Zinc Chalcogenolate Complexes as Precursors to ZnE and Mn/ZnE (E = S, Se) Clusters

The ternary clusters (tmeda)6Zn14–xMnxS13Cl2 (1a–d) and (tmeda)6Zn14–xMnxSe13Cl2 (2a–d), (tmeda = N,N,N′,N′-tetramethylethylenediamine; x ≈ 2–8) and the binary clusters (tmeda)6Zn14E13Cl2 (E = S, 3; Se, 4;) have been isolated by reacting (tmeda)­Zn­(ESiMe3)2 with Mn­(II) and Zn­(II) salts. Single crystal X-ray analysis of the complexes confirms the presence of the six “(tmeda)­ZnE2” units as capping ligands that stabilize the clusters, and distorted tetrahedral geometry around the metal centers. Mn­(II) is incorporated into the ZnE framework by substitution of Zn­(II) ions in the cluster. The polynuclear complexes (tmeda)6Zn12.3Mn1.7S13Cl2 1a, (tmeda)6Zn12.0Mn2.0Se13Cl2 2a, and (tmeda)6Zn8.4Mn5.6Se13Cl2 2d represent the first examples of “Mn/ZnE” clusters with structural characterization and indications of the local chemical environment of the Mn­(II) ions. The incorporation of higher amounts of Mn into 1d and 2d has been confirmed by elemental analysis. Density functional theory (DFT) calculations indicate that replacement of Zn with Mn is perfectly feasible and at least partly allows for the identification of some sites preferred by the Mn­(II) metals. These calculations, combined with luminescence studies, suggest a distribution of the Mn­(II) in the clusters. The room temperature emission spectra of clusters 1c–d display a significant red shift relative to the all zinc cluster 3, with a peak maximum centered at 730 nm. Clusters 2c–d display a peak maximum at 640 nm in their emission spectra.本研究通过将(tmeda)Zn(ESiMe₃)₂与Mn(II)和Zn(II)盐反应，成功分离得到三元团簇(tmeda)₆Zn₁₄–ₓMnₓS₁₃Cl₂ (1a–d)和(tmeda)₆Zn₁₄–ₓMnₓSe₁₃Cl₂ (2a–d)（其中tmeda为N,N,N′,N′-四甲基乙二胺，x≈2–8），以及二元团簇(tmeda)₆Zn₁₄E₁₃Cl₂（E=S时记为3，E=Se时记为4）。 对上述配合物的单晶X射线衍射分析证实，六个“(tmeda)ZnE₂”单元作为封端配体稳定了团簇结构，且金属中心周围呈现畸变四面体几何构型。Mn(II)通过取代团簇中的Zn(II)离子，被嵌入ZnE骨架之中。 多核配合物(tmeda)₆Zn₁₂.₃Mn₁.₇S₁₃Cl₂（1a）、(tmeda)₆Zn₁₂.₀Mn₂.₀Se₁₃Cl₂（2a）与(tmeda)₆Zn₈.₄Mn₅.₆Se₁₃Cl₂（2d）是首例获得结构表征、并揭示了Mn(II)离子局部化学环境的“Mn/ZnE”类团簇。元素分析结果证实，1d与2d中掺入了更高含量的Mn。 密度泛函理论（DFT）计算表明，用Mn取代Zn完全可行，且该计算至少部分明确了Mn(II)金属偏好的结合位点。结合发光研究的计算结果显示，Mn(II)在团簇中存在分布模式。 相较于全锌团簇3，团簇1c–d的室温发射光谱发生显著红移，峰值中心位于730 nm；而团簇2c–d的发射光谱峰值中心则为640 nm。