Photophysical Responses in Pt2Pb Clusters Driven by Solvent Interactions and Structural Changes in the PbII Environment

详细信息    查看全文

• 作者：Jes煤s R. Berenguer ; Elena Lalinde ; Antonio Mart铆n ; M. Teresa Moreno ; Santiago Ruiz ; Sergio S谩nchez ; Hamid R. Shahsavari
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：August 18, 2014
• 年：2014
• 卷：53
• 期：16
• 页码：8770-8785
• 全文大小：677K
• ISSN：1520-510X

文摘

Two types of Pt₂Pb luminescent clusters were successfully prepared by the reaction of [Pt(C₆F₅)(bzq)(OCMe₂)] (1) and [Pt(C₆F₅)(ppy)(dmso)] (2) with [Pb(SpyR-5)₂] (R = H, CF₃). Thus, whereas 5 (ppy, Spy) is generated through coordination of the pyridine-N atoms to the Pt centers, the formation of 3, 4 (bzq), and 6 (ppy, SpyCF₃) is accompanied by a formal thiolate transfer from Pb^II to Pt^II, keeping the two N atoms in the primary environment of the lead. In 5, the neutral Pb center adopts a rather stable and symmetrical 鈥淧t₂S₂鈥?coordination sphere supplemented by two Pb路路F_o contacts, whereas for the remaining species several pseudopolymorphs were found depending on the solvent (3, 4) and crystallization conditions (6). This structural diversity relies on changes in the coordination mode of the SpyR ligands (渭-魏S,N/渭-魏³S,N,S), intermetallic Pt鈥揚b bonds, and secondary intra- and intermolecular contacts induced by Pb鈥搒olvent binding. Notably, the changes, which entail a slight tuning of the stereochemical activity of the lone pair, have also a remarkable impact on the emissive state (³L鈥睠CT/³L鈥睱CT, SpyR 鈫?Pb,Pt/(CN) in nature). Clusters 3 and 4 display a distinct and fast reversible blue shift vapoluminescent response (4 shows also color changes) to donor solvents, correlated with changes in the environment of the Pb^II ion (asymmetric hemidirected to more symmetric holodirected) upon solvent binding and, additionally, in 4 with modifications in the crystal packing, as confirmed by XRD and supported by TD-DFT calculations. 5 and 6 do not show a vapoluminescent response. However, for 6, three different and interconvertible forms, a symmetrical form (yellow 6-y) and two asymmetrical forms with a rather short Pt鈥揚b bond (pale orange 6路acetone and orange 6-o), exhibiting different emissions were found. Notably, slow crystallization and low concentration favor the formation of the thermodynamically more stable yellow form, whereas fast crystallization gives rise to orange solids with a remarkable red shift of the emission. Interestingly, 6 also exhibits reversible mechanochromic color and luminescence changes.