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Chemistry
Completed Project

Density Functional Theory Study of Methyl Iodide and Its Oxidative Addition to Trinuclear Gold(I) Complexes

OGabrielle Costner ’21, Brandon Lam ’23 and Professor Brooke Michelle Otten (Chemistry)

In recent years the study of the electronic and luminescent properties of trinuclear gold(I) complexes (CTCs) has led to applications in the field of organic light emitting diodes as well as thin film development for anti-corrosion materials. However, possible usage of these CTCs as catalysts has not been fully explored. A well known reaction type for gold(I) centers is oxidative addition, which takes a gold(I) center and converts it to a gold(II) or gold(III) center, depending on the number of electrons transferred. There have been previous experimental studies which have demonstrated that CTCs are capable of undergoing oxidative addition with dihalogens through a stepwise process, leading to mixed valent gold(I)/gold(III) centers. In addition to these experimental studies, there have also been reports of crystal structures with the addition of methyl iodide to gold centers, but there have been no reports or studies on the mechanistic details of these reactions. In this study, we aim to explore the kinetic and thermochemical properties of the oxidative addition of methyl iodide to a CTC. The initial steps of this work focused on determining the best combination of functional and basis set to model the bond length and vibrational frequency of the carbon-iodine bond in methyl iodide. This combination was then used to determine the mechanism of action for the oxidative addition of methyl iodide to the CTC used in the study. Through this study, it was determined that a hybrid density functional and a fully augmented basis set with a pseudopotential on iodine was needed to accurately model the carbon-iodine bond (B3PW91 and aug-cc-pVTZ). Due to the solid state structure of the CTCs, dispersion corrections were added for the modeling of the species involving the CTCs. The energetic and structural results are presented for the benchmarking and mechanistic studies performed for this study.