Highly oxidizing excited states of Re and Tc complexes.
ABSTRACT Like the Re analogue, the ligand-to-metal charge transfer (LMCT) excited-state of [Tc(dmpe)3]2+ (dmpe is bis-1,2-(dimethylphosphino)ethane) is luminescent in solution at room temperature. Surprisingly, both [M(dmpe)3]2+* 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 = Re(Tc); E1/2* = +2.61(2.52) V versus SCE; lambdamax = 526(585) nm). Using a Rehm-Weller analysis with a series of aromatic hydrocarbons as electron-transfer quenchers, E1/2(Re2+*/Re+) has been determined to be 2.58 V, in good agreement with the calculated value. Both [M(dmpe)3]2+* species are quenched by chloride ion and both can function as excited-state oxidants in water solution.
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Article: trans-K(3)[TcO(2)(CN)(4)].[Show abstract] [Hide abstract]
ABSTRACT: The structure of the title compound, tripotassium trans-tetra-cyanidodioxidotechnetate(V), is isotypic with its Re analogue. The [TcO(2)(CN)(4)](3-)trans-tetra-cyanido-dioxido-technetate anion has a slightly distorted octa-hedral configuration. The Tc atom is located on a center of inversion and is bound to two O atoms in axial and to four cyanide ligands in equatorial positions. The Tc-O distance is consistent with a double-bond character. The two potassium cations, one located on a center of inversion and one in a general position, reside in octa-hedral or tetra-hedral environments, respectively. K⋯O and K⋯N inter-actions occur in the 2.7877 (19)-2.8598 (15) Å range.Acta Crystallographica Section E Structure Reports Online 01/2010; 66(Pt 8):i61-i62. · 0.35 Impact Factor
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ABSTRACT: This perspective focuses on complexes of radioactive metal ions applied in multimodal radio- and optical imaging. The application of metal ions in radioimaging techniques such as Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) has advantages over lighter nuclei in terms of half-life, but there are particular issues related to their speciation (particularly leaching from complexes) and with the combination of certain ions with fluorescent systems. The basic coordination chemistry of the ions involved and issues relating to biological conditions and their compatibility with optical imaging techniques are reviewed, the current literature presented in context, and the prospect of exploiting the intrinsic luminescence of certain metal-ligand complexes is discussed.Dalton Transactions 01/2011; 40(23):6129-43. · 4.10 Impact Factor