Single-component CT Crystals Based on 1,4-Benzoquinone Derivatives and TEMPO Radical

Abstract

Four kinds of TEMPO-substituted 1,4-benzoquinone derivatives were found to afford single-component CT crystals formed by the interactions between a benzoquinone ring and one or two TEMPO groups of the neighboring molecules.

Triptycene 1,2-Quinones and Quinols: Permeable Crystalline Redox-Active Molecular Solids

“…Quinones and hydroquinones (known historically as quinols) play a uniquely important role in chemistry, in part because of their widespread occurrence in nature and their characteristic ability to engage in redox reactions. , In addition, these compounds take part in diverse intermolecular interactions and thereby show strongly associative behavior, allowing them to serve as useful modules in the programmed construction of ordered molecular materials . In particular, the participation of these compounds in charge-transfer interactions and π-stacking has been used to produce assemblies with radicals , and with aromatic compounds. − Quinones and quinols can also form hydrogen-bonded networks with a variety of partners, including heterocycles, , phenols, ,− and other classes of compounds. − The first example of the phenomenon of cocrystallization, reported by Wöhler in 1844, was produced by combining 1,4-benzoquinone and 1,4-hydroquinone in a 1:1 ratio. The resulting structure, known as quinhydrone, features an open network held together by a combination of hydrogen bonds and charge-transfer interactions. − …”

“…1,2 In addition, these compounds take part in diverse intermolecular interactions and thereby show strongly associative behavior, allowing them to serve as useful modules in the programmed construction of ordered molecular materials. 3 In particular, the participation of these compounds in charge-transfer interactions and π-stacking has been used to produce assemblies with radicals 4,5 and with aromatic compounds. 6−8 Quinones and quinols can also form hydrogen-bonded networks with a variety of partners, including heterocycles, 7,9 phenols, 8,10−14 and other classes of compounds.…”

Spin-Carrying Benzoquinone Derivatives

“…However, all of them are usual CT complexes composed of two components of a donor and an acceptor. In this paper, we wish to report the preparation of several 1,4-benzoquinone derivatives carrying TEMPO radical at one or two positions and serendipitous formations of single-component (unimolecular) CT complexes in some of them together with their structures and magnetic properties …”