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1.
球烯C60与锌酞菁形成电荷迁移络合物的研究   总被引:6,自引:3,他引:6  
球烯是一种很有前途的新型非线性光学材料,它具有非平面的共轭离域大Π键体系,具有结合电子的能力,可作为电子受体与电子给体形成电荷迁移络合物(CTC),并能改善有机分子的光学和电学性质[1~4].金属酞青(MPc)也具有共轭大Π键体系,富有π电子,且具有良好的光敏性、化学稳定性及热稳定性.在一定条件下,球烯与金属酞育形成的CTC将大大改善金属酞育的光电性能.因此,研究球烯与金属酞蓄形成的CTC对开拓球烯与金属酞警的应用有重要意义.本文根据C60与锌酞菁(ZnPc)形成的CTC的光谱特征对其组成及相应的平衡常数进行了研究…  相似文献   

2.
A vinyl monomer having an electron-donating moiety, p-(N,N-dimethylamino)styrenc (DMAS),was synthesized. It was combined with benzoyl peroxide (BPO) to form a redox initiation system to initiatethe polymerization of methyl methacrylate (MMA). UV spectra measurements show that DMAS enters thePMMA chain as well. Both DMAS and its polymer P(DMAS) display strong fluorescence, and thefluorescence can be quenched by electron-deficient compounds such as methacrylonitrile, fumaronitrile andmethyl methacrylate etc. Moreover, DMAS can also form charge transfer complex (CTC) with strongelectron acceptors such as tetracyanoethylene (TCNE). The difference between the photochemical propertiesof DMAS and P(DMAS) were explained in terms of molecular structure change and polymer conformationeffect in solution. In addition, the CTC and exciplex formation of DMAS or P(DMAS) with C_(60) were alsostudied.  相似文献   

3.
C_(60)与含受电子生色基团聚合物的电荷转移现象   总被引:2,自引:0,他引:2  
C60与含受电子生色基团聚合物的电荷转移现象邱健姚光庆周锡煌李福绵(北京大学化学与分子工程学院北京100871)关键词C60,聚[N (4 氰基苯基)丙烯酰胺],电荷转移现象,荧光光谱随着对球壳烯性质的深入认识,球壳烯与电子给、受体的电荷转移现象日...  相似文献   

4.
用IR和UV两种方法首次研究了吩噻嗪与7个酸酐形成的电荷转移络合物,测定了它们的组成和溶剂效应,并推测出酸酐与吩噻嗪形成电荷转移络合物时相互作用的方式(结构)。  相似文献   

5.
电子给体(D)和电子受体(A)在基态下所形成的电荷转移络合物(CTC),在有机反应、催化、高分子等的理论及应用研究方面具有重要意义,故受到广泛地注意[1-2]。分子间形成CTC的过程伴有电荷分布的变化,故往往可观察到与该过程相应的电荷转移吸收光谱。  相似文献   

6.
用电化学石英晶体微天平(EQCM)研究了高氯酸溶液中电位环扫过程中邻(间、对)苯二酚/醌电荷转移配合物(CTC)的生成和电沉积。结果发现,邻(对)苯二酚可产生CTC并在电极上沉积,而间苯二酚仅发生电聚合反应。以邻苯二酚为例考察了高氯酸和邻苯二酚浓度及电位扫描速度的影响。红外光谱证实了邻苯二酚/醌CTC的生成。结果发现,添加肝素钠对邻苯二酚/醌CTC的沉积有显著影响,肝素钠质量浓度分别低/高于0.05 g/L时,能增强/减弱沉积现象。EQCM技术可作为一种快速、简便、灵敏的工具可望用于CTC制备过程中的实时监测和筛选。  相似文献   

7.
用膨胀计法研究了西氯苯醌(CA)、苯醌(BQ)与受阻胺二异丙胺(DIPA)、2,2,6,6-四甲基-4-羟基哌啶(TMP)形成的电荷转移络合物(CTC)对偶氮二异丁腈(AIBN)引发的甲基丙烯酸甲酯(MMA)自由基聚合阻聚效应。结果表明,CA-DIPA、CA-TMP、BQ-DIPA和BQ-TMP对MMA的自由基聚合均产生较单独的醌或胺更显著的阻聚能力。其中以CA-DIPA阻聚效果更佳。比较了MMA在苯或乙腈中的溶液聚合,得类似结果。初步讨论了受阻胺-醌电荷转移络合物对MMA自由基聚合的阻聚反应机理。  相似文献   

8.
The reaction of vinylindole with bromine, chlorine, and iodine in CCl4 solution in the cold leads to the formation of charge-transfer complexes (CTC). The formation of CTC has been confirmed by a study of the physicochemical properties and the IR and UV spectra of the reaction products.  相似文献   

9.
Three basic conditions for preparation of alternating copolymer with narrow molecular weight distribution were derived from the element kinetic equations of binary radical copolymerization. Using maleimide (MI) and atropie acid (ATA) as model monomer pairs and dioxane as the solvent the alternating copolymer with molecular weight distribution in the range of 1.09--1.20 was prepared successfully by charger transfer complex (CTC) mechanism in the presence of benzoyl peroxide at 85℃. The monomer reactivity ratioes r_1(MI)=0.05±0.01 and r_2(ATA)=0.03±0.02 were measured. The alternating eopolymerization was carried out through formation of a contact-type CTG and then alternating addition of MI and ATA monomers. The molecular weight of the copolymers is nearly independent of the feed ratio in a large range and the polymerization rate dropped with an increase in ATA in feed ratio.  相似文献   

10.
The veterinary antibacterial agents chlortetracycline (CTC), oxytetracycline (OTC), sulfadiazine (SDZ), erythromycin (ERY) and tylosin (TYL A, B, C and D) were extracted from soil using pressurized liquid extraction (PLE). Citric acid (pH 4.7) and methanol was used as extraction buffer, followed by tandem-solid-phase extraction (SPE) clean-up (SAX + HLB) for all compounds. For quantification two slightly different methods were employed using LC-MS-MS with MRM detection. The soil extraction method was validated using a loamy sand soil and a sandy soil, representing two typical Danish agricultural soils. Recoveries were 50-80% for the tetracyclines (CTC and OTC) and sulfadiazine (SDZ) and 60-100% for the macrolides (TYL and ERY). Limits of detection for the soil extraction method (LOD(soil)) were 0.6-5.6 microg kg(-1) soil for CTC and OTC, 0.9-2.9 microg kg(-1) soil for SDZ and 2.4-5.5 microg kg(-1) soil for TYL A and ERY. Furthermore, the method was applied to field samples taken from two agricultural fields fertilised with liquid manure containing CTC and TYL A. These results showed a decline in the content of antibacterial agents throughout the sampling period of 155 days from 10 to 15 microg CTC kg(-1) soil and 20-55 microg TYL A kg(-1) soil to below or near the LOD(soil) listed above. Finally, the method was applied to barley grains harvested from the fields. None of the antibacterial agents were measured in grain samples, but recoveries for spiked grain samples were similar to soil recoveries.  相似文献   

11.
环硫氯丙烷的均聚物或环硫氯丙烷与环氧氯丙烷的共聚物,在少量二乙烯三胺存在下制得预交联聚合物,将后者与硫氰化钾反应,制得两种侧链带有硫氰酸根的新型螯合树脂。它们对贵金属具有优良的吸附性能和高的吸附选择性。通过X射线光电予能谱初步探讨了树脂对金属离子的螯合作用  相似文献   

12.
Absorption spectrums of C60 fullerene in 10 various organic solvents in the range of 300–620 nm was studied. In all the solvents the C60 fullerene has four absorption maxima in the range under study. When an aromatic solvent has an ionization potential of 8.1 eV or lower a new additional absorption band appears in the absorption spectrum of C60 fullerene, caused by the formation of a charge-transfer complex (CTC) of the solvent and C60 fullerene.  相似文献   

13.
IntroductionReactivityratioscanofferthemessageofrelativereactivityofcomonomers.TWomonomerreactivityratioscanbeacquiredfromtheend-groupmodelproposedbyMayoandLewis,howevef,thereareonlyapparentreactivityratiosavailablefromthiskineticmodelwhencharge-transfercomplex(CTC)participatesinthecopolymerization.Therefore,thecopolymeriZationinwhichCTCexistsisworthyoffurtherresearch.Sofar,therearethreekineticmodelsofcopolymerizationwiththeparticipationofCTCinall,namely,SeinerandLittmodel',Shirotamodel…  相似文献   

14.
The goal of this research was to investigate the formation and reactivity of charge-transfer complexes (CTCs) among a homologous series of chlorophenols on TiO2. We previously showed that 2,4,5-trichlorophenol (245TCP) forms a CTC with Degussa P25, a commercial preparation of TiO2. Here, we probe how light energy influences reactivity and product formation. Slurries of P25 containing 245TCP were irradiated at 360, 400, 430, 480, and 550 nm. At each wavelength, the amount of transformation of 245TCP correlates to the diffuse-reflectance absorbance of a 245TCP/P25 system, supporting the CTC as the cause of reaction. In addition, polymeric products are formed only under wavelengths that excite the CTC, indicating a different reaction mechanism for the CTC than for bandgap excitation of TiO2. We also found a higher quantum efficiency for CTC reactivity than for bandgap activation of the catalyst, suggesting that the photocatalytic efficiency and selectivity can be improved for certain compounds by designing catalytic materials that form CTCs with them. Furthermore, to determine how chlorine substitution patterns affected adsorption and sub-bandgap reactivity, P25 slurries containing phenol, 4-chlorophenol, 2,4-dichlorophenol, or 2,4,6-trichlorophenol were probed following dark contact or irradiation at 360, 430, or 550 nm. With respect to the extent of adsorption, complexation, reaction, and polymerization on P25, the behavior of 245TCP far exceeded that of the other chlorophenols. Among these chlorophenols, only 2,4-dichlorophenol produced a polymeric product. 245TCP is unique among this family of chlorophenols, which we attribute to a chlorine arrangement that leads to a favorable orbital overlap with TiO2 and sterically permits coupling reactions. Our results demonstrate the critical role that charge-transfer complexation can play in determining the rates and products of photocatalytic reactions.  相似文献   

15.
The C‐terminal domain of lung surfactant protein C (CTC) precursor (proSP‐C) is involved in folding of the transmembrane segment of proSP‐C. CTC includes a Brichos domain with homologs in cancer‐ and dementia‐associated proteins. Mutations in the Brichos domain cause misfolding of proSP‐C and hence amyloid fibril formation in interstitial lung disease. Electrospray ionization mass spectrometry (ESI‐MS) with collision‐induced dissociation (CID) experiments was applied to study non‐covalent interactions between human recombinant CTC or its Brichos domain, and SP‐C analogs, homotripeptides and peptides designed to model amyloid fibril formation. The results show that the Brichos domain contains the peptide‐binding function of CTC. In titration experiments, apparent dissociation constants (KD) were in the micromolar range where triple‐valine showed the lowest KD and triple‐tyrosine the highest. Non‐hydrophobic peptides failed to form complexes with Brichos. CID revealed that complexes with aromatic peptide ligands are more stable in the gas phase than complexes with non‐aromatic ligands. The Brichos domain was also shown to bind fibril‐forming peptides containing aromatic/hydrophobic residues. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

16.
The apparent second-order rate constants for the reaction of methacryloyl chloride with methanol regularly increase on raising the acyl chloride-to-alcohol ratio. The variation of the rate constants is described by the Michaelis-Menten equation, indicating that the process involves initial formation of an associate with a probable structure of charge-transfer complex (CTC). Thermodynamic parameters of the CTC formation and rate constants and activation parameters for the transformation of CTC into the products have been determined.  相似文献   

17.
Intermolecular donor-acceptor charge transfer complex (CTC) formed in the electronic ground state between poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and 2,4,7-trinitrofluorenone (TNF) has been investigated by Raman and optical absorption spectroscopies. Blending of MEH-PPV and TNF results in appearance of the CTC absorption band in the optical gap of the both components and in changes in the characteristic MEH-PPV Raman bands including shifts, change in bandwidth, and intensity. The experimental data are similar in films and solutions indicating the CTC formation in both. We associate the low-frequency shift of the strongest MEH-PPV Raman band at approximately 1580 cm(-1) reaching 5 cm(-1) with partial electron transfer from MEH-PPV to TNF amounting approximately 0.2e(-). We suggest that polymer conjugated segments can form the CTC of variable composition MEH-PPV:TNF=1:X, where X相似文献   

18.
采用电化学石英晶体微天平(EQCM)技术, 研究了B-R缓冲溶液中邻联甲苯胺(o-TD)电氧化生成的电荷转移配合物(CTC)的电沉积及共存硫酸软骨素(CS)的影响. 在弱酸性和中性(pH=4.07-6.50)溶液中进行循环伏安扫描时, 观察到谐振频率的“V”字型响应, 表明o-TD电氧化会产生水溶性差的电荷转移配合物中间体, 该CTC可在金电极上沉积和溶出. 考察了溶液pH值、电位扫描速率及支持电解质的影响, 发现该“V”字型频率响应深度(-⊿f0V)与支持电解质有关, -⊿f0V大小顺序为0.20 mol·L-1 NaNO3>0.20 mol·L-1 NaClO4>0.10 mol·L-1 Na2SO4. 发现共存硫酸软骨素可显著增大-⊿f0V, 采用红外和紫外-可见光谱表征了CTC和CS间的相互作用, 并用EQCM法定量测算了CTC与CS间的摩尔结合比(x)及其电极收集效率(η). 结果表明, -⊿f0V响应随CS 浓度增加而增大, 在0.75-15.2 μmol·L-1 CS 范围内呈良好线性关系, 检测下限为50 nmol·L-1, 藉此建立了CS的电化学分析新方法, 具有电极表面可动态更新的特点.  相似文献   

19.
The influence of the polarity of the medium (B, ) on the thermodynamic characteristics of the formation of a charge transfer complex (CTC) and one electron transfer from a donor D to and acceptor A was studied in N-alkyl-substituted aniline (D) — tetracyanoethylene (A) systems. It was shown that in systems with CTC in which [B]/[D] 1, the limiting step in the reaction with one electron transfer in weakly polar solvents (<20) is the formation of molecular (AD), and in strongly polar sovents (>20), of ionic (AD) CTC. A correlation was established between the spectral (VCT) characteristics of the formation of the CTC and the kinetic parameters (keff) of one electron transfer reaction and degrees of charge transfer in molecular and ionic CTC were determined.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 167–173, March–April, 1989.  相似文献   

20.
The complexation of electron donor–acceptor complexes of 8-hydroxyquinoline (8HQ) and metadinitrobenzene (MNB) have been studied spectrophotometrically and thermodynamically in different polar solvent at room temperature. A new absorption band due to charge transfer (CT) transition is observed in the visible region. A new theoretical model has been developed which take into account the interaction between electronic subsystem of 8HQ and MNB. The results indicate the extent of charge transfer complexes (CTCs) formation to be more in less polar solvents. Stoichiometry of the complex was found to be 1:1 by straight line method and 1H NMR between donor and acceptor at the maximum absorption bands. Ionization potential (ID) and resonance energy (RN) were determined from the CT transition energy in different solvents. The formation constants of the complexes were determined in different polar solvents from which ΔG° formation of the complexes was estimated and also extinction coefficient of the charge transfer complex (CTC) was calculated. Oscillator strength, transition dipole strengths and maximum wavelength of the CTC (λCT) in various solvents and IR spectra of the CTC have also been discussed. It has been observed that all parameters described above changed with change in polarity and concentration of donor.  相似文献   

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