Alberding Brian G, Chisholm Malcolm H, Chou Yi-Hsuan, Gallucci Judith C, Ghosh Yagnaseni, Gustafson Terry L, Patmore Nathan J, Reed Carly R, Turro Claudia
Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1185, USA.
Inorg Chem. 2009 May 18;48(10):4394-9. doi: 10.1021/ic900092c.
The preparation and characterization (elemental analysis, (1)H NMR, and cyclic voltammetry) of the new compounds MM(TiPB)(4), where MM = MoW and W(2) and TiPB = 2,4,6-triisopropylbenzoate, are reported. Together with Mo(2)(TiPB)(4), previously reported by Cotton et al. (Inorg. Chem. 2002, 41, 1639), the new compounds have been studied by electronic absorption, steady-state emission, and transient absorption spectroscopy (femtosecond and nanosecond). The compounds show strong absorptions in the visible region of the spectrum that are assigned to MMdelta to arylcarboxylate pi* transitions, (1)MLCT. Each compound also shows luminescence from two excited states, assigned as the (1)MLCT and (3)MMdeltadelta* states. The energy of the emission from the (1)MLCT state follows the energy ordering MM = Mo(2) > MoW > W(2), but the emission from the (3)MMdeltadelta* state follows the inverse order: MM = W(2) > MoW > Mo(2). Evidence is presented to support the view that the lower energy emission in each case arises from the (3)MMdeltadelta* state. Lifetimes of the (1)MLCT states in these systems are approximately 0.4-6 ps, whereas phosphorescence is dependent on the MM center: Mo(2) approximately 40 micros, MoW approximately 30 micros, and W(2) approximately 1 micros.
报道了新化合物MM(TiPB)₄（其中MM = MoW和W₂，TiPB = 2,4,6 - 三异丙基苯甲酸酯）的制备及其表征（元素分析、¹H NMR和循环伏安法）。与Cotton等人之前报道的Mo₂(TiPB)₄（《无机化学》2002年，41卷，1639页）一起，通过电子吸收、稳态发射和瞬态吸收光谱（飞秒和纳秒）对这些新化合物进行了研究。这些化合物在光谱的可见光区域显示出强烈吸收，归因于MMδ到芳基羧酸酯π跃迁，即¹MLCT。每种化合物还显示出来自两个激发态的发光，分别归属于¹MLCT和³MMδδ态。来自¹MLCT态的发射能量遵循能量顺序MM = Mo₂ > MoW > W₂，但来自³MMδδ态的发射遵循相反顺序：MM = W₂ > MoW > Mo₂。提供了证据来支持这样的观点，即每种情况下较低能量的发射源自³MMδδ态。这些体系中¹MLCT态的寿命约为0.4 - 6皮秒，而磷光则取决于MM中心：Mo₂约为40微秒，MoW约为30微秒，W₂约为1微秒。
