Research in the Swart Lab focuses on the design of density functionals and application of these in transition-metal chemistry, to study the effect of transition metals on reactivity, selectivity, chemical bonding and spectroscopy. Several scientific breakthroughs in the understanding of spin and oxidation states involved have led to multiple scientific projects among which a COST Action. Because of this, he has been approached by many experimental groups to collaborate on spectroscopy and reactivity of (high-valent) transition-metal complexes, their electronic structure and how this is influenced by the metal and type of ligand(s) present. Central in these studies is the use of spin-state consistent density functionals (S12g, SSB-D, OPBE and the upcoming fPBEg and S24g).
Spin states of transition-metal complexes
Molecules with different numbers of unpaired electrons, hence with different spin states, have distinct geometric structures, energetic properties and reactivity.
Elucidating the role and effect of different spin states on the properties of a system is presently one of the most challenging endeavors.
This is in particular true for reaction mechanisms where the spin or oxidation state of a metal can change during the reaction.
Transition-metal reactivity studies
The reaction mechanism of chemical processes with transition-metals often involves a switching from one spin-state to another during the reaction.
Moreover, with transition-metals, a multitude of reaction mechanisms has to be considered.
In collaboration with experimental groups we carry out #CompChem experiments to characterize intermediates and transition structures, to determine the most favorable reaction path.
Lewis acids: stabilization of vulnerable species
Several studies in the literature showed the effect of adding Lewis acids to stabilize volatile transition-metal species, or alternatively increase their reactivity. The effect of the Lewis acids on the stability, reactivity and spectroscopic properties is poorly understood, and is being studied here in collaboration with experimental groups.
Development of computational research tools
New research tools have been developed such as QUILD with improved optimization and transition-search routines, and spin-state consistent density functionals (S12g, SSB-D). The advantage of these tools is that they can be applied straightforwardly also to other systems such as DNA, SN2-reactions, NMR chemical shifts and the like.
