235: Computational investigation of the oxidation and reduction chemistries of the bis(2-(2,3-dioxido)-6-pyridyl-methyl](2-pyridylmethyl)amine diiron(III) complex ion

Abstract: Methane monooxygenase is an enzyme that can turn methane into methanol using metals like iron. Because methanol burns cleaner than conventional energy sources and is a liquid, making it easier to transport, finding an efficient and sustainable route to mimic the process performed by nature is desired. The reported complex, bis-[2-(2,3-dioxido)-6-pyridyl-methyl] (2-pyridylmethyl)amine diiron(III) chloride ([BCATTPAFe2]Cl2), has a similar di-iron structure to the active site in the enzyme and therefore has been of interest in our laboratory. Optimization and frequency calculations were performed on the positive portion of the complex using Gaussian 16 to find the most stable spin state. The six different spin states run were singlet, triplet, quintet, septet, nonet, and undecet in the gas phase and in Dimethyl sulfoxide as a solvent. The initial method used for these calculations consisted of a 6-31G(d) basis set and an unrestricted B3LYP functional. The calculations were also run using Ahlrichs TZ basis set def2-TZVPP with polarization functions and the B3LYP functional with or without an added dispersion correction as well as the MN15 functional. The optimization and frequency calculations were also run on the two-electron reduced and two-electron oxidized forms of the complex using the MN15 functional with the def2-TZVPP basis set. The predicted electronic structures from these calculations are compared.