Double Protonation of 1,5-Bis(triarylaminoethynyl)anthraquinone To Form a Paramagnetic Pentacyclic Dipyrylium Salt

Abstract

Protonation-induced intramolecular cyclization reactions of new donor (D)-acceptor (A) and D-A-D conjugated molecules 1-triarylaminoethynylanthraquinone (1-AmAq) and 1,5-bis(triarylaminoethynyl)anthraquinone (1,5-Am(2)Aq), respectively, were achieved. The former undergoes monoprotonation with bis(trifluoromethanesulfone)imide acid (TFSIH) to give pyrylium salt [1-AmPyl]TFSI, whereas the latter undergoes a novel double proton cyclization reaction to yield 1,5-bis(triarylamino)dipyrylium salt [1,5-Am(2)Pyl(2)](TFSI)(2) with a new pentacyclic backbone. This divalent cationic salt can be reduced to give the neutral species 2,8-bis(triarylamino)benzo[de]isochromeno[1,8-gh]chromene ([1,5-Am(2)Pyl(2)](0)), which maintains the planar pentacyclic backbone. The obtained condensed-ring compounds show unique optical, electrochemical, and magnetic properties due to the extremely narrow HOMO-LUMO gap. In particular, the dication [1,5-Am(2)Pyl(2)](2+) shows paramagnetic behavior with two spins centered on two triarylamine moieties through valence tautomerization with the pentacyclic backbone.

Elaborately Tuning Intramolecular Electron Transfer Through Varying Oligoacene Linkers in the Bis(diarylamino) Systems

“…3, the crystallographic analysis suggests typical propeller-like arrangements for the three aromatic rings around each nitrogen center with respect to the triarylamine termini. The bond parameters including the C—C and C—N distances and the C—N—C angles, fall in the normal range of the data reported in similar systems4344. In addition, a good coincidence between these data and the corresponding computed values can also be found in the later content.…”

Benzo[e]pyrene Skeleton Dipyrylium Dication with a Strong Donor–Acceptor–Donor Interaction, and Its Two‐Electron Reduced Molecule

“…[10] This result indicated that the majority of molecules in equilibrium between the valence tautomers, as shown in Scheme 2, were present in the diamagnetic form. Therefore, DFT calculations were performed for [1,4-Am 2 Pyl 2 ]…”

Design and Synthesis of Antimicrobial Active (E)‐(3‐(Substituted‐styryl)‐7H‐furo[2,3‐f]chromen‐2‐yl)(phenyl)methanone Derivatives and Their In Silico Molecular Docking Studies

“…Heterocyclic compoundscontaining nitrogen and oxygen atoms play an important role in pharmaceutical, agrochemical, and materials chemistry . Recent years, by utilizing varieties of heterocyclic moieties, a large number of drugs and agrochemical products were reported in the literature.…”

“…Another important aspect is that the lipophilic nature of the chromene derivatives helps to peeve the cell membrane effectively . Additionally, benzopyran derivatives also played imperative performance in organic material chemistry like fluorescent dyes, pigments, synthetic fibers, molecular devices , and electrophotographic.…”