6674-22-2Relevant articles and documents
Photoinduced redox initiation for fast polymerization of acrylaytes based on latent superbase and peroxides
He, Minghui,Huang, Xun,Huang, Yugang,Zeng, Zhaohua,Yang, Jianwen
, p. 3172 - 3177 (2012)
The article presents a highly effective strategy for photopolymerization of acrylates via photolatent redox-accelerated reaction based on the synergistic photoinitiating systems containing photolatent superbase and readily available peroxides. Polymerization of acrylates could be instantly initiated with the effective interaction between the photogenerated amine and peroxides. Due to the persistent interaction of produced longeval amine with peroxides, remarkable post conversion after irradiation, which is significant for radiation crosslinking of photo-screened materials, was thus initially achieved in photoinitiated free radical polymerization. To explore the synergistic interactions of the photoinitiating systems, the effect of peroxide structures and QA-DBU:BPO ratios had been examined by RTIR, showing that all peroxides are applicable as the final conversion rate of acrylates is concerned. Further, BPO and CHP significantly accelerated the photopolymerization rate in air atmosphere. The synergistic efficiency of QA-DBU and BPO as a photopolymerization initiatiation system was close to that of the conventional D-1173 photoinitiator.
A thioxanthone-based photocaged superbase for highly effective free radical photopolymerization
He, Ming-Hui,Xu, Rui-Xin,Chen, Guang-Xue,Zeng, Zhao-Hua,Yang, Jian-Wen
, p. 1445 - 1448 (2014)
Thioxanthone-based N-phthalimidoamino acid ammonium salt (thioxanthen-DBU) as a photocaged base was synthesized and characterized. The photochemical properties and initiation mechanism were analyzed. It was found that the compound absorbs over the UV and visible region with relatively high absorption coefficients. Furthermore, the covalent binding of N-phthalimidoamino acid and type II chromophores (thioxanthone, TX) remarkably improved the photoreactivity. Specifically, in combination with a benzoyl peroxide initiator, thioxanthen-DBU was able to initiate the amine-mediated redox photopolymerization of trimethylol propane triacrylate (TMPTA), and an excellent photopolymerization profile was obtained.
Basicities and Nucleophilicities of Pyrrolidines and Imidazolidinones Used as Organocatalysts
An, Feng,Maji, Biplab,Min, Elizabeth,Ofial, Armin R.,Mayr, Herbert
supporting information, p. 1526 - 1547 (2020/02/04)
The Br?nsted basicities pKaH (i.e., pKa of the conjugate acids) of 32 pyrrolidines and imidazolidinones, commonly used in organocatalytic reactions, have been determined photometrically in acetonitrile solution using CH acids as indicators. Most investigated pyrrolidines have basicities in the range 16 aH aH aH 12.6) and the 2-imidazoliummethyl-substituted pyrrolidine A21 (pKaH 11.1) are outside the typical range for pyrrolidines with basicities comparable to those of imidazolidinones. Kinetics of the reactions of these 32 organocatalysts with benzhydrylium ions (Ar2CH+) and structurally related quinone methides, common reference electrophiles for quantifying nucleophilic reactivities, have been measured photometrically. Most reactions followed second-order kinetics, first order in amine and first order in electrophile. More complex kinetics were observed for the reactions of imidazolidinones and several pyrrolidines carrying bulky 2-substituents, due to reversibility of the initial attack of the amines at the electrophiles followed by rate-determining deprotonation of the intermediate ammonium ions. In the presence of 2,4,6-collidine or 2,6-di-tert-butyl-4-methyl-pyridine, the deprotonation of the initial adducts became faster, which allowed the rate of the attack of the amines at the electrophiles to be determined. The resulting second-order rate constants k2 followed the correlation log?k2(20 °C) = sN(N + E), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the two solvent-dependent parameters N and sN. In this way, the organocatalysts A1-A32 were integrated in our comprehensive nucleophilicity scale, which compares n-, -, and σ-nucleophiles. The nucleophilic reactivities of the title compounds correlate only poorly with their Br?nsted basicities.
Photoinduced Proton-Transfer Polymerization: A Practical Synthetic Tool for Soft Lithography Applications
Khan, Anzar,Yeo, Hyunki
, p. 3479 - 3488 (2020/02/27)
Proton-transfer photopolymerization through the thiol-epoxy click reaction is shown to be a versatile new method for the fabrication of micro- A nd nanosized polymeric patterns. In this approach, complexation of a guanidine base, diazabicycloundecene (DBU), with benzoylphenylpropionic acid (ketoprofen) generates a photolabile salt. Under illumination at a wavelength of 365 nm, the salt undergoes a photodecarboxylation reaction to release DBU as a base. The base-catalyzed ring opening reaction then creates cross-linked poly(β-hydroxyl thio-ether) patterns. The surface chemistry of these patterns can be altered through alkylation of the thio-ether linkages. For example, a reaction with bromoacetic acid produces a hitherto unknown sulfonium/carboxylate-based zwitterionic motif that endows antibiofouling capacity to the micropatterns.
A 1, 8 - diazabicyclo synthetic method (by machine translation)
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Paragraph 0014-0017, (2019/06/27)
The present invention provides a 1, 8 - diazabicyclo synthetic method, the technical scheme of the DBU synthetic route to an innovative design. Specific perspective, the invention first of all the use of ε-caprolactam, acrylonitrile and hydroquinone reaction generating N - (β - cyanoethyl) - ε-caprolactam, on this basis, will it and to toluene sulfonic acid in catalytic reaction under the condition, and then carry on ice bath, and then under the protection of nitrogen with benzyl chloride reaction, the resulting product to EDTA as the catalyst with high sodium borate reaction, the product of the reaction 3 - phenylpropanoic acid mixed with 4 - nitro benzyl chloride reaction to obtain the product. For the reaction product, filtered and the filtrate is extracted with ethyl acetate, the combined solid-liquid separation after solid phase, then the solid phase for reducing the drying to obtain the final product. The invention adopts the brand new synthetic route, its mild reaction conditions, material cost is relatively low, promotion prospect. (by machine translation)
MANUFACTURING METHOD OF DIAZABICYCLO COMPOUND
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Paragraph 0018; 0042; 0044; 0048, (2018/06/08)
PROBLEM TO BE SOLVED: To provide a manufacturing method for providing a diazabicyclo compound from hydrochloric acid having a diazabicyclo group, which is suitable for industrial production. SOLUTION: There is provided a method for manufacturing a diazabicyclo compound by neutralization with using 20 wt.% to 50 wt.% of an alkali metal hydroxide solution or 10 wt.% to 50 wt.% of an alcohol solution of alkali metal alkoxide of 2.0 times molar equivalent to 3.5 times molar equivalent to hydrochloric acid having a diazabicyclo group. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPO&INPIT
Base-induced reversible H2 addition to a single Sn(ii) centre
Turnell-Ritson, Roland C.,Sapsford, Joshua S.,Cooper, Robert T.,Lee, Stella S.,F?ldes, Tamás,Hunt, Patricia A.,Pápai, Imre,Ashley, Andrew E.
, p. 8716 - 8722 (2018/12/10)
A range of amines catalyse the oxidative addition (OA) of H2 to [(Me3Si)2CH]2Sn (1), forming [(Me3Si)2CH]2SnH2 (2). Experimental and computational studies point to 'frustrated Lewis pair' mechanisms in which 1 acts as a Lewis acid and involve unusual late transition states; this is supported by the observation of a kinetic isotope effect for Et3N. When DBU is used the energetics of H2 activation are altered, allowing an equilibrium between 1, 2 and adduct [1·DBU] to be established, thus demonstrating reversible oxidative addition/reductive elimination (RE) of H2 at a single main group centre.
A rechargeable hydrogen battery based on Ru catalysis
Hsu, Shih-Fan,Rommel, Susanne,Eversfield, Philipp,Muller, Keven,Klemm, Elias,Thiel, Werner R.,Plietker, Bernd
supporting information, p. 7074 - 7078 (2014/07/08)
Apart from energy generation, the storage and liberation of energy are among the major problems in establishing a sustainable energy supply chain. Herein we report the development of a rechargeable H2 battery which is based on the principle of the Ru-catalyzed hydrogenation of CO2 to formic acid (charging process) and the Ru-catalyzed decomposition of formic acid to CO2 and H2 (discharging process). Both processes are driven by the same catalyst at elevated temperature either under pressure (charging process) or pressure-free conditions (discharging process). Up to five charging-discharging cycles were performed without decrease of storage capacity. The resulting CO2/H2 mixture is free of CO and can be employed directly in fuel-cell technology. Simple but efficient: A readily accessible Ru catalyst is the basis for a reversible H 2/CO2-driven battery. At elevated temperatures both the reduction of CO2 to formic acid and the decomposition of formic acid were realized with 0.075 mol % of the Ru complex. Several charging and discharging cycles were performed with comparable storage-release efficiency. Furthermore, the partial removal of defined gas amounts is possible under pressure.
Application to photoreactive materials of photochemical generation of superbases with high efficiency based on photodecarboxylation reactions
Arimitsu, Koji,Endo, Ryosuke
, p. 4461 - 4463 (2014/01/06)
A thin film of polystyrene containing 4c was spin-coated on a CaF2 plate and irradiated with 365 nm light. The absorption band arising from the carboxylate of 4c at 1372 cm-1 in the FTIR spectrum decreased after UV irradiation. Radical UV curing materials that are well established in the marketplace have drawbacks because of high volume shrinkage and oxygen inhibition. The anionically cured film showed high transparency and no volume shrinkage, in contrast to a conventional radical UV curing system, which showed large volume shrinkage. This is probably due to relatively low quantum yields for photobase generation and weaker basicity of photo-generated bases, leading to low photosensitivity of photoreactive materials sensitized with photobase generators. Furthermore, many of the photobase generators reported are generally prepared via several synthetic steps.
Enhancing the anion affinity of urea-based receptors with a Ru(terpy) 22+ chromophore
Baggi, Giorgio,Boiocchi, Massimo,Ciarrocchi, Carlo,Fabbrizzi, Luigi
, p. 5273 - 5283 (2013/06/26)
Covalent linking of a Ru(terpy)22+ substituent improves recognition and sensing properties of the urea subunit toward anions. Urea's anion affinity is enhanced by the electrostatic attraction exerted by the RuII cation and by the electron-withdrawing effect exerted by the entire polypyridine-metal complex. Such an enhancement of the anion affinity, which results from the combination of a through-space and a through-bond effect, is greater than that exerted by the classical neutral electron-withdrawing substituent nitrophenyl. Small yet significant modifications of π-π* and MLCT bands of the Ru(terpy)22+ chromophore, detected through UV-vis spectrophotometric titrations, allowed the determination of the constants for the formation of receptor-anion H-bond complexes in diluted MeCN solution. On 1H NMR titration experiments, carried out under more concentrated conditions, the interaction of a second Cl- ion was observed, taking place through an outer-sphere mechanism. The Ru(terpy) 22+ substituent favors the deprotonation of a urea N-H fragment on addition of a second equivalent of fluoride, with formation of HF2-.
