Synthesis, Structure, and Photophysical Properties of Mo2(NN)4 and Mo2(NN)2(TiPB)2, Where NN = N,N′-Diphenylphenylpropiolamidinate and TiPB = 2,4,6-Triisopropylbenzoate

详细信息    查看全文

• 作者：Changcheng Jiang ; Philip J. Young ; Christopher B. Durr ; Thomas F. Spilker ; Malcolm H. Chisholm
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 20, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：5836-5844
• 全文大小：484K
• 年卷期：0
• ISSN：1520-510X

文摘

Two dimolybdenum compounds featuring amidinate ligands with a C≡C bond, Mo₂(NN)₄ (I), where NN = N,N′-diphenylphenylpropiolamidinate, and trans-Mo₂(NN)₂(TⁱPB)₂ (II), where TⁱPB = 2,4,6-triisopropylbenzoate, have been prepared and structurally characterized by single-crystal X-ray crystallography. Together with Mo₂(DAniF)₄ (III), where DAniF = N,N′-bis(p-anisyl)formamidinate, all three compounds have been studied with steady-state UV–vis, IR, and time-resolved spectroscopy methods. I and II display intense metal to ligand charge transfer (MLCT). Singlet state (S₁) lifetimes of I–III are determined to be 0.7, 19.1, and 2.0 ps, respectively. All three compounds have long-lived triplet state (T₁) lifetimes around 100 μs. In femtosecond time-resolved infrared (fs-TRIR) experiments, one ν(C≡C) band is observed at the S₁ state for I but two for II, which indicate different patterns of charge distribution. The electron would have to be localized on one NN ligand in I and partially delocalized over two NN ligands in II to account for the observations. The result is a standard showcase of excited-state mixed valence in coordination compounds.