Liang Li,Huijuan Cui,Zhou Yang,Xutang Tao,Xinsong Lin,Ning Ye,Huai Yang
The synthesis of a series of thienyl-substituted pyridinium salts with different counter-anions and their second-order nonlinear optical (NLO) properties are described. Kurtz powder tests revealed that, out of the twelve new pyridinium salts, four possess noncentrosymmetric structures and the maximum powder second harmonic generation (SHG) efficiency is 0.6 times of DAST. Single crystals of three new salts were successfully obtained from methanol by slow evaporation method. X-Ray studies exhibited that they crystallized in the monoclinic space groupP21/c, P21, and P21/n, respectively. (E)-4-(2-(5-(dimethylamino)thiophen-2-yl)vinyl)-1-methylpyridinium 4-hydroxybenzenesulfonate (3c) forms a hydrated noncentrosymmetric phase with a large macroscopic optical nonlinearity 0.5 times of that of DAST at the non-resonant wavelength of λ = 2109 nm, while both (E)-4-(2-(5-(dimethylamino)thiophen-2-yl)vinyl)-1-methylpyridinium 2-amino-3,5-dimethylbenzenesulfonate (3i) and (E)-4-(2-(5-(dimethylamino)thiophen-2-yl)vinyl)-1-methylpyridinium iodide (3a) crystallize in centrosymmetric structures.
Wang Weiqi,Wang Fan,Wang Yuqing,Zhang Lili,Okamoto Yoshio,Shen Jun
Four cellulose derivatives bearing benzothienyl or carbazolyl fluorophore pendants were successfully synthesized through carbamoylation followed by Steglich esterification or only esterification process, respectively. The enantioselective fluorescent sensing properties of the obtained derivatives were then evaluated using eight chiral substrates, including chiral aromatic amines and chiral amino alcohol-based drug intermediates. The four bulky host macromolecules exhibited good enantioselective fluorescence response to most of the tested guests with high enantioselectivity and sensitivity. Especially, a high enantiomeric fluorescence difference ratio ( ef = 37.16) was achieved on cellulose tris(2-benzothienylformate) ( Cel - 3 ) for the α-methylbenzylamine ( Q2 ), an important chiral agricultural drug intermediate. Worthy to be mentioned, an interesting opposite fluorescence response and a dual fluorescence enhancement pattern were also observed on the benzothienyl derivative Cel - 3 for the enantiomer pairs of 1-(4-methoxyphenyl) ethylamine ( Q3 ) and phenylglycinol ( Q6 ), a critical intermediate for chiral drug as an antilipemic agent in high demand, respectively. It indicated that the bulky Cel - 3 possessed excellent enantioselective fluorescent sensing properties to the chiral aromatic amine and amino alcohols, revealing good potential as efficient chiral fluorescent sensors. It was speculated that a beneficial chiral domain may be constructed by the appropriate arrangement of bulky conjugated benzothienyl or carbazolyl pendants on the phenylcarbamates or esters surrounding the helical backbone of cellulose, which was crucial for the efficient chiral fluorescent sensing performance. The introduction of bulky fluorophore pendants on the cellulose phenylcarbamates or esters presents an efficient strategy to produce effective chiral fluorescent recognition materials. Graphical Abstract
Fan Wang,Yuqing Wang,Yixuan Min,Junqing Li,Lili Zhang,Ting Zheng,Jun Shen,Yoshio Okamoto
A novel cellulose derivative bearing bulky 4-(2-benzothienyl)phenylcarbamate substituents ( Cel-1 ) was readily synthesized by carbamoylation followed by Suzuki–Miyaura coupling reaction. The corresponding coated-type chiral stationary phase (CSP) was prepared on basis of the derivative, and its chiral recognition ability was then evaluated by high-performance liquid chromatography (HPLC). The chiral recognition ability of the cellulose derivative was greatly influenced by introduction of the bulky benzothienyl pendants on the aromatic moieties of phenylcarbamates, compared with its analog with smaller groups. Many racemates, including the metal tris(acetylacetonate) complexes, chiral drug, and the analyte with axial chirality, were sufficiently separated with good enantioselectivities on Cel-1 . Some of them were even higher than those on the commercially powerful Chiralcel OD, which is also a coated-type CSP derived from cellulose phenylcarbamate derivative containing smaller 3,5-dimethyl pendants. The 1 H NMR and circular dichroism (CD) spectra of Cel-1 indicated that the obtained derivative possessed a regular higher order structure, and a strong cotton effect was observed within the absorption range of π-conjugated pendant at 350–500 nm. Impressively, the cellulose derivative bearing the bulky 4-(2-benzothienyl)phenylcarbamates exhibited good enantioselective fluorescence quenching behavior to the enantiomer pair of 1-phenylethylamine, probably suggesting its potential for the application as a chiral fluorescent sensor with high efficiency. The combination of the arrangement of bulky π-conjugated benzothienyl pendants on the phenylcarbamate moieties surrounding the helical backbone and the regular higher order structure of the polymer itself probably played a key role for this high chiral fluorescent recognition ability of Cel - 1 . The interaction sites of bulky 4-(2-benzothienyl)phenylcarbamate pendants in its excited state can exhibit higher enantioselective discrimination via fluorescent response to the chiral compound Q1 , whereas the chiral recognition ability of Cel-1 to the same compound in the ground state had no clear improvement.
危险品化学品经营许可证（带存储）