Oxorhenium Complexes for Catalytic Hydrosilylation and Hydrolytic Hydrogen Production: A Multiweek Advanced Laboratory Experiment for Undergraduate Students

Abstract

An effective way of teaching undergraduates a full complement of research skills is through a multiweek advanced laboratory experiment. Here we outline a comprehensive set of experiments adapted from current primary literature focusing on organic and inorganic synthesis, catalysis, reactivity, and reaction kinetics. The catalyst, bis(2-(2′-hydroxyphenyl)-2-oxazoline)oxorhenium(V) tetrapentafluorophenylborate (1) is isolated through a multistep reaction starting with the formation of the ligand, 2-(2′-hydroxyphenyl)-2-oxazoline (2), followed by complexation of a Re–oxo precursor to form chlorobis(2-(2′-hydroxyphenyl)-2-oxazoline)oxorhenium(V) (3). Both Re(V)–oxo complexes are diamagnetic and allow for NMR analysis. Complex 1 is an air-stable and highly active catalyst for two reactions: (1) hydrosilylation of carbonyls and (2) hydrolysis of Et3SiH to form Et3SiOH and H2 gas. Students monitor the evolution of hydrogen gas in the second reaction and use the data to investigate the reaction kinetics in order ...