Li Zhi-Feng, Yang Xiao-Ping, Li Hui-Xue, Zuo Guo-Fang
College of Chemical Engineering and Technology, Key Laboratory for New Molecule Design and Function of Gansu Universities, Tianshui Normal University, Tianshui 741001, China.
School of Electronic Information and Electrical Engineering, Tianshui Normal University, Tianshui 741001, China.
Nanomaterials (Basel). 2018 Sep 2;8(9):685. doi: 10.3390/nano8090685.
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 /Δ values ( μ S 1 : S₀ → S₁ transition dipole, ∆ E S 1 - T 1 : splitting energy between the lowest-lying singlet S₁ and the triplet excited state T₁ states). The systematic variation of the guest solvents (: CH₃OH, : CH₃CH₂OH, : 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.
已对具有高磷光性的主体簇[Au(NHC)₂]⁺⋅⋅⋅[M(CN)₂]⋅⋅⋅[Au(NHC)₂]⁺（NHC = N-杂环卡宾，M = Au、Ag）的亲金属纳米材料进行了MP2（莫勒-普莱塞特微扰理论的二阶近似）和DFT/TD-DFT（密度泛函理论/含时密度泛函理论）研究。实验中簇的磷光量子产率顺序由其/Δ值（μS₁：S₀→S₁跃迁偶极矩，∆ES₁ - T₁：最低单重态S₁与三重激发态T₁之间的分裂能）顺序证明。使用客体溶剂（：CH₃OH、：CH₃CH₂OH、：H₂O）的系统变化不仅是为了阐明它们对亲金属相互作用和磷光的影响，还作为研究主体识别能力的探针。模拟结果表明，亲金属相互作用主要是静电作用，客体可通过相互氢键相互作用微妙地调节主体的几何结构，尤其是主体的亲金属Au⋅⋅⋅M距离。预计主体的磷光光谱在极性溶剂下会发生蓝移，并且发现从HOMO（最高占据分子轨道）到LUMO（最低未占据分子轨道）的激发是主体和主体 - 客体络合物中³MLCT（三重态金属到配体电荷转移）特征的原因。研究结果可作为设计有前景的蓝色发光磷光和功能材料的线索。
