A simple triangular multi-redox pseudo-[6]oxocarbon capable of accepting up to six electrons

11 July 2023, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


Multi-electron redox chemistry is traditionally a domain of transition metals which are well-known to show multiple valence states with a vast variation of physical and chemical properties. Redox-active organic molecules, on the other hand, usually present only two valence states. Herein we demonstrate the design and preparation of a very simple organic molecule benzo[1,2-c:3,4-c':5,6-c'']tris([1,2,5]thiadiazole) 2,2,5,5,8,8-hexaoxide (tripak) that shows unprecedently rich redox chemistry and is capable of accepting up to six electrons in five consecutive reduction steps. Tripak is a derivative of the thermodynamically unstable [6]oxocarbon C6O6, where all C=O groups were used to form three dioxothiadiazole rings. It is the first representative of the new poly(dioxothiadiazole) family of compounds comprising three dioxothiadiazole groups fused together to form a simple rigid highly symmetrical skeleton with a single benzenoid ring in the middle. The electron withdrawing character of the dioxothiadiazole rings is responsible for the reversible multi-electron redox behavior which enabled its isolation and complete structural and physicochemical characterization in five-out-of-six oxidation states: 0, -1, -2, -3 and -4. Depending on the number of electrons, the tripak system represents different types of aromaticity (non-aromatic, Hückel or Baird) and redox-related multifunctionality: tripak0 shows record-strong anion-π binding of halides which is comparable with the energy of coordination bonds, tripak1- and tripak3- are two very different S = 1/2 radical states with tripak1- exhibiting very long spin-spin relaxation time at room temperature placing it among the most promising molecular qubit candidates, tripak2- is a blue dye with strong red fluorescence and finally tripak4- is an open-shell singlet diradicaloid system with a singlet-triplet gap close to zero.


strongest anion-pi

Supplementary materials

Supporting Information
Supporting Information for preprint "A simple triangular multi-redox pseudo-[6]oxocarbon capable of accepting up to six electrons"


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.