Low-spin to low-spin valence tautomeric transition in cobalt bis-dioxolenes†
Abstract
Cobalt dioxolenes are a well-known class of switchable coordination compounds showing intramolecular electron transfer, which is always accompanied by a spin state change at the cobalt center. Here, we present the first example of thermally switchable cobalt bis-dioxolenes where intramolecular electron transfer seems to take place, but the spin state change is suppressed. This leads to the detection of thermal transition between a common ls-CoIII(SQ˙−)(Cat2−) and an extremely rare ls-CoII(SQ˙−)2 electronic state (hs – high-spin, ls – low-spin, SQ˙− – benzosemiquinonate(1−) radical and Cat2− – catecholate(2−)). Parallel to the present work, a similar work but on cobalt mono-dioxolenes has just appeared (Chem. Eur. J., 2023, 29, e202300091), suggesting thermal transition between ls-CoIII(Cat2−) and ls-CoII(SQ˙−) electronic states.
- This article is part of the themed collection: Recent progress and perspectives on spin transition compounds