Motivation, Research & Group Life
We are a synthetic group interested in inorganic and coordination chemistry, energy conversion and organic materials. We focus on methodology and mechanisms including the isolation of reactive intermediates, their bond-activation chemistry (targeting eventually catalysis), and their spectroscopic properties. We use computational chemistry to guide our synthetic efforts. We are passionate about any type of inorganic and organic chemistry, because we believe that all elements are made equal. Typically, our research involves carbenes and molecules with small frontier orbital energy gaps such as radicals, diradicals and zwitterions. We aim at creative and innovative approaches for long-standing challenges.
We have proposed that charge-separation, viz. zwitterionic character, in π-systems is a general motif for molecules which activate strong bonds, are " smart", photoactive, and stimuli responsive. Indeed, some multiple bonded late transition metal compounds "beyond the oxo-wall", in our case a formally terminal imido complex, can be understood as vicinal zwitterions. This peculiar electronic structure allows for the swift activation of strong bonds in redox catalysis. En route to such zwitterions, we have developed new synthetic methodology using organometallic iron- and cobalt complexes
We have proposed and demonstrated how to tame diradicals using carbenes for application in singlet-fission, alleged technology of future solar cells with unrivaled quantum efficience, and two-photon absorption, key for biomedical imaging and signal transmission. Current work is dedicated to both areas as well as rendering organic radicals, commonly highly air-sensitive, sufficiently stable for practical applications. In a side project, we have discovered bright luminescent complexes of s-block (!) metals.
We have a long-standing interest in the mechanistic intricacies of late transition metal catalysis. Using a large variety of physical-organic and physical-inorganic techniques, we have shown how Pd(0) complexes may oxidatively add amines, alcohols, CC bonds, and water, previously though to be unfeasible. Our findings suggest how to achieve additive-free and thus "green" cross-coupling catalysis. Current research is directed at catalytic applications and the exploitation of ligand-metal cooperativity.
We have highlighted in a "review of reviews", how the tunability of carbenes allows to specfically tailor the electronic properties of transition metal complexes. Accordingly, we proposed how to tailor the electronic properties of organic materials by use of carbenes as "organic functional groups". In subsequent work, we have shown which effects make organic radicals (key for organic electronics) either persistent or disproportionate. Current efforts are targeting switchable materials.
We have been involved in the computational analysis of various molecules with intriguing electronic properties. This includes, among others, homoleptic "chiral" uranium complexes, open-shell alkyne complexes of the 3d metals, molybdenum and tungsten silylidynes and their dimers, P4 activation by silyl stannylenes, molybdenum imido complexes, and iron cyclopentadienyl complexes in unusual oxidation states.