Functionalization of CnH2n+2Alkanes: Supercritical Carbon Dioxide Enhances the Reactivity towards Primary Carbon-Hydrogen Bonds
The functionalization of the primary sites of alkanes is one of the more challenging areas in catalysis. In this context, a novel effect has been discovered that is responsible for an enhancement in the reactivity of the primary C-H bonds of alkanes in a catalytic system. The copper complex Cu(NCMe) (=hydrotris{[3,5-bis(trifluoromethyl)-4-bromo]-pyrazol-1-yl}borate) catalyzes the functionalization of CnH2n+2 with ethyl diazoacetate upon inserting the CHCO2Et unit into C-H bonds. In addition, the selectivity of the reaction toward the primary sites significantly increased relative to that obtained in neat alkane upon using supercritical carbon dioxide as the reaction medium. This was attribu…
Accelerated dinuclear palladium catalyst identification through unsupervised machine learning.
Although machine learning bears enormous potential to accelerate developments in homogeneous catalysis, the frequent need for extensive experimental data can be a bottleneck for implementation. Here, we report an unsupervised machine learning workflow that uses only five experimental data points. It makes use of generalized parameter databases that are complemented with problem-specific in silico data acquisition and clustering. We showcase the power of this strategy for the challenging problem of speciation of palladium (Pd) catalysts, for which a mechanistic rationale is currently lacking. From a total space of 348 ligands, the algorithm predicted, and we experimentally verified, a number…
CCDC 2064863: Experimental Crystal Structure Determination
Related Article: Julian H��ffel, Theresa Sperger, Ignacio Funes-Ardoiz, Jas Ward, Kari Rissanen, Franziska Schoenebeck|2021|Science|374|1134|doi:10.1126/science.abj0999