In attempt to help better understand the catalytic ability of ruthenium (Ru) complexes in the Aldehyde Water Shift (AWS), the hydricity of the Ru complex must be determined in aqueous solution. This is quite difficult to accomplish, both experimentally and computationally. Hence, we are exploiting the fact that hydricity is contained within a thermochemical cycle with pK<sub>a</sub> and redox potentials in order to help simplify the process. Our research involves computationally determining redox potentials, in volts (V), of these Ru complexes. We are working with a variety of complexes. Density functional theory (DFT) was used, with multiple levels of theory utilizing three (3) functionals (B3LYP, B3P86, and M11) and two (2) basis sets. Ultimately, the goal is to determine the best level of theory to suit a wide array of applications for which hydricity is a key catalyst property. Our research has discovered that basis set was least important in determining redox potentials among the computational parameters investigated with an average of a 0.07 V difference. Changing functionals made a notable difference of 0.50 V on average in predicted redox potentials. The largest contributor to the accuracy of the calculations was ensuring that the complexes are appropriately solvated with a continuum water model, which had an average impact of 6.14 V between the gas state and SMD-water. (Supported by NSF under the CCI Center for Enabling New Technologies Through Catalysis, CHE-1205189)

Redox potentials of ruthenium complexes to understand catalytic ability in water

251st National Meeting (2016)

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