The coronavirus pandemic has disrupted higher education in many ways. One significant disruption is a change to online course delivery due to semester-long safety concerns or from shorter emergency changes due to an outbreak of the virus. Our campus was faced with a two week emergency change to online instruction due to an outbreak during the Fall 2020 Semester. Our Advanced Inorganic Lab course was impacted by the temporary change to online course delivery. This presentation describes a research-based, virtual, lab experience that was developed in response to the unexpected change in the course delivery method; a lab experience that could be delivered readily on other campuses if such a need arises. The virtual lab experience is built around current research in our laboratory involving variable temperature 31P-{1H] NMR measurements of pseudorotational rearrangements, hydride ligand exchanges, and isomerizations that occur at eight-coordinate rhenium(V) polyhydride complexes supported by triphenylphosphine ligands. Undergraduate chemistry majors typically encounter the dynamic nature of molecules in organic chemistry. Free rotation about a single carbon-carbon bond or the pseudorotational exchange of axial and equatorial hydrogen atoms of cyclohexane are common examples of molecular dynamism found in introductory organic chemistry courses. Undergraduate inorganic chemistry courses often use the Berry pseudorotation or free rotation about metal-metal triple bonds to introduce the dynamism of inorganic systems. The virtual lab described here affords instructors an opportunity to use readily available real data to provide students with a learning experience focused on practical examples of the application of variable temperature NMR spectroscopy to the determination of appropriate models and activation barriers for the molecular dynamics of some dynamic, dodecahedral, rhenium(V) eight-coordinate, complexes. Pseudorotational rearrangement of the eight-coordinate complexes and facile interconversions between E and Z isomers are the dynamic processes of interest in this laboratory exercise. Available variable temperature 31P-{1H} NMR data provide the observations that allow for the investigation of the dynamic properties of the studied molecules. Estimation of the kinetics for the dynamic processes at various temperatures, through simulation of the experimental data, allows for the estimation of activation parameters for the dynamic processes.

Virtual inorganic lab on isomerization and pseudorotation using variable temperature 31P-{1H} NMR data

ACS Spring Meeting 2021

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