Metal catalyst-free amination of meso-bromoporphyrins: an entry to supramolecular porphyrinoid frameworks

Quantum-Сhemical Insight into the Reactivity of 5-Bromo-10,20-diaryl-porphyrins towards Nucleophiles

“…In contrast, the set of compounds 2a-g includes the 15-amino-substituted derivatives, which differ in the steric and electronic character. Some of these compounds were already studied in the nucleophilic substitution reaction, namely 1a, 1d and 2a [17,18] while others were chosen for the prediction of the scope of the reaction. In this regards, the amino substituted derivatives are the most interesting substrates due to their donor character and expected low reactivity in the studied reaction.…”

“…It is remarkable, that 1d undergoes nucleophilic substitution reaction with various primary amines with 52-89 % yields. [17] In this respect we expect that all these compounds could react with the nucleophiles.…”

“…It was found that meso-monobromoporphyrins reacted with primary amines affording meso-monoaminoporphyrins with 50-95 % yields. [17,18] Although the electron-withdrawing substituents facilitate the substitution, [18] unactivated meso-mono-and dibromoporphyrins also can be used as substrates for this reaction. [17][18][19] The reaction of porphyrins with O-and S-nucleophiles allows preparation of aryloxy-and arylthiasubstituted porphyrins with up to 70 % yield.…”

“…[17,18] Although the electron-withdrawing substituents facilitate the substitution, [18] unactivated meso-mono-and dibromoporphyrins also can be used as substrates for this reaction. [17][18][19] The reaction of porphyrins with O-and S-nucleophiles allows preparation of aryloxy-and arylthiasubstituted porphyrins with up to 70 % yield. [20][21][22][23] Moreover, meso-functionalization of diarylporphyrins is possible also by the nucleophilic addition of alkyl-or aryllithium reagents to the porphyrins followed by the oxidation of the resulting porphyrinogens.…”

“…Analyzing the limited experimental data, it is possible to speculate that the electronic effects of a substituent at 15 position significantly influence the process. [17,18] Our objective was to find a rapid and reliable method for an estimation of the reactivity of 5-bromoporphyrins towards nucleophiles without carrying out complete DFT calculation of structural and energy characteristics of the reaction paths. We have demonstrated that DFT/6-31G* calculation of frontier orbital localization of the substrate molecule is sufficient for a reliable prediction of the reactivity.…”