Outer-Sphere Charge-Transfer Excitation in the Ion Pair [Co(NH3)6]3+[B12H12]2-

2001 ◽  
Vol 66 (1) ◽  
pp. 119-124 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Charge Transfer ◽  
Outer Sphere ◽  
Ion Pair ◽  
Uv Absorption ◽  
Charge Transfer Excitation

The aqueous ion pair [Co(NH3)6]3+[B12H12]2- displays an UV absorption at λmax = 250 nm which is assigned to an outer-sphere charge-transfer (OSCT) transition from [B12H12]2- to [Co(NH3)6]3+. OSCT excitation leads to photoredox reaction with the formation of Co2+ (Φ = 0.03 at λirr = 313 nm).

scholarly journals Notizen: Photoredox Reaction of [Hg(cyclam)]2+[Co(CO)4]⁻ Induced by Outer Sphere Charge Transfer Excitation

1993 ◽  
Vol 48 (3) ◽  
pp. 397-398 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Charge Transfer ◽  
Outer Sphere ◽  
Ion Pair ◽  
Metal Charge ◽  
Charge Transfer Excitation ◽  
Metal Charge Transfer

The ion pair [Hg(cyclam)]2+[Co(CO)4]- displays a Co(–I) to Hg(II) metal-to-metal charge transfer (MMCT) band at 288 nm. Upon MMCT excitation the ion pair undergoes a photoconversion to [HgCO2(CO)8].

Notizen: Optical Outer-Sphere Charge Transfer and Photoreactivity of the Ion Pair Tetrabutylammonium Tetrabutylborate

2001 ◽  
Vol 56 (4-5) ◽  
pp. 431-432 ◽  
Author(s):  
Horst Kunkely ◽  
Arnd Vogler
Keyword(s):  
Charge Transfer ◽  
Outer Sphere ◽  
Ion Pair

Abstract The ion pair [N(n-butyl)4]+[B(n-butyl)4]- in CCl4 shows a BR4- → NR4+ outer-sphere charge transfer (OSCT) absorption at λ = 306 nm (sh, ε = 420 dm3 M-1 cm-1). OSCT excitation of the ion pair in CH2Cl2 (λirr > 275 nm) leads to a photo­ lysis with ∅ = 1.5 x 10-3 at λirr = 280 nm. Octane is formed as photoproduct.

Ion association and charge-transfer excitation between N-heterocyclic cations and cyanoiron complexes

1979 ◽  
Vol 57 (16) ◽  
pp. 2079-2084 ◽  
Author(s):  
Henrique E. Toma
Keyword(s):  
Charge Transfer ◽  
Equilibrium Constants ◽  
Ion Association ◽  
Outer Sphere ◽  
Binding Properties ◽  
Donor And Acceptor ◽  
Charge Transfer Excitation ◽  
Optical Charge ◽  
Heterocyclic Cations ◽  
Outer Sphere Complexes

N-Heterocyclic cations form with substituted pentacyanoferrates a series of outer-sphere complexes of general formula Fe(CN)5L//N-Het, suitable for systematic studies in aqueous solution. The equilibrium constants for the association of dipositive cations (e.g. N,N′-dimethyl-4,4-bipyridyl, or paraquat ion) and monopositive cations (e.g. N-methylpyrazinium) with the hexacyanoferrate(II) anion are typically in the range of 30–40 M−1and 10–13 M−1. The optical charge-transfer energies depend on the nature of the N-heterocyclic acceptor, and on the binding properties of the ligand L as they modify the ionization potentials of the Fe(CN)5Ln− complexes. A linear correlation between the optical charge-transfer energies and ΔE0 was found, with a slope (ΔEop/ΔG0) of 1.03 ± 0.03. The results were interpreted on the light of Hush's theory for intervalence transitions, with the aid of the equation Eop = 2(ΔG11* + ΔG22*) + ΔG120, which correlates the optical energy (Eop) for electron-transfer with the intrinsic barriers (ΔG11* + ΔG22*) of the donor and acceptor ions, and the free energy change (ΔG120) for the process.

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