What Happens Without Nickel? Cyclization Reactions of Ethylene with Ethanedithial and Related Molecules

We present a computational study of the mechanism of the formation of 6-member heterocycles through the binding of ethylene to oxaldehyde, ethanedithial, and 2-thioxoacetaldehyde. This process is related to the olefin separation technology by metal dithiolenes and dioxolenes, being the formation of those heterocycles the main decomposition route. We also present a benchmark of 26 density functionals (spanning hybrid, double-hybrid, range-separated, semilocal, and local functionals) related to CCSD(T)/CBS reference values. Both the cyclization reaction and the isomerization of the cyclic product are included in the benchmark. The best functional among those tested for these reactions is ?B97XD, and the effect of the basis set is also investigated for it. ? 2017 Wiley Periodicals, Inc. ? 2017 Wiley Periodicals, Inc.This publication was made possible by NPRP grant number 08-426-1-074 from the Qatar National Research Fund (a member of Qatar Foundation)Scopu