An interesting ratiometric fluorescent probe with unique optical performance was reported in this work. By modifying on the bridge-head of heptamethine cyanine chromophore with an N-phenyl-N'-ethylene amine thiourea substituent as a chemodosimetric recognition unit, the probe exhibited ratiometric fluorescent response towards hypochlorous acid (HClO). Upon addition of HClO, the absorbance spectra showed a great red shift as large as 150nm from 650nm to 800nm.
View Article and Find Full Text PDFA novel type of composite hollow microfiber with K-responsive controlled-release characteristics based on a host-guest system is prepared by embedding K-responsive poly(N-isopropylacrylamide-co-acryloylamidobenzo-15-crown-5) (P(NIPAM-co-AAB15C5)) microspheres in the wall of poly(lactic-co-glycolic acid) (PLGA) microfibers as "micro-valves" using a controllable microfluidic approach. By adjusting the volume change of microspheres in response to the environmental K concentration, the release rate of the encapsulated drug molecules from the composite hollow microfibers can be flexibly regulated owing to the change in the interspace size between the microfiber wall and microspheres. When the environmental K concentration is increased, due to the formation of stable 2 : 1 "sandwich-type" host-guest complexes of 15-crown-5 units and K ions, P(NIPAM-co-AAB15C5) microspheres change from a swollen state to a shrunken state.
View Article and Find Full Text PDFNeutral nickel(ii) phthalocyanine was found to be an efficient and stable catalyst for photocatalytic H2 evolution from water when coupled with an iridium complex as the photosensitizer and triethanolamine as the sacrificial electron donor. The result shows that the Ni-N sigma bond can enhance the stability of the catalyst.
View Article and Find Full Text PDFThe complex [Ni(bpy)3](2+) (bpy=2,2'-bipyridine) is an active catalyst for visible-light-driven H2 production from water when employed with [Ir(dfppy)2 (Hdcbpy)] [dfppy=2-(3,4-difluorophenyl)pyridine, Hdcbpy=4-carboxy-2,2'-bipyridine-4'-carboxylate] as the photosensitizer and triethanolamine as the sacrificial electron donor. The highest turnover number of 520 with respect to the nickel(II) catalyst is obtained in a 8:2 acetonitrile/water solution at pH 9. The H2 -evolution system is more stable after the addition of an extra free bpy ligand, owing to faster catalyst regeneration.
View Article and Find Full Text PDFA highly selective and sensitive ratiometric fluorescent chemosensor for Ag(+) in aqueous solution was developed, in a linear range of 0.6 × 10(-7) to 50 × 10(-7) mol L(-1), based on a A-Ag(+)-A binding mode with a heptamethine cyanine motif containing one adenine moiety.
View Article and Find Full Text PDFActa Crystallogr Sect E Struct Rep Online
July 2011
In the title compound, C(21)H(30)N(2)O(5)S, the plane of the dimeth-yl-thio-carbamic group makes a dihedral angle of 78.41 (7)° with the central benzene ring. One of the carbonyl groups in the α,β-unsaturated malonate side chain makes a dihedral angle of 8.
View Article and Find Full Text PDFA new series of carbamothioic acid-containing periodic mesoporous organosilica (PMO) materials has been synthesized by a direct cocondensation method, in which an organosilica precursor N,S-bis[3-(triethoxysilyl)propyl]carbamothioic acid (MI) is treated with tetraethyl orthosilicate (TEOS), and the nonionic surfactant Pluronic 123 (P123) is used as a template under acidic conditions in the presence of inorganic additives. Moreover, the synthesis of the PMO material consisting of the MI precursor without TEOS has been realized. These novel PMO materials have large surface areas, well-ordered mesoporous structures, hollow fiberlike morphologies, and thick walls.
View Article and Find Full Text PDFIn this article we report the successful synthesis of a new class of periodic mesoporous organosilicas (PMOs) with a urea-bridged organosilica precursor under acid-catalyzed and inorganic-salt-assisted conditions. The large-pore hybrid materials have an ordered mesostructure with uniform pore size distributions, excellent thick framework walls, thermal stability, and specific functional groups. The composition of the mesoporous organosilicas was characterized by FTIR spectroscopy, (13)C cross-polarization magic-angle spinning (CP MAS) NMR spectroscopy, and (29)Si MAS NMR spectroscopy.
View Article and Find Full Text PDFA novel mesoporous SBA-15 type of hybrid material (3-trimethoxysilylpropyl)[4-(2-hydroxyphenyl)methylene] benzenesulfonamide (Schiff-SBA-15) has been obtained by co-condensation of tetraethyl orthosilicate and the organosilane, and the result of XRD confirms the order hexagonal structure of the composite. This hybrid mesoporous material is fluorescent-active, exhibiting high selectivity for sensing Cu2+ in polar solution. The remarkable fluorescence quenching in emission spectrum upon the addition of Cu2+ is attributed to the intramolecular charge transfer after the formation of a coordinate complex of a large conjugate system and Cu2+ ions.
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