Ion-Pairing-Modulated Diradical Properties in Partially Conjugated Negatively Charged π-Electronic Systems.

ABSTRACT: A quinonoidal dipyrrolyldiketone catecholate-boron complex, with two pyrrole-quinonemethide moieties bridged by a six-membered cross-conjugated unit, was synthesized to modulate the diradical character of the dianion formed upon deprotonation. The dianionic species exhibited near-infrared absorption and electron spin resonance (ESR) signals, confirming the diradical properties. Variable-temperature (VT) ESR spectra suggest the thermal excitation from the ground-state singlet diradical to the triplet diradical, providing singlet-triplet energy gaps modulated by coexisting cations and bridging boron moieties.

SUBMITTER: Kobayashi H 

PROVIDER: S-EPMC12642387 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature