Tuning phenoxyl-substituted diketopyrrolopyrroles from quinoidal to biradical ground states through (hetero-)aromatic linkers.

ABSTRACT: Strongly fluorescent halochromic 2,6-di-tert-butyl-phenol-functionalised phenyl-, thienyl- and furyl-substituted diketopyrrolopyrrole (DPP) dyes were deprotonated and oxidised to give either phenylene-linked DPP1˙˙ biradical (y ₀ = 0.75) with a singlet open shell ground state and a thermally populated triplet state (ΔE _ST = 19 meV; 1.8 kJ mol^-1; 0.43 kcal mol^-1) or thienylene/furylene-linked DPP2q and DPP3q compounds with closed shell quinoidal ground states. Accordingly, we identified the aromaticity of the conjugated (hetero-)aromatic bridge to be key for modulating the electronic character of these biradicaloid compounds and achieved a spin crossover from closed shell quinones DPP2q and DPP3q

SUBMITTER: Rausch R 

PROVIDER: S-EPMC8179021 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature