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Effect of solvent polarity on Excited-State Double Proton Transfer Process of 1,5-Dihydroxyanthraquinone

Chinese Journal of Chemical Physics 2022年第2期35卷 289-294,I0002页

作者： Zheng-Ran Wang Li-Xia Zhu Xing-Lei Zhang Bo Li Yu-Liang Liu Yong-Feng Wan Qi Li Yu Wan Hang Yin Ying Shi Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China

The excited-state double proton transfer(ESDPT)properties of 1,5-dihydroxyanthraquinone(1,5-DHAQ)in various solvents were investigated using femtosecond transient absorption spectroscopy and the DFT/TDDFT *** steady-state fluorescence spectra in toluene,tetrahydrofuran(THF)and acetonitrile(ACN)solvents presented that the solvent polarity has an effect on the position of the ESDPT fluorescence emission peak for the 1,5-DHAQ *** absorption spectra show that the increasing polarity of the solvent accelerates the rate of excited state *** potential energy curves analysis further verified the experimental *** ESDPT barrier decreases gradually with the increase of solvent polarity from toluene,THF to ACN *** is convinced that the increase of solvent polarity can promote the occurrence of the ESDPT dynamic processes for the 1,5-DHAQ *** work clarifies the mechanism of the influence of solvent polarity on the ESDPT process of 1,5-DHAQ,which provides novel ideas for design and synthesis of new hydroxyanthraquinone derivatives.

关键词： Density functional theory Time-dependent density functional theory Femtosecond transient absorption spectrum solvent polarity Excited-state double proton transfer Hydroxyanthraquinone compound

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EFFECTS OF solvent polarity ON FREE RADICAL COPOLY MERIZATION OF 5-HEXENOIC ACID AND ACRYLONITRILE

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Chinese Journal of Polymer Science 1987年第2期5卷 141-148页

作者：王兵谢世杉曹孟骏 Chengdu Institute of Organic Chemistry Academia Sinica Chengdu Chengdu Institute of Organic Chemistry Academia Sinica Chengdu

The effects of solvent polarity on free radical copolymerization of 5-hexenoie acid and acrylonitrile at 60℃ were studied. It was observed thatas the polarity of solvents enhanced, both the copolymcrization rate and the reactivity ratios r1, r2 increased, while the alternating tendency of monomer units in copolymer chain decreased. It is believed that the solvent polarity raises the reactivities of acrylonitrile monomer and its growing chain radical, but causes no distinct variation in those of 5-hexenoic acid.

关键词： Copolymerization reactivities solvent polarity Poly (5-hexenoic acid-co-acrylonitrile) Mathematical analyse O-e scheme

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Effects of Hydrogen-bonding Interaction and polarity on Emission Spectrum of Naphthalene-Triethylamine in Mixed solvent

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Chemical Research in Chinese Universities 2004年第5期20卷 606-611页

作者： Yoshimi Sueishi Shunzo Yamamoto Graduate School of Natural Science and Technology Okayama University 3-1-1 Tsushima-Naka Okayama 700-8530 JapanGraduate School of Natural Science and Technology Okayama University 3-1-1 Tsushima-Naka Okayama 700-8530 Japan

The effects of the protic and aprotic polar solvents on the emission spectrum of the naphthalene-triethyl-amine system in THF were studied under conditions of steady-state illumination. The fluorescence spectrum of the naphthalene-triethylamine system consists of two emission bands, the fluorescence band of naphthalene(band A, 329 nm) and the emission band of the exciplex(band B, 468 nm). The intensities of both the emission bands decrease with increasing the solvent polarity. The intensity of band B also decreases due to the hydrogen-bonding interaction between triethylamine and protic solvent, while that of band A increases. It is thus suggested that the quenching of naphthalene fluorescence by triethylamine in THF occurs through the charge transfer and electron transfer reactions. The spectral changes upon the increase of solvent polarity can be explained by the dependences of the equilibrium constant between exciplex and ion-pair and the rate constant for the electron transfer reaction from triethylamine to the excited naphthalene on the relative permittivity of solvent. It is shown that the formation of intermolecular hydrogen-bonding between triethylamine and protic solvent suppresses the quenching reaction by the decrease in free amine. Acetonitrile has only a polar effect and trichloroacetic acid only a hydrogen-bonding(or protonation) effect, while alcohols have both the effects. The effects of alcohols could be separated into the effects of solvent polarity and intermolecular hydrogen-bonding interaction quantitatively.

关键词： Naphthalene-triethylamine Fluorescence spectrum solvent effect solvent polarity Hydrogen-bonding interaction.

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Advancements in Polymer Science: Synthesis, Characterization, and Biomedical Applications of Homopolymers and Copolymers

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Open Journal of Polymer Chemistry 2024年第3期14卷 167-198页

作者： Anaif M. Alhewaitey Ishrat Khan Emmanuel Ramsey Buabeng Department of Chemistry Clark Atlanta University Atlanta USA Department of Chemistry University of Tabuk Tabuk Saudi Arabia Department of Chemistry Georgia State University Atlanta GA USA

Polymer science encompasses a different range of materials critical to industries spanning from packaging to biomedicine. Understanding the synthesis, characterization, and applications of common homopolymers and copolymers is fundamental to advancing polymer research and development. In this comprehensive review, we explore various preparation methods, including free radical, anionic, and cationic polymerization, utilized for synthesizing homopolymers and copolymers. Furthermore, we investigate solvent choices commonly employed for polymer characterization, ranging from neat conditions, polar protic and polar aprotic solvents. We also explored characterization techniques, including Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Atomic Force Microscopy (AFM), Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). In addition to industrial applications, we highlight the diverse biological applications of homopolymers, poly(2-hydroxyethyl methacrylate) (pHEMA) and polystyrene, which find its extensive use in biomedicine. By synthesizing and analyzing this wealth of information, this review aims to provide a comprehensive understanding of the synthesis, characterization, and applications of homopolymers and copolymers, with a particular focus on their biological applications. This holistic approach not only contributes to advancements in polymer science and technology but also fosters innovation in biomedicine, ultimately benefiting human health and well-being.

关键词： Homopolymer Copolymer Poly(2-hydroxyethyl methacrylate) (pHEMA) Polystyrene Free Radical Polymerization Atomic Force Microscopy solvent polarity

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Probing the Impact of solvent on the Strength of Lewis Acids via Fluorescent Lewis Adducts

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Precision Chemistry 2023年第1期1卷 49-56页

作者： Amy E.Laturski Joshua R.Gaffen Paul Demay-Drouhard Christopher B.Caputo Thomas Baumgartner Department of Chemistry York UniversityTorontoON M3J 1P3Canada

Various methods have been developed to measure the strength of a Lewis acid.A major challenge for these measurements lies in the complexity that arises from variable solvent interactions and perturbations of Lewis acids as their reaction environment ***,we investigate the impact of solvent effects on Lewis acids for the first time as measured by the fluorescent Lewis adduct(FLA)*** binding of a Lewis acid in various solvents reveals a measurable dichotomy between both polarity and donor ability of the *** not strictly separable,we observe that the influence of solvent polarity on Lewis acid unit(LAU)values is distinctly opposite to the influence of donor *** dichotomy was confirmed by titration data,illustrating that solvation effects can be appropriately and precisely gauged by the FLA method.

关键词： Fluorescence Fluorescent Lewis adducts Lewis acids Effective Lewis acidity solvent polarity solvent donor strength

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The Enhancement of Band Edge Emission from ZnS/Zn（OH）2 Quantum Dots

The Enhancement of Band Edge Emission from ZnS/Zn（OH）2 Qua...

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第一届全国纳米技术与应用学术会议

作者： Hatim Mohamed El-Khair, Ling XU, Xinfan HUANG, Minghai LI and Kunji CHENNational Laboratory of Solid State Microstructures and Department of physicsNanjing University, Nanjing 210093, China

＜正＞ Wurtzite structure monodisperse ZnS quantum dots （QDs） of 1 to 5 nm diameters were synthesized by colloidal chemical method. The strong enhancement of the blue shifted band edge emission from Zn（OH）2 capped ZnS QDs has been observed which indicates the role of surface passivation and supports the quantum size effect. The mismatching of the solvent polarities for stabilizer and QDs precursors lead to detectable far red shifted emission from ZnS core QDs. This emission is attributed to the surface trap states of different energies.

关键词： ZnS QDs Surface passivation band-edge luminescence solvent polarity

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