This research looks to investigate environmental and substituent effects on nitrogen-donor-SO3 complexes utilizing a combination of theory and experiment, including quantum chemistry calculations and low temperature matrix-isolation and spectroscopy. The first step is to explore various computational methods and basis sets to provide structural information that is compared to experimental data. For CH3CN-SO3, we have identified a few reliable theoretical methods through an extensive validation study based on predicting the experimental structure and vibrational frequencies of SO3 using a wide range of available computational methodologies. Using these, we have determined the eclipsed confirmation to have a larger binding energy, shorter N-S bond length, compared to the staggered confirmation, and it lacks imaginary frequencies. In addition to minimum-energy structures, we have also obtained information on vibrational frequencies, binding energy, and bond length in various dielectric media for CH3CN-SO3 and mapped potential curves along the N-S bond lengths. We will continue to collect information on binding energies across methods and basis sets to verify which perform the best to be used for future compounds such as ClCH3CN-SO3 and FCH3CN-SO3 and eventually compare our computations to experimental data from our laboratory.
