Jiang Yao, Park Jinhee, Tan Peng, Feng Liang, Liu Xiao-Qin, Sun Lin-Bing, Zhou Hong-Cai
State Key Laboratory of Materials-Oriented Chemical Engineering, Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), College of Chemical Engineering , Nanjing Tech University , Nanjing 210009 , China.
Department of Emerging Materials Science , Daegu Gyeongbuk Institute of Science and Technology , Daegu 42988 , Republic of Korea.
J Am Chem Soc. 2019 May 22;141(20):8221-8227. doi: 10.1021/jacs.9b01380. Epub 2019 Apr 22.
Photoresponsive metal-organic polyhedra (PMOPs) have attracted expanding interests due to their modular nature with tunable functionality and variable responsive behaviors tailored conveniently by external-stimulus. However, their photoresponsive efficiency is often compromised after activation because of desorption-triggered aggregation into bulk PMOPs, which limits their utility in stimuli-responsive applications. Here, we report a case system that can overcome the aggregation problem and achieve maximized photoresponsive efficiency by polyhedral isolation in the nanoscaled spaces of mesoporous silica (MS). Through confinement, amount-controllable PMOPs are well dispersed in the nanoscaled spaces of MS, avoiding aggregation that commonly takes places in bulk PMOPs. Furthermore, reversible trans/ cis isomerization of photoresponsive groups can be realized freely during ultraviolet/visible light irradiation, maximizing control over photoresponsive guest adsorption behaviors. Remarkably, after trans/ cis isomerization, the confined PMOP-1 shows 48.2% of change in adsorption amount for propene with small molecular size and 43.9% for brilliant blue G (BBG) with large molecular size, which is significantly higher than that over bulk PMOP-1 with 11.2% for propene and 7.8% for BBG, respectively. Therefore, our work paves a way for the design and construction of multifunctional composite materials toward efficient stimuli-responsive needs.
光响应性金属有机多面体（PMOPs）因其模块化性质、可调功能以及可通过外部刺激方便地定制可变响应行为而吸引了越来越多的关注。然而，由于解吸引发的聚集形成块状PMOPs，其光响应效率在激活后常常受到影响，这限制了它们在刺激响应应用中的效用。在此，我们报道了一个案例系统，该系统可以通过在介孔二氧化硅（MS）的纳米级空间中进行多面体隔离来克服聚集问题并实现最大化的光响应效率。通过限制，数量可控的PMOPs很好地分散在MS的纳米级空间中，避免了在块状PMOPs中常见的聚集。此外，在紫外光/可见光照射期间，可以自由实现光响应基团的可逆反式/顺式异构化，从而最大限度地控制光响应客体的吸附行为。值得注意的是，在反式/顺式异构化后，受限的PMOP-1对小分子丙烯的吸附量变化为48.2%，对大分子亮蓝G（BBG）的吸附量变化为43.9%，这分别显著高于块状PMOP-1对丙烯的11.2%和对BBG的7.8%。因此，我们的工作为设计和构建满足高效刺激响应需求的多功能复合材料铺平了道路。
