A ratiometric fluorescent probe for hypochlorous acid determination: Excitation and the dual-emission wavelengths at NIR region.

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. Employing the isosbestic absorption point at 730nm as an excitation wavelength, a ratiometric fluorescent sensing mode with two long emission wavelengths at 760nm and 820nm was acquired, and thus the probe displayed significant behavior with both the excitation wavelength and the dual-emission wavelengths located at NIR (650-900nm) region exclusively. Also, the probe showed excellent performance in high sensitivity and good selectivity towards HClO over other reactive oxygen species and a wide variety of coexist species in biological pH condition and had been successfully used to detect hypochlorous acid in serum samples and tap water samples.

Neutral nickel(II) phthalocyanine as a stable catalyst for visible-light-driven hydrogen evolution from water.

Neutral 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.

The microfluidic synthesis of composite hollow microfibers for K+-responsive controlled release based on a host-guest system.

A 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. Thus, the interspace size becomes larger, resulting in a rapid increase in the release rate of encapsulated drugs. When the ambient K+ concentration is decreased, the interspace size becomes smaller due to isothermal swelling of microspheres caused by the decreased amount of host-guest complexes, resulting in a decrease in the release rate. The K+-responsive drug release behaviors are reversible. This kind of K+-responsive hollow microfiber with K+-concentration-dependent controlled-release properties provides a new mode in the design of more rational drug delivery systems, which are highly attractive for biomedical applications.

A Noble-Metal-Free Nickel(II) Polypyridyl Catalyst for Visible-Light-Driven Hydrogen Production from Water.

The 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. The photocatalytic results demonstrate that the nickel(II) polypyridyl catalyst can act as a more effective catalyst than the commonly utilized [Co(bpy)3 ](2+). This study may offer a new paradigm for constructing simple and noble-metal-free catalysts for photocatalytic hydrogen production.

A heptamethine cyanine-based colorimetric and ratiometric fluorescent chemosensor for the selective detection of Ag+ in an aqueous medium.

A 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.

Diethyl 2-{4-diethyl-amino-2-[(dimethyl-carbamothio-yl)-oxy]benzyl-idene}malonate.

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,ß-unsaturated malonate side chain makes a dihedral angle of 8.73 (10)° with the central benzene ring, while the other carbonyl group makes a dihedral angle of 81.52 (8)°.

Periodic mesoporous organosilica materials: self-assembly of carbamothioic acid-bridged organosilane precursors.

A 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. They are also structurally well-ordered with a high organosilica precursor content, and the carbamothioic acid groups are thermally stable up to 250 degrees C. Furthermore, the organosilica materials exhibit hydrothermal stability in basic solution.

Synthesis of large-pore urea-bridged periodic mesoporous organosilicas.

In 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.

Novel inorganic-organic hybrid fluorescence chemosensor derived from SBA-15 for copper cation.

A 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.