Photochemical reaction of dicyanoanthracene with acetonitrile in the presence of an aliphatic amine. A novel photochemical amination

Spectroscopic characterization of photoaccumulated radical anions: a litmus test to evaluate the efficiency of photoinduced electron transfer (PET) processes

“…In all of the above cases, the generated radical anion (A–Y •− ) is a persistent species easily detected by laser flash photolysis. This approach applies to a variety of donors, including amines [12–13], carboxylic acids or their derivatives [14–15], aliphatic acetals and ketals [16], ethers [17], organostannanes [18–19], organosilanes [20–22], aromatics [10,23–24], and even alkanes [25–27]. BET (path a') could ensue, thus leading to no chemical change.…”

Red Light-Based Dual Photoredox Strategy Resembling the Z-Scheme of Natural Photosynthesis

“… 97 , 102 , 143 − 145 Furthermore, concerning the reactivity and stability of DCA •– , a variety of very different observations were reported in the literature, including claims of reasonably good stability of DCA •– , 146 as well as observations of comparatively rapid degradation reactions with the solvent, reaction intermediates or oxygen. 140 , 147 − 149 Overall, the stability and reactivity of DCA •– seem to be highly dependent on the actual conditions in solution, and it seems that these aspects are sometimes overlooked. In our catalytic system, it seems plausible that DCA •– accumulates over time as a result of [Cu(dap) 2 ]Cl irradiation in the presence of excess DiPEA.…”

“…In summary, the two mechanisms in Figure 6 contribute to different extents in different solvents, and furthermore, other photoactive species related to the copper complex or DCA could contribute to the overall reaction. 147 − 149 One specific possibility not discussed here is for example triplet–triplet annihilation upconversion of 3* DCA •– to yield 1* DCA •– , followed by reduction of the latter with DiPEA. The PET versus TTET competition illustrated in Figure 6 captures however the main essence of the [Cu(dap) 2 ]Cl/DPA dual photoredox system.…”

Sequential two electron photooxidation of t-amines: generation of a regiospecific iminium cation and its application in organic synthesis

“…15 These studies have also provided predictive capabilities for the regioselectivity of unsymmetrical amine photoadditions. In sharp contrast, photoreaction 16 between cyanoarene, a potent electron acceptor, and t-amine in acetonitrile gives the addition product of acetonitrile to cyanoarene instead of amine, possibly due to the involvement of longer lived solvent separated ion pairs (SSIP) in these particular systems. This difference in the reactivity pattern of the excited singlet cyanoarene with t-amines, 16 led us to explore further this fundamental reaction processes.…”

“…In sharp contrast, photoreaction 16 between cyanoarene, a potent electron acceptor, and t-amine in acetonitrile gives the addition product of acetonitrile to cyanoarene instead of amine, possibly due to the involvement of longer lived solvent separated ion pairs (SSIP) in these particular systems. This difference in the reactivity pattern of the excited singlet cyanoarene with t-amines, 16 led us to explore further this fundamental reaction processes. It was argued that the SSIP formed between 1,4-dicyanonaphthalene (DCN) and t-amine after initial one electron exchange, in a solvent of high dielectric constant, would dissociate into free radical ion pair (FRIP) where the cyanoarene anion radical would be potentially less reactive towards the amino cation radical.…”