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An Open‐Shell Coronoid with Hybrid Chichibabin–Schlenk Conjugation.
Autorzy
Rok wydania
2021
Czasopismo
Angewandte Chemie - International Edition
Numer woluminu
60
Strony
22496-22504
DOI
10.1002/anie.202109273
Kolekcja
Język
Angielski
Typ publikacji
Artykuł
A hexaradicaloid molecule with alternating Kekulé and non-Kekulé connectivities between adjacent spin centers was obtained by fusing two classic conjugation motifs, found respectively in the Chichibabin and Schlenk hydrocarbons, into a coronoid structure. 1 H NMR, ESR and SQUID experiments, combined with computational analyses reveal that the system has a singlet ground state, characterized by a significant hexaradicaloid character ( γ 0 = 0.826, γ 1 = γ 2 = 0.773). It possesses multiple thermally accessible high-spin states (up to the septet), with uniform energy gaps of ca 1.0 kcal/mol between consecutive multiplicities. In line with its open-shell character, the coronoid has a small electronic bandgap of ca. 0.8 eV and undergoes two consecutive one-electron oxidations at low potentials, yielding cationic forms with extended near-infrared absorption. The hexaradicaloid, which combines open-shell and macrocyclic contributions to its π conjugation, provides an example of a design strategy for multistate spin switches and redox-amphoteric NIR dyes.
Adres publiczny
http://dx.doi.org/10.1002/anie.202109273