Proton-coupled charge-transfer reactions and photoacidity of N, N -dimethyl-3-arylpropan-1-ammonium chloride salts

Abstract

Photoinduced intermolecular proton-transfer processes from N,N-dimethyl-3-arylpropan-1-ammonium chloride salts (ArCl, with aryl as 1-pyrenyl, 9-anthryl, and 2-naphtyl) to a solvent molecule have been investigated by steady-state and dynamic spectroscopic methods. The intermolecular proton-transfers are coupled either to the formation of an exciplex or to a solvent-separated ion pair in what we have termed a 'proton-coupled charge-transfer reaction'. A range of solvents has been observed to mediate both the ground-state conformations of the ArCl and the extent of electron transfer. Unlike typical photoacids, in which through-bond interactions control photoacidity, through-space charge-transfer interactions are responsible in the excited singlet states of the ArCl. Transient absorption experiments reveal a range of electronic comportments in the excited-states of the ArCl. Excited-state pK values of -3.4, 1.3, and -3.3 in THF were calculated using a Förster-like approach for the 1-pyrenyl, 9-anthryl, and 2-naphthyl salts, respectively. The observed rate of proton-transfer was found to be independent of the thermodynamic driving force and the short-term reversibility of these reactions has been approximated. The data suggest how other systems may be designed to facilitate this novel process.

Ultrafast Intermolecular Energy Transfer in OLED Materials: Excited-State Dynamics of a Blend of Poly(vinylcarbazole) and Oxadiazole Derivative in Solution and Film States

“…From the slope of the linear plot, the Stern− Volmer quenching constant (K SV ) and k q values were found to be 1.2 × 10 6 M −1 and 8.0 × 10 13 M −1 s −1 , respectively. The k q value is found to be higher than the normal diffusioncontrolled rate constant (1.44 × 10 10 M −1 s −1 ) 37,38 and supports the occurrence of fast FRET 39,40 from the PVK to OXD.…”

“…The k q value is found to be higher than the normal diffusion-controlled rate constant (1.44 × 10 10 M –1 s –1 ) , and supports the occurrence of fast FRET , from the PVK to OXD .…”

Photolysis of Tertiary Amines in the Presence of CO2: The Paths to Formic Acid, α-Amino Acids, and 1,2-Diamines

“…Products were identified by a comparison with authentic samples. See Supporting Information for details. b Oxidation potentials vs SCE. − c Product yields referred to converted amine 1 . …”

Photo-induced Electron Transfer or Proton-Coupled Electron Transfer in Methylbipyridine/Phenol Complexes: A Time-Dependent Density Functional Theory Investigation

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