Phosphorescent Modulation of Metallophilic Clusters and Recognition of Solvents through a Flexible Host-Guest Assembly: A Theoretical Investigation.
Phosphorescent Modulation of Metallophilic Clusters and Recognition of Solvents through a Flexible Host-Guest Assembly: A Theoretical Investigation.
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通过灵活的主客体组装对亲金属簇进行磷光调节和溶剂识别：理论研究
DOI：
10.3390/nano8090685
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发表时间：
2018-09-02
期刊：
影响因子：
--
通讯作者：
Zuo GF
中科院分区：
文献类型：
--
作者：
Li ZF;Yang XP;Li HX;Zuo GF
采用MP2 （Møller - plesset微扰理论的二阶近似）和DFT/TD-DFT（密度泛函理论/时间依赖理论）研究了具有高荧光性质的亲金纳米材料的主簇[Au(NHC)2]+⋅⋅⋅[M(CN)2]−⋅⋅⋅[Au(NHC)2]+ （NHC = n -杂环碳，M = Au, Ag）。实验中团簇的磷光量子产率顺序由它们的μS1/ΔES1−T1值顺序（S0→S1跃迁偶极子，S1和T1激发态之间的分裂能）来证明。客体溶剂（S1: CH3OH, S2: CH3CH2OH, S3: H2O）的系统变化不仅阐明了它们对亲金属相互作用和磷光的影响，而且还作为探针来研究宿主的识别能力。模拟结果表明，亲金相互作用主要是静电作用，客体可以通过相互氢键相互作用微妙地调节宿主体的几何形状，特别是亲金Au⋅⋅⋅⋅M距离。预测宿主的磷光光谱在极性溶剂下发生蓝移，并发现从HOMO（最高占据分子轨道）到LUMO（最低未占据分子轨道）的激发是导致宿主和主客体配合物中金属到配体电荷转移（3MLCT）特征的原因。研究结果可以作为设计有前途的蓝光磷光材料和功能材料的线索。
MP2 (Second order approximation of Møller–Plesset perturbation theory) and DFT/TD-DFT (Density functional theory/Time-dependent_density_functional_theory) investigations have been performed on metallophilic nanomaterials of host clusters [Au(NHC)2]+⋅⋅⋅[M(CN)2]−⋅⋅⋅[Au(NHC)2]+ (NHC = N-heterocyclic carbene, M = Au, Ag) with high phosphorescence. The phosphorescence quantum yield order of clusters in the experiments was evidenced by their order of μS1/ΔES1−T1 values (: S0 → S1 transition dipole, : splitting energy between the lowest-lying singlet S1 and the triplet excited state T1 states). The systematic variation of the guest solvents (S1: CH3OH, S2: CH3CH2OH, S3: H2O) are employed not only to illuminate their effect on the metallophilic interaction and phosphorescence but also as the probes to investigate the recognized capacity of the hosts. The simulations revealed that the metallophilic interactions are mainly electrostatic and the guests can subtly modulate the geometries, especially metallophilic Au⋅⋅⋅M distances of the hosts through mutual hydrogen bond interactions. The phosphorescence spectra of hosts are predicted to be blue-shifted under polar solvent and the excitation from HOMO (highest occupied molecular orbital) to LUMO (lowest unoccupied molecular orbital) was found to be responsible for the 3MLCT (triplet metal-to-ligand charge transfer) characters in the hosts and host-guest complexes. The results of investigation can be introduced as the clues for the design of promising blue-emitting phosphorescent and functional materials.