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21.
In this study, a novel donor-acceptor type monomer was designed based on selenophene and benzotriazole with a bulky pendant group and synthesized through Stille coupling reaction. The monomer was polymerized electrochemically by using cyclic voltammetry and also chemically by oxidation in the presence of FeCl3. Both polymers were then compared in terms of their optical properties, electrochemical and spectroelectrochemical behaviors, kinetic and colorimetric properties and surface morphologies. Independent of the polymerization method, both electrochemically (E-PSeBTz) and chemically polymerized (C-PSeBTz) coatings showed quite similar properties. Both polymers have p-doping character and multichromic properties in their oxidized states. The polymers can be fully switched between their oxidized and neutral states in fairly short times with acceptable optical contrast at different wavelengths. Both polymers exhibit a λmax of 505?nm and the optical band gaps of the materials were found to be 1.85?eV and 1.80?eV for E-PSeBTz and C-PSeBTz, respectively. 相似文献
22.
L. I. Belen'kii T. G. Kim I. A. Suslov N. D. Chuvylkin 《Russian Chemical Bulletin》2005,54(4):853-863
Data on the relative reactivities (substrate selectivity) of five-membered heterocycles in electrophilic substitution reactions
and positional selectivity (α : β ratio) in these reactions were analyzed. Unlike the substrate selectivity (pyrrole ≫ furan
> selenophene > thiophene) determined by the position of heteroatoms in the Periodic Table, the positional selectivity decreases
in the order corresponding to the change in the relative stability of the onium states of the elements (O+ < Se+ ≤ S+ < N+) and reflects the predominant role of heteroatoms in the stabilization of σ complexes formed upon β-substitution. These differences
in the positional selectivity of the parent heterocycles have a substantial effect on the orientation in electrophilic substitution
reactions in their derivatives and the corresponding benzoannelated systems. This interpretation was confirmed by ab initio quantum chemical calculations (RHF/6–31G(d) and MP2/6– 31G(d)//RHF/6–31G(d)) and density functional theory calculations (B3LYP/6–31G(d)).
Quantum chemical calculations were performed by the above-mentioned methods for model N-R-pyrroles (R = Me, Et, Pri, But, CH=CH2, C≡CH, Ph, PhSO2, and 4-O2NC6H4) and their α- and β-protonated σ complexes. The results of these calculations demonstrated that it is the steric factors
and charges on the β-C, α-C, and N atoms and the substituents at the N atom (the kinetic control), as well as the nature of
the electrophile, rather than the difference in the relative stabilities of the onium states of N+ (which depends on the nature of the substituent at the N atom and reflects the role of the heteroatom in stabilization of
σ complexes formed via β-substitution; the thermodynamic control) that are responsible for the type of orientation (α or β) that prevails.
Dedicated to Academician V. I. Minkin on the occasion of his 70th birthday.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 837–846, April, 2005. 相似文献
23.
Dimitri I. Kochubey Vladimir A. Rogov Vera P. Babenko 《Reaction Kinetics and Catalysis Letters》2007,90(1):167-177
The rate of thiophene decomposition was shown to be independent of the type of chalcogens used in catalysts MoX2/Al2O3, where X = S, Se. On the contrary, the rate of selenophene decomposition was shown to be higher on catalysts MoSe2 than that on MoS2. This observation suggests that the decomposition proceeds on anion vacancies. The decomposition of either thiophene over
MoSe2 or selenophene over MoS2 results in the formation of partially substituted chalcogenides. At that, the molar ratios of the substituted chalcogen to
Mo were shown to coincide in both cases. The fact that the rate of the thiophene decomposition does not depend on the degree
of anion exchange indicates that the decomposition is not associated with hydrogenolysis. 相似文献
24.
Metin YILDIRIM Mehmet ERSATIR Badel ARSLAN Elife Sultan GRAY 《Turkish Journal of Chemistry》2021,45(1):192
3-acetyl coumarin derivatives (1a-d) are formed as a result of condensation of salicylaldehyde derivatives and ethyl acetoacetate and were converted into coumarin-selenophene hybrid compounds (2a-d) in the basic medium by modified Gewald reaction in the presence of malononitrile and selenium. Products are characterized by nuclear magnetic resonance (NMR). The prepared compounds are screened for their anticancer activity against DU-145 cell line. In addition, selected target compounds are evaluated for apoptosis and oxidative stress on DU-145 (prostate carcinoma) cell lines. 相似文献
25.
A. B. Trofimov I. L. Zaitseva T. E. Moskovskaya N. M. Vitkovskaya 《Chemistry of Heterocyclic Compounds》2008,44(9):1101-1112
The ionization spectra of furan, pyrrole, thiophene, and selenophene have been calculated within the framework of the nonempirical
quantum-chemical method with the Green's one-particle function in the approximation of the third order algebraic diagram construction
[ADC(3)]. The calculated energies and the intensity of vertical transitions pertaining to the ionization of outer and inner
shells are compared with the newest experimental data. The good agreement of theoretical and experimental results enabled
a detailed assignment and interpretation of the observed photoelectron spectra to be carried out. Problems of disturbing the
picture of orbital ionization are considered; the mechanism of formation of low-lying photoelectron satellites is explained.
Certain general rules and trends of the behavior of the spectra of the systems studied are considered.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1366–1379. September, 2008. 相似文献
26.
P. Amaladass 《Tetrahedron》2008,64(34):7992-7998
A series of 1,3-diarylbenzo[c]selenophenes (symmetrical/unsymmetrical) have been synthesized involving a selenium transfer reaction of keto-alcohol/benzo[c]furan using Woollins reagent. The optical and electrochemical studies of these diarylbenzo[c]selenophenes are correlated with their structures. 相似文献
27.
In this study, two new conjugated polymers were synthesized including benzotriazole (BTz) as the acceptor unit and selenophene as the π bridge donor segment. These acceptors were coupled with fluorene and carbazole via Suzuki condensation reactions. Electrochemical band gaps were calculated as 2.45 eV for P1 and 2.40 eV for P2. Electrochemical and optical studies of polymers indicate that both polymers are promising candidates for organic solar cell (OSC) and polymer organic light emitting diode (PLED) applications since they have suitable HOMO-LUMO energy levels and appropriate absorption and emission band ranges. Light emitting properties of synthesized polymers were investigated and the highest luminance value was found as 6608cd/m2 for P1 at 8 V. Photovoltaic properties of polymers were investigated and the optimized device based on P2 showed 1.75% power conversion efficiency for P2 under AM 1.5 G illumination at 100 mW/cm2. 相似文献
28.
The literature data concerned with thermal reactions producing thiophene, selenophene, and their derivatives are systematized and reviewed. The mechanisms of these reactions are examined and conditions for the formation of thiophene and selenophene heterocycles are formulated.Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk 664039, Russia; e-mail: vlad@irioch.ira.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 3–18, January, 2000. 相似文献
29.
The DFT/B3LYP/6-31G* method is used in an anharmonic approximation to analyze the vibrational spectra of substituted furan,
thiophene, and selenophene (3,4- and 2,5-dimethyl-, dichloro-, and diaza-; and 2,3,4,5-tetrachloro-). The influence of resonance
effects is clarified.
in final form, December 16, 2008.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 2, pp. 170–175, March–April 2009. 相似文献
30.