Competitive photochemical reactivity in a self-assembled monolayer on a colloidal gold cluster
Competitive photochemical reactivity in a self-assembled monolayer on a colloidal gold cluster
复制标题
DOI：
10.1021/ja003180l
复制
发表时间：
2001-02-21
影响因子：
15
通讯作者：
Fox, MA
中科院分区：
文献类型：
--
作者：
Hu, J;Zhang, J;Fox, MA
通过在纳米颗粒金胶体上沉积6-硫代己基-3-硝基-4-（4 '-二苯乙烯氧基甲基）-苯甲酸酯（1）的自组装单层（SAM）产生的壳-核簇2保留了反式-二苯乙烯和邻硝基苄基醚部分的正常溶液相光反应性，但显示淬灭的荧光。最近邻聚集弱1绑定到大致球形的胶体金颗粒（簇2）比类似的芪类化合物：绑定到一个平面的金表面。与所观察到的作为SAM附加在平面金表面上的二苯乙烯基烷基硫化物的光化学反应性不同，存在于这些壳-核纳米复合材料2中的发色团表现出有效的反式至顺式光异构化和阻断的[2 + 2]光二聚化。波长选择性的光异构化和photocleavage被证明是难以捉摸的，但三倍敏化的几何异构化发生没有光释放的连接基团。
A shell-core cluster 2 produced by depositing a self-assembled monolayer (SAM) of 6-thiohexyl-3-nitro-4-(4'-stilbenoxymethyl)-benzoate (1) on a nanoparticulate gold colloid preserves normal solution-phase photoreactivity of the trans-stilbene and o-nitrobenzyl ether moieties, but shows quenched fluorescence. Nearest-neighbor aggregation is weaker for 1 bound to the roughly spherical colloidal gold particle (in cluster 2) than for analogous stilbenoids: bound to a planar gold surface. Unlike the observed photochemical reactivity of stilbenylalkyl sulfides appended as SAMs on planar gold surfaces, the chromophores present in these shell-core nanocomposites 2 exhibit efficient trans-to-cis photoisomerization and blocked [2 + 2] photodimerization. Wavelength selectivity for photoisomerization and photocleavage proved to be elusive, but tripler sensitization of the geometric isomerization took place without photorelease of the attached group.