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Solvatochromism and Redox Multi-Switch in a Trinuclear Cobalt(II) Complex
Solène Delaporte1, Nathalie Bridonneau1, François Lambert1
1Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris-Saclay UMR 8182, 17, avenue des Sciences, Orsay, 91400, France.
Abstract:
A trinuclear cobalt(II) complex incorporating the redox-active hexahydroxytriphenylene (H6HHTP) ligand was prepared and isolated in two different redox states: [CoII 3(sq-sq-sq)]3+ (1) and [CoII 3(cat-sq-sq)]2+ (2) (sq = semiquinone; cat = catecholate), enabled by its remarkable solvatochromic behavior. The ligand field tuning of the Co(II) centers through the ancillary ligand Me3TPA (tris(6-methyl-2-pyridylmethyl)amine) allowed accessing six reversible one-electron processes instead of only three with the parent TPA ligand, therefore increasing the range of redox-coupled magnetic and optical switching in this system. Upon reduction, the three redox processes are ligand-centered and involve the three sq•-/cat2- couples of hexahydroxytriphenylene (HHTP), while we hypothesize that some of the oxidation processes may involve the Co(II) metallic species.
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