Luminescence from the trans-Dioxotechnetium(V) Chromophore

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• 作者：Andrew S. Del Negro ; Zheming Wang ; Carl J. Seliskar ; William R. Heineman ; B. Patrick Sullivan ; Sean E. Hightower ; Timothy L. Hubler ; and Samuel A. Bryan
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：November 2, 2005
• 年：2005
• 卷：127
• 期：43
• 页码：14978 - 14979
• 全文大小：52K
• 年卷期：v.127,no.43(November 2, 2005)
• ISSN：1520-5126

文摘

The luminescence of trans-[TcO₂(L)₄]⁺ (L = pyridine (py) or picoline (pic)) and trans-[TcO₂(CN)₄]^3- at room and low temperature is described and represents the first example of room temperature excited-state luminescence observed for Tc complexes. At room temperature, the complexes exhibited broad luminescence with emission maxima ranging from 745 to 780 nm. Analogous to the Re complexes (emission at 635-655 nm), the low-temperature emission spectra of microcrystalline samples of [TcO₂(py)₄]BPh₄ and [TcO₂(pic)₄]BPh₄ display the characteristic progressions of the symmetric O=Tc=O and Tc-L stretching modes. DFT/TDDFT calculations were performed on the trans-[MO₂(L)₄]⁺ (M = Re, Tc) congeners and predicted the dioxotechnetium emission to be 0.41 eV lower in energy than its Re analogue. Low-temperature lifetimes (8 K) ranging from 15 to 1926 s/entities/mgr.gif">s for the series of Tc complexes are consistent with the Re analogues.