Tuning Fluorescent Molecules by Inclusion in a Metal–Organic Framework: An Experimental and Computational Study
Tuning Fluorescent Molecules by Inclusion in a Metal–Organic Framework: An Experimental and Computational Study
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DOI：
10.1002/cplu.201200245
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发表时间：
2012-12
期刊：
影响因子：
3.4
通讯作者：
Dongpeng Yan;G. Lloyd;A. Delori;W. Jones;X. Duan
中科院分区：
文献类型：
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作者：
Dongpeng Yan;G. Lloyd;A. Delori;W. Jones;X. Duan
金属有机骨架(MOF)中的荧光分子为发展发光主客体材料提供了新的机会。报道了1，4-二对氰基苯乙烯基苯(BPCB)和1，4-二(5-苯并恶唑-2-基)苯(BPOB)两种线性π偶联荧光分子。与纯客体分子和基质相比，得到的bpcb@MOF-5和bpob@MOF-5具有可调的蓝色荧光性质(发射波长、荧光寿命和量子产率)。此外，采用溶剂挥发法制备了bpcb@MOF-5和bpob@MOF-5薄膜。MOF基薄膜表现出清晰的偏振蓝光发射，荧光各向异性约为0.15，表明MOF基质中BPCB和BPOB发色团均匀分散，取向良好。此外，周期密度泛函理论(DFT)计算表明，组装的光活性分子MOF体系在光激发过程中具有客体和主体骨架之间的能量和/或电子转移，这表明包裹的分子可以进一步改变主体MOF材料的电子结构。在对荧光客体@MOF体系的实验和理论研究相结合的基础上，本研究不仅提出了一种制备具有可调谐发光的MOF基粉末和薄膜的可行方法，而且还提供了限制在MOF基质中的光活性分子的几何和电子结构的详细信息。
Fluorescent molecules included within a metal–organic framework (MOF) offer a new opportunity to develop luminescent host–guest materials. Two linear π-conjugated fluorescent molecules, 1,4-bis-p-cyanostyrylbenzene (bpcb) and 1,4-bis(5-phenyloxazol-2-yl)benzene (bpob), incorporated into MOF-5 systems are reported. The as-obtained bpcb@MOF-5 and bpob@MOF-5 displayed tunable blue fluorescent properties (emission wavelength, fluorescent lifetime, and quantum yield) compared with the pure guest molecule and host matrix. Moreover, bpcb@MOF-5 and bpob@MOF-5 thin films were fabricated by the solvent-evaporation method. The MOF-based thin films exhibit well-defined polarized blue emission with a fluorescent anisotropy of approximately 0.15, demonstrating the uniform dispersion and well-oriented bpcb and bpob chromophores within the MOF matrix. Furthermore, a periodic density functional theoretical (DFT) calculation demonstrates that the photoactive molecule assembled MOFs systems feature energy and/or electron transfer between the guest and host framework during the photoexcitation process, thus suggesting that the encapsulated molecule can further modify the electronic structure of the host MOF materials. Based on the combination of experimental and theoretical studies on the fluorescent guests@MOF systems, this study not only presents a feasible method for fabricating MOF-based powders and films with tunable luminescence, but also gives detailed information on the geometric and electronic structures of the photoactive molecule confined within the MOF matrix.