Chiral covalent organic frameworks for spin-selective processes

In recent times a paradigm shift in chemical reactivity has been induced by the role of chirality.

Indeed, chiral structures have the special electronic property of preferentially transmitting electrons with one spin direction. This phenomenon is called chiral-induced spin selectivity (CISS) effect.

CISS can play a pivotal role in the control of chemical reaction pathways and it has been exploited to improve the selectivity and efficiency of reactions that involve intermediates of different spin multiplicity, like the oxygen reduction reaction (ORR).

Generally, current catalytic systems based on CISS are obtained by anchoring chiral organic molecules to the catalytic units. This approach has some drawbacks, like the reduction of accessibility to the catalytic centers.

To overcome this issue and fully exploit the CISS potential, a new generation of catalysts with intrinsic chirality needs to be designed.

In this context, covalent organic frameworks (COFs), a class of crystalline porous polymers, are highly promising candidates, as they are tunable and designable.

The overall scientific aim of SPIN-COF is to develop new chiral COFs that can exhibit spin-filtering abilities and enhanced catalytic activity.

To this aim, during the outgoing phase at Northwestern University, the synthesis of novel chiral COFs will be investigated. In particular, two families of chiral materials will be produced with different elements of structural chirality.

Then, the CISS properties of the developed materials will be tested during a secondment period at the University of Florence, carrying out magnetic conductive atomic force microscopy measures.

During the return phase at the Max Planck Institute for Solid State Research, the synthesized materials will be tested as catalysts to promote ORR.

The effect of chirality on the catalytic performances will be disclosed, setting new perspectives on the control of chemical reactivity using a new generation of chiral materials.