Photophysics and Luminescence Spectroelectrochemistry of [Tc(dmpe)3]+/2+ (dmpe = 1,2-bis(dimethylphosphino)ethane)

详细信息    查看全文

• 作者：Sayandev Chatterjee ; Andrew S. Del Negro ; Frances N. Smith ; Zheming Wang ; Sean E. Hightower ; B. Patrick Sullivan ; William R. Heineman ; Carl J. Seliskar ; Samuel A. Bryan
• 刊名：Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：December 5, 2013
• 年：2013
• 卷：117
• 期：48
• 页码：12749-12758
• 全文大小：519K
• 年卷期：v.117,no.48(December 5, 2013)
• ISSN：1520-5215

文摘

The ligand-to-metal charge transfer (LMCT) excited state luminescence of [Tc(dmpe)₃]²⁺ (dmpe is 1,2-bis-(dimethylphosphino)ethane) has been measured in solution at room temperature and is compared to its Re analogue. Surprisingly, both [M(dmpe)₃]²⁺* (M = Re, Tc) species have extremely large excited-state potentials (ESPs) as oxidants, the highest for any simple coordination complex of a transition metal. Furthermore, this potential is available using a photon of visible light (calculated for M = Tc; E掳鈥? = +2.48 V versus SCE; 位_max = 585 nm). Open shell time-dependent density functional theory (TDDFT) calculations support the assignment of the lowest energy transition in both the technetium and rhenium complexes to be a doublet鈥揹oublet process that involves predominantly LMCT (dmpe-to-metal) character and is in agreement with past assignments for the Re system. As expected for highly oxidizing excited state potentials, quenching is observed for the excited states of both the rhenium and technetium complexes. Stern鈥揤olmer analysis resulted in quenching parameters for both the rhenium and technetium complexes under identical conditions and are compared using Rehm鈥揥eller analysis. Of particular interest is the fact that both benzene and toluene are oxidized by both the Re and Tc systems.