Luminescent Properties of Metal-Organic Framework MOF-5: Relativistic Time-Dependent Density Functional Theory Investigations
Luminescent Properties of Metal-Organic Framework MOF-5: Relativistic Time-Dependent Density Functional Theory Investigations
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金属有机骨架MOF-5的发光特性：相对论时变密度泛函理论研究
DOI：
10.1021/ic301771b
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发表时间：
2012-11-19
影响因子：
4.6
通讯作者：
Qiu, Jieshan
中科院分区：
文献类型：
--
作者：
Ji, Min;Lan, Xin;Qiu, Jieshan
采用相对论密度泛函理论（DFT）和含时密度泛函理论（TDDFT）研究了金属有机骨架MOF-5的电子激发态和发光性质。用相对论密度泛函理论计算了MOF-S基态的几何构型、红外光谱和紫外-可见光谱，实验结果与理论结果吻合较好。前线分子轨道和电子构型表明，MOF-5的发光机制为配体-配体电荷转移（LLCT），即pi* -> pi，而不是Bordiga等人提出的ZnO量子点（QD）发光机制。结果表明，Zn_4O_（13）QD是刚性的，而配体BDC ~（2-）是非刚性的。此外，计算的发射带与实验结果吻合良好，与配体H2 BDC的发射带相似。组合的结果证实，M0 F-5的发光机制应为LLCT，配体到金属的电荷转移几乎没有混合。MOF-5发光的原因是由锌、氧、碳和苯环组成的六元环之间的良好共面性解释的。
The electronically excited state and luminescence property of metal organic framework MOF-5 were investigated using relativistic density functional theory (DFT) and time-dependent DFT (TDDFT). The geometry, IR spectra, and UV-vis spectra of MOF-S in the ground state were calculated using relativistic DFT, leading to good agreement between the experimental and theoretical results. The frontier molecular orbitals and electronic configuration indicated that the luminescence mechanism in MOF-5 follows ligand-to-ligand charge transfer (LLCT), namely, pi* -> pi, rather than emission with the ZnO quantum dot (QD) proposed by Bordiga et al. The geometry and IR spectra of MOF-5 in the electronically excited state have been calculated using the relativistic TDDFT and compared with those for the ground state. The comparison reveals that the Zn4O13 QD is rigid, whereas the ligands BDC2- are nonrigid. In addition, the calculated emission band of MOF-5 is in good agreement with the experimental result and is similar to that of the ligand H2BDC. The combined results confirmed that the luminescence mechanism for MOF-5 should be LLCT with little mixing of the ligand-to-metal charge transfer. The reason for the MOF-5 luminescence is explained by the excellent coplanarity between the six-membered ring consisting of zinc, oxygen, carbon, and the benzene ring.