The synthesis,absorption and fluorescence of polar diketo-pyrrolo-pyrroles

The effect of electron-donor (piperidino) and electron-acceptor (cyano) groups on the absorption maxima of some diketo-pyrrolo-pyrroles in DMSO solution was investigated both experimentally and theoretically. The syntheses of push–pull substituted 3-(4-piperidinophenyl)-6-(4-cyanophenyl)-2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-dione are reported for the first time; 3,6-diphenyl-2,5-dihydropyrrolo[3,4-c]pyrrol-1,4-diones substituted with either one or two piperidino or cyano groups in the para-positions of the phenyl rings were also synthesized. Whilst both types of substituent produce a bathochromic and hyperchromic shifts with respect to the parent unsubstituted compound, the influence of the piperidino group is strongest. Symmetrically substituted derivatives show well-resolved vibronic structures, while the spectra of polar, unsymmetrical compounds were poorly resolved because of strong dipole–dipole interaction with the polar solvent. The fluorescence of all compounds was intense and a significant increase in the Stokes shift of polar derivatives was another consequence of dipole–dipole interactions with the solvent in the excited state.     

聚酰胺-胺型树枝状分子的合成及其荧光性质

以丙烯酸甲酯和乙二胺为原料通过Michael加成和酯氨解重复反应合成了以乙二胺为核的0.5～4.0G的半代和整代聚酰胺-胺树枝状分子。并用红外、紫外、荧光等对合成产物进行了表征。     

Synthesis, photophysical and electrochemical properties of 1-aminoperylene bisimides

1-Aminoperylene bisimides (1a-1c) were synthesized under mild condition in high yields, and were characterized by FT-IR, ¹H NMR, UV-Vis, HRMS spectra, cyclic voltammetry, differential scanning calorimetry, and thermogravimetric analyses. These compounds are stable up to 310 °C according to thermogravimetric analyses. They undergo two quasi-reversible one-electron oxidations and two quasi-reversible one-electron reductions in dichloromethane at modest potentials. Their spectroscopic properties in various conditions and complementary density functional theory (DFT) calculations are reported.     

Shaping the absorption and fluorescence bands of a class of efficient,photoactive chromophores: synthesis and properties of some new 3H-xanthen-3-

An approach to the systematic design of absorption and fluorescence band shapes is developed from considerations of the solvatochromism and electronic perturbation of unsymmetrical chromophores. The predicted spectral shifting and line broadening has been demonstrated within a series of newly synthesized substituted 6-amino-3H-xanlhen-3-ones 1. A new method of presenting bandwidth data is developed which utilizes dipole strength-weighted moments of absorption bands.     

The synthesis and two-photon excited fluorescence properties of novel branched fluorene derivatives

Two novel, V-shaped fluorene derivatives branched from triphenylamine and their linear analogue were synthesized via Cu-mediated Ullmann condensation and subsequent Pd-catalyzed Heck coupling reaction. Their two-photon excited fluorescence properties as well as their linear absorption and single-photon excited fluorescence properties were examined. When excited at 730 nm by a Ti:sapphire femtosecond laser, the compounds exhibited strong two-photon excited blue fluorescence. The two-photon excited fluorescence cross-sections of V-shaped derivatives in toluene at 730 nm were ∼506 GM in the case of N, N-bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-aniline) and 397 GM for N, N-Bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-4-acetyl-aniline), respectively.     

The synthesis and two-photon excited fluorescence properties of novel branched fluorene derivatives

Two novel, V-shaped fluorene derivatives branched from triphenylamine and their linear analogue were synthesized via Cu-mediated Ullmann condensation and subsequent Pd-catalyzed Heck coupling reaction. Their two-photon excited fluorescence properties as well as their linear absorption and single-photon excited fluorescence properties were examined. When excited at 730 nm by a Ti:sapphire femtosecond laser, the compounds exhibited strong two-photon excited blue fluorescence. The two-photon excited fluorescence cross-sections of V-shaped derivatives in toluene at 730 nm were 506 GM in the case of N, N-bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-aniline) and 397 GM for N, N-Bis{7-[4′-(N, N-diphenylamino)styryl]-9,9-diethyl-9H-fluorene-2-yl}-4-acetyl-aniline), respectively.     

The synthesis,two-photon absorption and blue upconversion fluorescence of novel,nitrogen-containing heterocyclic chromophores

Novel, nitrogen-containing heterocyclic chromophores based on either 1,2,4-triazine or an imidazole core were synthesized using a three-component, one-pot reaction under microwave irradiation. Structures were verified by ¹H NMR, IR, MS and elemental analyses while crystal structure was determined using X-ray diffraction. The two-photon absorption and two-photon upconverted blue fluorescent emission characteristics were investigated experimentally; preliminary structure–photophysical property relationships were established. Chromophores that contained the imidazole moiety displayed more potent two-photon absorption than compounds based upon 1,2,4-triazine and also exhibited a strong two-photon upconverted blue fluorescent emission peak at around 443–476 nm. Significant enhancement of the two-photon absorption cross-section was achieved by fusing a benzoxazole moiety onto the phenanthro[9,10-d]imidazole ring.     

The synthesis,photophysical properties and two-photon absorption of triphenylamine multipolar chromophores

Triphenylamine core multipolar derivatives were synthesized via the Wittig reaction and Heck reaction and were characterized by MS, NMR, IR; melting points and decomposition temperatures were determined using differential scanning calorimetry. The photophysical as well as the linear and nonlinear spectral properties of multipolar compounds with a triphenylamine core were compared to those of corresponding dipolar compounds. The multipolar chromophores displayed large two-photon absorption and strong optical power limiting properties. An extended π-conjugated system and increased intramolecular cooperative effect are responsible for the observed, large two-photon absorption character.     

The synthesis of asymmetrically substituted amphiphilic phthalocyanines and their gas-sensing properties

A series of asymmetrically substituted amphiphilic phthalocyanines have been synthesized. They have been deposited as Langmuir–Blodgett films onto glass and/or glass substrates bearing aluminum interdigitated electrode patterns. The films show fast response to NO₂ with almost complete recovery at room temperature. It is indicated that layer ordering and molecular packing within the LB films are important factors determined the gas-sensing properties.     

多元致孔剂合成吸附树脂及吸附性能研究

以苯乙烯为单体,二乙烯苯为交联剂,甲苯和聚乙二醇为混合致孔剂,采用悬浮聚合的方法合成吸附树脂,研究树脂对苯酚的静态吸附。结果表明,当交联度50%,致孔剂:单体=1.5,甲苯:聚乙二醇400=1:1时,树脂对苯酚的吸附容量最大,达到85.16 mg/g,最佳吸附平衡时间为2 h;对树脂吸附容量影响最大的是致孔剂与单体的配比,其次依次是混合致孔剂中单体的配比和交联度。     

In-situ synthesis of silica aerogel in polyethylene terephthalate fibre nonwovens and their composite properties on acoustical absorption behavior

In this research work we focus on engineering the silica aerogel/polyethylene terephthalate (PET) fibre nonwoven fabric composites with various silica content during in-situ synthesis of silica aerogels in the nonwovens and their composite properties on sound absorption. The silica content was varied by varying the molar ratio of methanol (MeOH)/tetraethyl orthosilicate (TEOS) from 110 to 28. The gelation of silica alcogel took place inside the fabric followed by silylation and atmospheric pressure drying. The aerogel/PET nonwoven composites were characterized by FTIR, TGA and contact angle to explain the aerogel content and its behavior. Moreover, the physical properties such as thickness, bulk density, specific airflow resistance, and mean flow pore size have been investigated. The two microphone transfer function method was used to test the sound absorption coefficient (SAC) of aerogel composites at 1/3rd octave frequencies of 50–6300 Hz. The aerogel/PET nonwoven composites have exhibited higher SAC than the untreated or control PET nonwoven for the entire frequency range. The suitable solvent molar ratio of 55 has been recommended for synthesis of silica aerogels by considering not only the silica content to have high sound absorption but also based on hydrophobic characteristics of aerogel/PET nonwoven composites.     

Lipase-catalyzed synthesis of hydroxy stearates and their properties

Hydroxy fatty acid (HFA) esters of long-chain alcohols, such as hydroxy stearates, have potential applications from lubricants to cosmetics. These esters were synthesized enzymatically to overcome the problems associated with chemical processes. An immobilized lipase, Rhizomucor miehei, was employed as catalyst in the esterification reaction between hydroxy-stearic acid as a source of HFA and monohydric fatty alcohols (C₈–C₁₈). The yields of esters were in the range of 82–90% by conducting the reactions at 65±2°C, 2–5 mm Hg pressure, and 10% lipase concentration. The products were analyzed by infrared spectroscopy, and some of their analytical characteristics were determined.     

碳包覆空心Fe_3O_4纳米球的制备及其电磁波吸收特性研究

以六水合氯化铁为铁源,尿素为沉淀剂和软模板,乙二醇为溶剂,通过溶剂热法制备分散性良好且尺寸均匀的空心Fe_3O_4纳米颗粒,采用二次水热法制备核-壳结构的空心Fe_3O_4/C纳米颗粒。研究表明,空心状的Fe_3O_4纳米颗粒表面均匀地包覆了一层无定型碳层。相比单独的空心Fe_3O_4纳米颗粒,包碳后核壳结构的Fe_3O_4/C复合材料电磁波吸收性能显著增强。在匹配厚度仅为4.5 mm时,在11.6 GHz时,其最小反射损耗值可达到-25.2 d B,表现出良好的微波吸波特性。此类核-壳状Fe_3O_4/C磁性球在雷达波吸收、通讯领域等具有广泛的应用前景。     

碳包覆空心Fe_3O_4纳米球的制备及其电磁波吸收特性研究

以六水合氯化铁为铁源,尿素为沉淀剂和软模板,乙二醇为溶剂,通过溶剂热法制备分散性良好且尺寸均匀的空心Fe_3O_4纳米颗粒,采用二次水热法制备核-壳结构的空心Fe_3O_4/C纳米颗粒。研究表明,空心状的Fe_3O_4纳米颗粒表面均匀地包覆了一层无定型碳层。相比单独的空心Fe_3O_4纳米颗粒,包碳后核壳结构的Fe_3O_4/C复合材料电磁波吸收性能显著增强。在匹配厚度仅为4.5 mm时,在11.6 GHz时,其最小反射损耗值可达到-25.2 d B,表现出良好的微波吸波特性。此类核-壳状Fe_3O_4/C磁性球在雷达波吸收、通讯领域等具有广泛的应用前景。     

含氰基离子液体的物理性能及其对SO_2的吸收性能

对两种阴离子含氰基的离子液体1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])的密度、粘度及热稳定性等物理性质进行了研究,探讨了离子液体的分子体积V_m、标准熵S~0、晶格能U_(POT)等热力学性能。同时对两种离子液体的脱硫性能进行了研究。结果表明,两种离子液体的热稳定性较高,能够适用于烟气脱硫应用。两种离子液体均表现出良好的脱硫性能,20℃条件下,1 mol[Bmim][SCN]可吸收3.04 mol SO_2,且[Emim][SCN]、[Bmim][SCN]循环脱硫5次脱硫性不变。通过核磁共振H谱和红外光谱对两种离子液体的脱硫机理进行研究,发现离子液体和SO_2的结合主要为物理作用。     

含氰基离子液体的物理性能及其对SO_2的吸收性能

对两种阴离子含氰基的离子液体1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])的密度、粘度及热稳定性等物理性质进行了研究,探讨了离子液体的分子体积V_m、标准熵S⁰、晶格能U_(POT)等热力学性能。同时对两种离子液体的脱硫性能进行了研究。结果表明,两种离子液体的热稳定性较高,能够适用于烟气脱硫应用。两种离子液体均表现出良好的脱硫性能,20℃条件下,1 mol[Bmim][SCN]可吸收3.04 mol SO_2,且[Emim][SCN]、[Bmim][SCN]循环脱硫5次脱硫性不变。通过核磁共振H谱和红外光谱对两种离子液体的脱硫机理进行研究,发现离子液体和SO_2的结合主要为物理作用。     

Facile synthesis of amino-functionalized polyphosphazene microspheres and their application for highly sensitive fluorescence detection of Fe3+

Amino-functionalized highly crosslinked organic–inorganic hybrid polyphosphazene microspheres were prepared via a one-pot polycondensation method and served as a fluorescent sensor for the detection of Fe³⁺ in solution. With the introduction of p-phenylenediamine unites, the polyphosphazene microspheres could be endowed with fluorescent property and abundant active amino groups on the surface. The microspheres were further used as the fluorescent sensor for the detection of Fe³⁺. Fluorescence study showed high sensing sensitivity and selectivity of the microspheres, and the limit of detection was determined as 0.076 μM for Fe³⁺. Active amino groups on the surface could efficiently improve the detection sensitivity of Fe³⁺. Moreover, highly crosslinked organic–inorganic hybrid structure was beneficial to the photostability and thermostability, enabled the microspheres to be possible for constructing practicable sensors. This work is expected to inspire the design of advanced polyphosphazene-based fluorescent sensors for applications in analytical detection. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48937.     

Lipase-catalyzed synthesis and properties of estolides and their esters

Eight lipases were screened for their ability to synthesize estolides from a mixture that contained lesquerolic (14-hydroxy-11-eicosenoic) acid and octadecenoic acid. With the exception ofAspergillus niger lipase, all 1,3-specific enzymes (fromRhizopus arrhizus andRhizomucor miehei lipases) were unable to synthesize estolides.Candida rugosa andGeotrichum lipases catalyzed estolide formation at >40% yield, with >80% of the estolide formed being monoestolide from one lesquerolic and one octadecenoic acyl group:Pseudomonas sp. lipase synthesized estolides at 62% yield, but the product mixture contained significant amounts of monoestolide with two lesquerolic acyl groups as well as diestolide. ImmobilizedR. miehei lipase was chosen to catalyze the esterification of mono-and polyestolide, derived synthetically from oleic acid, with fatty alcohols or α,ω-diols. Yields were >95% for fatty alcohol reactions and >60% for diol reactions. In addition, the estolide linkage remained intact through the course of the esterification process. Esterification of estolides improved the estolide’s properties—for example, lower viscosity and higher viscosity index—but slightly raised the melting point. Estolides and, particularly, estolide esters may be suitable as lubricants or lubricant additives.     

不同有机醇条件下溶剂热法制备Ga_2O_3及其光催化性能研究

以水(water)、异丙醇(IPA)、正戊醇(n-PTL)和正己醇(n-H)为溶剂,采用溶剂热法制备了Ga_2O_3(Ga_2O_(3water)、Ga_2O_(3IPA)、Ga_2O_(3n-PTL)和Ga_2O_(3n-H))。利用X射线衍射法(XRD)、扫描电镜(SEM)、紫外可见漫反射(UVVis DRS)、比表面积测定仪(BET)对催化剂晶相结构、形貌、比表面积以及其带隙进行了表征。表明,其中Ga_2-O_(3water)为α-Ga_2O_3,Ga_2O_(3IPA)、Ga_2O_(3n-PTL)和Ga_2O_(3n-H)都为β-Ga_2O_3,菱柱状形貌;Ga_2O_(3water)、Ga_2O_(3IPA)、Ga_2O_(3n-PTL)和Ga_2O_(3n-H)的比表面积分别为8.564,12.77,10.75,9.776 m~2/g,其中Ga_2O_(3IPA)的比表面积最大。在紫外光(λ387nm)照射下,以罗丹明B(Rhodamine B,RhB)为目标污染物在相同条件下,比较光催化降解RhB特性发现,Ga_2O_(3IPA)活性最好,反应4h,RhB基本降解完全。通过测定RhB降解过程中红外吸收光谱及TOC的变化,Ga_2O_(3IPA)对RhB深度氧化矿化效率高。运用ESR技术跟踪测定光催化降解过程中氧化物种的变化及捕获实验,表明Ga_2O_(3IPA)的光催化降解过程涉及空穴、羟基自由基(·OH)和超氧自由基(O_2~(·-))的氧化历程。     

乙酸丁酯合成工艺的热安全性研究

为了探究正丁醇在浓硫酸的催化作用下与乙酸酐反应合成乙酸丁酯工艺的热危险性,采用差示扫描量热仪研究了正丁醇、乙酸酐和乙酸丁酯的热分解情况,并采用反应量热仪分别探究工艺温度、乙酸酐滴加速率和搅拌速率对合成反应放热的影响。结果表明,正丁醇、乙酸酐和乙酸丁酯升温扫描阶段均表现为吸热过程,起始温度依次为117.9,139.4,127.2℃。在工艺优化过程中,增加加料时间、升高工艺温度或增加搅拌速率,均能够降低反应在热失控条件下达到的最大温度和最大热累计度,增加反应的安全性以及提高反应热转化率。