From local to global or semilocal aromaticity: singlet–triplet switching in porphyrin tapes

Abstract

Magnetic and electronic analyses of porphyrin tapes uncover a transition from local aromaticity in the ground state to extended/semilocal aromaticity in the triplet state. This reorganization reduces the singlet–triplet gap, establishing porphyrin tapes as aromatic chameleons with state-dependent electronic structures and magnetic responses.