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6924278 
Journal Article 
Photophysics and Luminescence Spectroelectrochemistry of [Tc(dmpe)(3)](+/2+) (dmpe=1,2-bis(dimethylphosphino)ethane) 
Chatterjee, S; Del Negro, AS; Smith, FN; Wang, Z; Hightower, SE; Sullivan, BP; Heineman, WR; Seliskar, CJ; Bryan, SA; , 
2013 
1 
Journal of Physical Chemistry A
ISSN: 1089-5639
EISSN: 1520-5215 
AMER CHEMICAL SOC 
WASHINGTON 
117 
48 
12749-12758 
English 
24256024 
WOS:000328100800008 
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 degrees'* = +2.48 V versus SCE; lambda(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-doublet 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-Volmer analysis resulted in quenching parameters for both the rhenium and technetium complexes under identical conditions and are compared using Rehm-Weller analysis. Of particular interest is the fact that both benzene and toluene are oxidized by both the Re and Tc systems.