Silicon polyoxolenes: open-shell building blocks for the construction of magnetic or conductive covalent organic frameworks.

Microporous frameworks composed of organic linkers and metal atom nodes (MOFs) or fully covalent networks (COFs) are considered as functional materials of the future. However, to fulfill such promises, they must be equipped with function. The field of conductive or magnetic frameworks is an especially intriguing and highly active research area. Whereas conductivity and magnetism within MOFs have already been tackled by the application of redox-active linkers, analogue strategies in COFs are unexplored – due to the lack of building blocks. Silicon-catecholate based covalent organic frameworks at one side and silicon-catecholate based redox-active complexes on the other, emerged only recently, quasi simultaneously. The same road that was leading to electroactive MOFs can now be explored with SiCOFs. This work aims to study silicon polyoxolenes as suitable open-shell building blocks for the construction of magnetic or conductive SiCOFs, enabling their synthesis by reticular design. A systematic “bottom-up” approach will disclose the magnetic properties within the monomeric building-blocks first, followed by the subsequent investigation of the di- and trimeric diradicals connected through conjugated polytopic linkers. At the same time, an ad hoc synthesis of extended networks, starting from commercial precursors, will be followed. The collaboration between the Greb group (molecular silicon chemistry) and the Powell group (magnetism and MOFs) ideally merges their strengths within both fields of research. The understanding of electron-exchange within metal-free silicon polyoxolenes is not only very satisfying from a fundamental perspective, but such COFs would as well stand for a major step toward an ecologically and economically benign alternative for this future type of functional materials – based on the most abundant elements in the earth crust.