A Stable Nitrogen‐centered Bis(imino)perylene Dimer‐based Diradicaloid

Abstract

AbstractCarbon‐centered radicals are usually reactive and there are only few stable heteroatom‐centered organic radicals. Herein, we report a nitrogen‐centered bis(imino)perylene dimer based diradicaloid 2Per‐2 N, which has a large diradical character (y0=72%) but still shows reasonable stability due to kinetic blocking of the aminyl radical sites by the bulky and electron‐deficient 2,4,6‐trichlorophenyl groups and effective spin delocalization. It displays thermally populated paramagnetic activity with a moderate singlet‐triplet energy gap (ΔES–T=−3.55 kcal/mol). Compared with a fully fused bis(imino)quaterrylene analogue (QR‐2 N) which is a typical closed‐shell compound, 2Per‐2 N possesses a much larger diradical character mainly due to the steric repulsion between the neighboring perylene units in the rigid quinoidal form. 2Per‐2 N exhibits a much smaller energy gap and longer absorption wavelength compared with QR‐2 N. 2Per‐2 N represents a rare example of stable nitrogen‐centered diradicaloid with a large diradical character.