噻唑衍生物电子光谱和二阶非线性光学性质的理论研究

采用量子化学密度泛函方法(DFT)在B3LYP/6-31G(d)水平上对有机二阶非线性光学生色团(E)-2-(5-(4-(双(4-甲氧苯基)氨基)苯乙烯基)噻唑-5)三氰乙烯(TPA-Ti2-TCV)(1)和(E)-2-(5-(4-(双(4-甲氧苯基)氨基)苯乙烯基)噻唑-2)三氰乙烯(TPA-Ti5-TCV)(2)进行几何构型的完全优化, 在优化所得构型的基础上, 采用含时密度泛函方法(TDDFT)在6-31G(d)基组水平上计算了电子吸收光谱的跃迁性质. 再采用有限场法(FF)在B3LYP/6-31G(d)水平上计算了分子的一阶超极化率β. 计算结果表明, 三芳胺在噻唑环上取代C5比取代C2有更大的一阶超极化率, 这是由于噻唑的区域化学性导致ΔE_HOMO-LUMO(TPA-Ti2-TCV)比ΔE_HOMO-LUMO(TPA-Ti5-TCV)大很多造成的.     

Solution Structure of One-Electron Reduced and Oxidized Molecules with Twisted Donor and Acceptor Moieties

The solution structures of the radical anion and the radical cation of the donor-acceptor molecules 3,4-di(1,3-dithiol-2-ylidene)-4-phenylbut-1-ene-1,1-dicarbonitrile ( 1 ) and 3,4-di(1,3-dithiol-2-ylidene)-4-phenylbut-1-ene-1,1,2-tricarbonitrile ( 2 ) are discussed based on cyclovoltammetric and ESR/ENDOR measurements. It is shown that the spin population of the radical anions is limited to the di- and tricyanoethene moiety and the coplanar 1,3-dithiole at C(3), whereas that of the radical cations resides mainly inside the two 1,3-dithiole rings. The energies of the long-wave bands in the electronic-absorption spectra of 1 and 2 correspond to the differences between the oxidation and reduction potentials and thus point to a charge-transfer character of these transitions.     

Metal-acetylide addition to tetracyanoethylene

Two push-pull chromophores that have shown utility in the field of molecular electronics and non-linear optics are DDMEBT (1, 2-(4-dimethylamino)phenyl)-3-((4-(dimethylamino)phenyl)ethynyl)buta-1,3-diene-1,1,4,4-tetracarbonitrile) and TDMEE (2, 4-(4-dimethylamino)phenyl)but-1-en-3-yne-1,1,2-tricarbonitrile). Unfortunately, the methods reported for their synthesis give variable yields, use toxic solvents, and only provide small amounts of material. We report improved synthetic protocols, providing access to larger quantities of material. By investigating multiple metal-acetylides of 4-ethynyl-N,N-dimethylaniline and their subsequent addition to TCNE, we obtained various products depending on the identity of the metal ion. This led to the simple synthesis of push-pull chromophoric compounds.     

Synthesis of heterocyclic compounds. XXIV. Synthesis of pyridines from β-substituted α-phenylacrylonitriles

The reaction of malononitrile with α-phenylcinnamonitriles in ethanolic sodium ethanethiolate is studied as a convenient route to 2-amino-4-aryl-5-cyano-6-ethylthio-3-phenyl-3,4-dihydropyridines ( 5 ) and the corresponding pyridines 6 . From the study of the structure of 5a (Ar = Ph) we can conclude that this cyclization reaction proceeds via a site-selective addition of the ethanethiolate to the cyano group i of the 1,3-tricarbonitrile ( 2 ).     

Synthesis and copolymerization of fluorinated monomers bearing a reactive lateral group. XX. Copolymerization of vinylidene fluoride with 4‐bromo‐1,1,2‐trifluorobut‐1‐ene

The radical copolymerization of vinylidene fluoride (VDF) with 4‐bromo‐1,1,2‐trifluorobut‐1‐ene (C₄Br) was examined. This bromofluorinated alkene was synthesized in three steps, which started with the addition of bromine to chlorotrifluoroethylene. In contrast to the ethylenation of 1,1‐difluoro‐1,2‐dibromochlorethane, which failed, that of 2‐chloro‐1,1,2‐trifluoro‐1,2‐dibromoethane was optimized and led to 2‐chloro‐1,1,2‐trifluoro‐1,4‐dibromobutane. The kinetics of the copolymerization of VDF with this brominated monomer initiated by t‐butyl peroxypivalate led to an assessment of the reactivity ratios, r_VDF = 0.96 ± 0.67 and r_C4Br = 0.09 ± 0.63, at 50 °C. The suspension copolymerization was also carried out, and the chemical modifications of the resulting bromo‐containing poly(vinylidene fluoride)s were attempted and consisted mainly of elimination or nucleophilic substitution of the bromine. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 917–935, 2005     

One-step synthesis of chromeno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridines

Three-component condensation of aliphatic aldehydes with resorcinol and malononitrile dimer (2-aminoprop-1-ene-1,1,3-tricarbonitrile) afforded the corresponding 5-alkyl-2,4-diamino-8-hydroxy-5H-chromeno[2,3-b]pyridine-3-dicarbonitriles.     

Chemical properties of <Emphasis Type="Italic">N</Emphasis>-polyfluoroethylimidazole and -pyrrole derivatives

Bromination, acylation, nitration, and metallation of imidazole and pyrrole derivatives containing the difluoromethylene fragment at the N atom were studied. 1-(1,1,2,2-Tetrafluoroethyl)pyrrole, 1-(1,1,2,2-tetrafluoroethyl)imidazole, and 1-(2-chloro-1,1,2-trifluoroethyl)imidazole were used as substrates. 1-Alkyl-3-(1,1,2,2-tetrafluoroethyl)- and 1-alkyl-3-(2-chloro-1,1,2-trifluoroethyl)imidazolium iodides were obtained. These can be used as intermediates for preparation of new ionic liquids of the imidazole series and 1-alkyl-3-polyfluoroethylimidazole-2-thiones.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 781–787, March, 2005.     

Reaction of Tetracyanoethylene with 2-Substituted Cyclohexanones

Reactions of 2-methylcyclohexanone and menthone with tetracyanoethylene gave 2-(1,1,2,2-tetracyanoethyl)cyclohexanones which underwent quantitative transformation in the solid phase into 3,4-cyanosubstituted 2-aminopyrans in 2-3 days at room temperature. 2-Methyl-2-(1,1,2,2-tetracyanoethyl)cyclohexanone reacted with hydroiodic acid to afford 8a-hydroxy-2-iodo-4a-methyl-1,4,4a,5,6,7,8,8a-octahydroquinoline-3,4,4-tricarbonitrile. The reaction of 2,2'-methylenedi(cyclohexanone) with tetracyanoethylene resulted in formation of 7-imino-4,5-tetramethylene-2'-oxo-6-oxabicyclo[3.2.1]octane-2-spiro-1'-cyclohexane-1,8,8-tricarbonitrile.     

Sequential Intramolecular Diels–Alder Reaction of 3‐Heteroaryl‐2‐propenylamides of Ethenetricarboxylate

The reaction of 1,1,2‐ethenetricarboxylic acid 1,1‐diethyl ester with E‐3‐(2‐furyl)‐2‐propenylamines under the amide condensation conditions (EDCI/HOBt/Et₃N) on heating at 80–110°C afforded cis‐fused tricyclic compounds, furo[2,3‐f]isoindoles as major product. On the other hand, the reaction with E‐3‐(3‐furyl)‐2‐propenylamines afforded trans‐fused tricyclic compounds predominantly. The formation of amide/[4 + 2] cycloaddition/hydrogen‐shift reactions proceed sequentially. The observed stereoselectivity of the fused rings has been investigated by the density functional theory calculations. The reaction of 1,1,2‐ethenetricarboxylic acid 1,1‐diethyl ester with 3‐(3‐pyridinyl)‐2‐propen‐1‐amine under the amide condensation conditions afforded HOBt‐incorporated 3,4‐trans‐pyrrolidine selectively. The chemoselectivity and stereoselectivity of the reactions with (3‐heteroaryl)‐2‐propen‐1‐amines depend on the nature of heteroarenes.     

Silver sequestration of halides for the activation of Pd(OAc)2 catalyzed Mizoroki‐Heck reaction of 1,1 and 1,2 ‐ Disubstituted alkenes

A ligand free catalytic system consisting of Pd(OAc)₂ (cat) and stoichiometric quantities of silver salts, AgOAc or AgBF₄, exhibit high efficiency in the Mizoroki‐Heck arylation, transforming aryl iodides and 1,1 as well as 1,2 disubstituted alkenes into 1,1,2 – trisubstituted aryl alkenes in excellent yields in very short reaction times.     

Three-component synthesis and optical properties of triarylpyridines containing a buta-1,3-diene-1,1,3-tricarbonitrile fragment

The synthesis of triarylpyridine derivatives containing a buta-1,3-diene-1,1,3-tricarbonitrile fragment via the base-promoted reactions of aromatic aldehydes, 2-phenylacetophenone and a malononitrile dimer in the presence of an oxidant is described. The influence of aryl substituents in the 4-position on the optical properties is also reported.     

Electrosynthesis of pyridines from ‘only acetonitrile’

2,4,6-Trimethylpyridine-3,5-dicarbonitrile has been obtained as the main product after the electrolysis of acetonitrile in the presence of tetrabutylammonium bisulfate as supporting electrolyte using a divided cell with a medium porosity diaphragm. 2,6-Dimethylpyridine-3,5-dicarbonitrile and 2,6-dimethylpyridine-3,4,5-tricarbonitrile have also been obtained in minor quantity. This process, which takes place with participation of both electrodes, is an example of a paired electrosynthesis.     

Cyclopropanation of alkynols with the CH<Subscript>2</Subscript>I<Subscript>2</Subscript>-R<Subscript>3</Subscript>Al system

Acetylenic alcohols bearing two or three methylene groups between the triple bond and hydroxy group react with CH₂I₂ in the presence of trialkylalanes to give 1,1,2-tri- and 1,1,2,2-tetrasubstituted cyclopropanes.     

Organocatalytic approach toward the green one-pot synthesis of novel benzo[<Emphasis Type="Italic">f</Emphasis>]chromenes and 12<Emphasis Type="Italic">H</Emphasis>-benzo[5,6]chromeno[2,3-<Emphasis Type="Italic">b</Emphasis>]pyridines

An efficient tandem reaction approach is described to prepare novel benzo[f]chromenes from 2,3-dihydroxynaphthalene, malononitrile and aldehydes using 10 mol% guanidine hydrochloride as the catalyst under solvent-free conditions. The method was also extended to the preparation of novel 12H-benzo[5,6]chromeno[2,3-b]pyridines from 2-aminoprop-1-ene-1,1,3-tricarbonitrile instead of malononitrile under the same reaction conditions. The described one-pot three-component reaction is characterized by short reaction times, high-product yield, mild reaction conditions, simple workup procedure, and simple purification.     

New push–pull chromophores. Synthesis of 2-[4-Aryl-3-cyano-5-hydroxy-5-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrrol-2(5<Emphasis Type="Italic">H</Emphasis>)-ylidene]malononitriles

2-Aminoprop-1-ene-1,1,3-tricarbonitrile (malononitrile dimer) reacted with 1-arylpropane-1,2-diones in ethanol in the presence of piperidine to give new donor–acceptor chromophores, 2-[4-aryl-3-cyano-5-hydroxy-5-methyl-1H-pyrrole-2(5H)-ylidene]malononitriles.     

Efficient and Green Method for the Synthesis of Highly Substituted Cyclohexadiene Derivatives in Aqueous Media

Three-component reaction of aromatic aldehyde, malononitrile, and 2-(1-(3-chlorophenyl)propylidene)malononitrile in aqueous media catalyzed by tetraethylbenzylammonium chloride (TEBAC) at 90 °C gave 2-amino-6-(3-chlorophenyl)-5-methyl-4-arylcyclohexa-1,5-diene-1,3,3-tricarbonitrile derivatives. The structure of 4e was further confirmed by x-ray diffraction. This three-component reaction had the advantages of green solvent, good yield, and operational simplicity.     

29Si nuclear magnetic resonance of dimethyl and phenylmethyl containing polysilanes

The ²⁹Si-NMR spectra are reported for poly(methylphenylsilylene), 1 , poly(1,1,2-trimethyl-2-phenyldisilene) 2 , two samples of poly(dimethylsilylene-co-phenylmethylsilylene), 3a and 3b , and poly(phenylmethylsilylene-co-n-hexylmethylsilylene), 4 . The spectra of 3a , 3b , and 4 indicate that these polymers contain blocklike regions with considerable segregation of RMeSi and PhMeSi groups. The spectrum of 2 shows no evidence for stereospecific polymerization. The preparation of 2 from 1,1,2-trimethyl-2-phenyldichlorosilane is also described.     

Methyl (<Emphasis Type="Italic">Z</Emphasis>)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate: Synthesis and reactions with dimethyl malonate and methyl acetoacetate

Bromination–dehydrobromination of methyl (E)-3-(4-methylbenzenesulfonyl)prop-2-enoate gave methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate whose structure was determined by X-ray analysis. Methyl (Z)-3-bromo-3-(4-methylbenzenesulfonyl)prop-2-enoate behaved as a synthetic equivalent of methyl 3-(4-methylbenzenesulfonyl)prop-2-ynoate in reactions with dimethyl malonate and methyl acetoacetate, which afforded the corresponding Michael adducts, trimethyl 3-(4-methylbenzenesulfonyl)prop-1-ene-1,1,2-tricarboxylate and dimethyl (Z)-2-acetyl-3-(4-methylbenzenesulfonyl)but-2-enedioate, respectively, via nucleophilic attack on the β-position with respect to the sulfonyl group.     

Syntheses with nitriles. 62. 3,5-Dicyanopyridine derivatives by vilsmeier formylation of malononitrile and tetracyanopropenides

Reaction of malononitrile with dimethylformamide and phosphorus oxychloride gave (dimethylamino-methylene)malononitrile ( 1 ), 4-chloro-7-methyl-5,7-diaza-1,3,5-octatriene-1,1,3-tricarbonitrile ( 3a ) and the pyridine 2 . Compounds 3a and 3b as well as the triaza-derivative 3c may also be obtained by treatment of tetracyanopropenides 4a-c with dimethylformamide and phosphorus oxychloride. Ring closures were achieved by heating 3 under alkaline or acidic conditions. Substitution of chlorine in 3a with aromatic amines provided 1-aryl-1,2-dihydro-2-imino-3,5-pyridinedicarbonitriles 7 . Hydrolysis of 7 gave the 2-oxo-derivatives 8 .     

Reaction of Perfluorobenzocyclobutene with Excess Pentafluorobenzene in SbF<Subscript>5</Subscript>

The reaction of perfluorobenzocyclobutene with excess pentafluorobenzene in SbF₅, followed by hydrolysis, gave a mixture of perfluoro-1,3,3-triphenyl-1,3-dihydro-2-benzofuran-1-ol, perfluoro-1,1,2-triphenylbenzocyclobuten- 5-one, and perfluoro-4-(2,2-diphenylbenzocyclobuten-1-ylidene)cyclohexa-2,5-dien-1- one. When the reaction mixture was treated for a long time with Olah’s reagent (HF–pyridine), isomeric perfluoro-9,10-diphenyl-1,4-, -1,10-, -2,9-, and -9,10-dihydroanthracenes were formed and were converted to perfluoro-9,10-diphenylanthracene by the action of SbF₅.