New reactivity in dehydrogenation reactions: halogen bonding and cooperative ligands

There is an urgent need for switching the world’s energy system, from a fossil based to a renewable one based on e.g., wind-, solar- and hydropower which are clean and fossil free. However, to gain full environmental benefits from these fluctuating renewable sources energy storage is needed. This project seeks to offer Liquid organic hydrogen carriers (LOHCs) as an energy storage material.

LOHCs can reversibly add/release H2. More specifically, we aim at developing novel homogeneous catalyst systems for acceptorless dehydrogenation of LOHCs.

To access previously untapped activity we aim to utilize two innovative approaches to gain increased reactivity: Using second coordination sphere interactions in the form of dynamic halogen bonding (XB) to polarize iridium hydrides and perturb their reactivity.

We have preliminary results that show that XB interactions change the structure of iridium dihydrides and also DFT calculations that indicate a polarization (increased charge separation between the two hydrides) based on the structural change.Using iridium carbene complexes with potentially cooperative reactivity in order to access alternative mechanisms for dehydrogenation.

Iridium carbenes that are immune to beta-elimination will be developed and various ligand designs will be tested to achieve a balanced polarity of the Ir=C bond.The knowledge gained in these investigations will be used to increase activity in dehydrogenation of relevant LOHCs (alcohols, amines and alkanes).