- Synthesis and isolation of a homodimer of cadmium selenide nanocyrstals
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By size-selective precipitation homodimeric CdSe nanocyrstals could be isolated from a mixture of oligomers formed when monodisperse CdSe nanocrystals were linked by the bifunctional organic ligand, bis(acyl hydrazide). TEM images revealed a reproducible separation between CdSe particles of approximately a quarter of the particle diameter. This distance is consistent with the physical dimensions of the linker.
- Peng,Wilson,Alivisatos,Schultz
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- Coordination-driven nanosized lanthanide 'Molecular Lanterns' as luminescent chemosensors for the selective sensing of magnesium ions
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Novel cerium-based 'Molecular Lanterns' Ce-DBDS, Ce-DBBS and Ce-DBOS were achieved via self-assembly from bis-tridentate ligands H4DBDS, H 4DBBS and H4DBOS, respectively. Structure analysis of Ce-DBDS shows that six oxygen atoms of the ether bond groups on the ligands form a lantern-like cavity inside the compound. Thus the 'Molecular Lanterns' exhibit crown ether recognition behavior and could be applied in luminescent magnesium chemosensors. The restricted geometry constraints of the internal cavities provide high selectivities of the lantern-like probes towards the Mg2+ ion over other different-sized metal ions such as Al 3+, Li+, Ca2+, Na+, Ba2+ and K+. Ce-DBBS which contains three fully substituted benzyl groups exhibited better sensitivity by the cation-π interaction between Mg 2+ and the benzyl group, compared to the Ce-DBDS. However, Ce-DBOS can work as an artificial chemosensor for selective fluorescent detection of Al3+ rather than Mg2+, due to its cavity being much smaller than Ce-DBDS and Ce-DBBS.
- Zhao, Liang,Liu, Yang,He, Cheng,Wang, Jian,Duan, Chunying
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p. 335 - 343
(2014/01/06)
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- Oxidative coupling polymerization of bishydrazide for the synthesis of poly(diacylhydrazine): Oxidative preparation of oxidatively degradable polymer
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The oxidative coupling polymerization of bishydrazide is successfully performed to form poly(diacylhydrazine) (PDAH), which is an oxidatively degradable polymer. Oxone is an effective oxidant, and a mixture of an aprotic polar solvent, water, and acetonitrile or N,N-dimethylacetamide is necessary as the solvent. On treatment of PDAH with sodium hypochlorite solution or hydrogen peroxide, the PDAH is rapidly oxidized and degraded to the corresponding dicarboxylic acid. When hydrogen peroxide is used as the oxidant, the addition of acetonitrile and potassium carbonate is necessary for effective degradation. PDAH exhibits high thermal stability in air and a high Tg value. No oxidation is observed in air. Thus, PDAH is an oxidatively degradable high-performance polymer that is stable toward oxygen.
- Nagashima, Kentaro,Kihara, Nobuhiro,Iino, Yusuke
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p. 4230 - 4238
(2012/11/13)
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