Constanze N. Neumann
Connie was born in Germany, grew up in Austria and received her chemistry training in the UK and the US. She discovered her interest in chemistry when she took part in the Chemistry Olympiad competition during her time in high school. Her experience of participating in the national-level competitions for several years as well as representing Austria in the International Chemistry Olympiad was instrumental in convincing her to pursue a degree in chemistry.
While completing her MChem at the University of Oxford, she worked on the synthesis of Inthomycin A under the supervision of Timothy Donohoe. For her PhD, Connie joined the group of Tobias Ritter at Harvard, where she worked on the development of new fluorination reactions. During her time in the Ritter lab, Connie also trained as a radiochemist at Massachusetts General Hospital (MGH), wherein she was mentored by Jacob Hooker. She worked on developing methodology for the labeling of aromatic molecules with the radioactive isotope 18F to facilitate the synthesis and development of tracer molecules to be used in positron emission tomography (PET), a non-invasive medical imaging technique. During her time at MGH, Connie was able to prepare a PET probe that was injected into a non-human primate in the course of a PET-MRI study.
While working on the translation of a deoxyfluorination reaction into an 18F labeling technique, she became intrigued by the unexpectedly large substrate scope of the reaction. She was able to establish, through a combination of theoretical and experimental work, that the deoxyfluorination reaction proceeded via an unusual concerted nucleophilic aromatic substitution reaction. Unlike in classical nucleophilic aromatic substitution reactions (SNAr), where rate-determining attack of the nucleophile on an arene substrate to form a Meisenheimer intermediate is followed by the loss of the leaving group in a subsequent step, concerted SNAr reactions (CSNAr) proceed via a single transition state. Concerted nucleophilic attack and leaving group loss minimize the build-up of negative charge accumulated on the arene ring and thus lead to a substantial expansion of the substrate scope (to include nucleophilic aromatic substitution para to hydroxy and amino groups!)
To expand her knowledge of inorganic chemistry, Connie then joined the lab of Mircea Dincă at MIT where she studied the development of MOF- and alloy nanoparticle-based catalysts. In the Dincă group, Connie developed a suite of alloy nanoparticle catalysts for the Guerbet reaction where the catalytically active species is formed in situ from a MOF-encapsulated ruthenium precursor. Ethanol upgrading to the promising biofuel 1-butanol can be achieved with >99% selectivity due to the extremely low reactivity of MOF-supported RuNi alloy nanoparticle catalysts towards the reaction product (which is also a potential substrate of the Guerbet reaction).