCH₂SiMe ₃ ⁺ ...B(C₆F₅) ₄ ⁻ ] (M = Zr, Hf), demonstrated the influence of bulky alkyl chains on the ion pair solution structures: while the MeB(C₆F₅)₃ compound exists as a simple inner-sphere ion-pair, the B(C₆F₅) ₄ ⁻ compound is an outer-sphere ion pair (OSIP), a consequence of the relegation of the anion into the second coordination sphere by the γ-agostic interaction with the alkyl ligand. The OSIP aggregates to ion hextuples (10 mM) or quadruples (2 mM). Implications for the polymerization mechanism are discussed; the process follows an associative interchange (I _a) pathway. The text was submitted by the authors in English.     

Structure and photochromic properties of a single-crystalline spiro[indolinepyranopyridinium] salt

The molecular and crystal structure of single crystalline 5’-hydroxymethyl-1,3,3,7’, 8’-pentamethylspiro[indoline-2,2’-[2H]-pyrano[3,4-b]pyridinium] iodide (1) was studied. The crystal structure is composed of cation layers separated by iodide ions and provides a sufficient volume for the phototransformation of compound 1. The spectroscopic and photochromic properties of this compound in the crystalline state were investigated. Upon irradiation with light at 270–370 nm, up to 600 layers of single crystals are subjected to photochromic transformations. The quantum yield of formation of the open form is ∼0.1, and the quantum yield of decoloration is 0.04. After ten reversible photocyclizations, the absorption of the colored form was decreased by 10%. The photochromic properties were related to the single-crystal structure. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2050–2055, September, 2005.     

Thermal decomposition product of 1,2-bis(2-methyl-1-benzofuran-3-yl)perfluorocyclopentene

1,2-Bis(2-methyl-1-benzofuran-3-yl)perfluorocyclopentene shows photochromism in n-hexane at room temperature. We have identified a new compound produced by the thermal decomposition in a mixture of cis- and trans-decahydronaphthalene above 100?°C in the absence of light.     

Natural product chemistry,Part 132: Synthesis and oxidative cyclisation of 1,3-dihydroxy-10-methyl-4-(3-methylbut-2-enyl)-9(10H)-acridinone (glycocitrine-II)

Summary Reaction of 1,3-dihydroxy-10-methyl-9(10H)-acridinone (1) and 1-bromo-3-methylbut-2-ene (mol. ratio 1:1) in tetrahydrofuran at 20°C in the presence of alumina gave prenylacidinones2 (glycocitrine-II) and8 and the diprenylacridinone9; with an excess of 1-bromo-3-methylbut-2-ene, the prenyldihydropyranoacridinones12 and13 were formed. Oxidation of glycocitrine-II (2) withm-chloroperbenzoic acid furnished the furanoacridinone5 and the pyranoacridinone6; dehydration of the latter compound gave noracronycine (10).(the late)     

Synthesis, crystal structure, and reduction of bis(2-phenylindenyl)hafnium dichloride

Reduction of the bent-sandwich [·⁵-(Ph)Ind]₂HfCl₂ complex (1) (where (Ph) Ind is the 2-phenylindenyl anion) in a THF medium was studied by low-temperature cyclic voltammetry. Complex1 is stable in THF at a temperature lower than −50°C and undergoes reversible one-electron reduction to radical anion1 ^{. −}. Further one-electron reduction of1 ^{. −} to dianion1 ²⁻ is accompanied by the elimination of two Cl⁻ ions to form the bisindenyl sandwich [·⁵-(Ph)Ind]₂Hf complex (2). This complex can undergo reversible one-electron reduction to the corresponding radical anion2 ^{. −}, which is stable within the cyclic voltammetry time scale. AtT=−30°C in a THF solution, complex1 was reduced to a diamagnetic (apparently, binuclear) Hf^III complex, which was characterized by cyclic voltammetry. Synthesis and the crystal structure of complex1 are reported. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2161–2165, December, 1997.     

Novel Copolymers of Styrene. 17. Ring-Trisubstituted Methyl 2-Cyano-3-Phenyl-2-Propenoates

Electrophilic trisubstituted ethylenes, ring-trisubstituted methyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO₂CH₃ (where R is 2,4,6-trimethyl, 3,5-dimethoxy-4-hydroxy, 3,5-dimethyl-4-hydoxy, 3,4,5-trimethoxy, 2-bromo-3-hydroxy-4-methoxy, 5-bromo-2,3-dimethoxy, 5-bromo-2,4-dimethoxy, 6-bromo-3,4-dimethoxy were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-trisubstituted benzaldehydes and methyl cyanoacetate, and characterized by CHN analysis, IR, ¹H and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r₁) for the monomers is 5-bromo-2,3-dimethoxy (2.69) > 3,4,5-trimethoxy (1.86) > 6-bromo-3,4-dimethoxy (0.84) > 5-bromo-2,4-dimethoxy (0.39) > 4-hydoxy-3,5-dimethyl (0.31) = 2-bromo-3-hydroxy-4-methoxy (0.31) > 3,5-dimethoxy-4-hydroxy (0.24) > 2,4,6-trimethyl (0.22). Relatively high T_g of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500ºC range with residue (1–6% wt), which then decomposed in the 500–800ºC range.