Non-bonded interactions between proximate phenyl and polyflourophenyl rings? the regiospecific synthesis of the facial tetrafluorojanusene

Janusene as a silver ion scavenger: insights from computation

“…Such proximity between these aromatic portions enables janusene to exhibit peculiar electronic properties, which have been evidenced from both experimental and theoretical perspectives. 15,[17][18][19][20][21][22] Experiments have shown that the reactivity of the janusene is critically influenced by the proximity of the facial rings. Regarding electrophilic aromatic substitutions, they occur preferentially on the beta carbons of the facial rings, F b , 15,19 due to transannular interactions that destabilize the ground state (GS) through p-repulsion and stabilize the transition state (TS) through p-delocalization.…”

“…15 Preference for facial substitution has also been observed in the formation of the tropylium analogues of janusene, in which substitutions are more prevalent in the facial than in lateral rings, 20 and also in the formation of tetrafluoro-janusene, where the proximity of the phenyl (C 6 H 4 ) and tetrafluoro-phenyl (C 6 F 4 ) rings generates attractive p-p transannular interactions that form the facial substituted product in a regiospecific manner. 21 The 1 H NMR and UV-vis spectra have been proved to be crucial in elucidating the electronic properties of janusene and its derivatives, including charge transfer between the p electron-rich and electron-poor cofacial rings, as well as shielding and deshielding effects depending on the nature of the cofacial rings or the substituents employed in these aromatic moieties. 20,21 Based on the evidence of the presence of p-p transannular interactions in the janusene framework, a recent study has been published by our group, which assessed the interplay between cation-p and p-p interactions by allowing a silver cation (Ag + ) to interact with the different aromatic portions of janusene, in conjunction with the presence of both EDG electron donating and EWG electron withdrawing groups.…”

“…21 The 1 H NMR and UV-vis spectra have been proved to be crucial in elucidating the electronic properties of janusene and its derivatives, including charge transfer between the p electron-rich and electron-poor cofacial rings, as well as shielding and deshielding effects depending on the nature of the cofacial rings or the substituents employed in these aromatic moieties. 20,21 Based on the evidence of the presence of p-p transannular interactions in the janusene framework, a recent study has been published by our group, which assessed the interplay between cation-p and p-p interactions by allowing a silver cation (Ag + ) to interact with the different aromatic portions of janusene, in conjunction with the presence of both EDG electron donating and EWG electron withdrawing groups. 18 Among the eight possible coordination sites, previously observed, 18 six have converged to a minimum of energy, according to Fig.…”