Author ORCID Identifier

Document Type


Date of Award


Degree Name

Master of Science (MS)



First Advisor

Bess Vlaisavljevich


Sm(II) diiodide is widely used in organic synthesis for the reduction of functional groups such as esters, anhydrides, amides, carbonyls, and arenes. Moreover, in aqueous systems and in mixtures of water and THF, the addition of Sm(II) diiodide can reduce water directly resulting in the formation of hydrogen gas. However, the mechanism of these reactions is not completely understood, making it difficult to improve experimental design. The reaction can proceed either through subsequent electron-transfer proton-transfer (ET-PT), subsequent proton transfer electron-transfer (PT-ET), or via proton coupled electron transfer (PCET). Density functional theory (DFT) calculations were performed to understand the speciation of seven-coordinate Sm(II) and Sm(III) species with varying numbers of iodide, water, and THF ligands. Specifically, the overall thermodynamics of [SmIII2(THF)n(H2O)m] ,[SmIII(THF)n(H2O)m]+, [SmII(THF)n(H2O)m]2+, and [SmIII(THF)n(H2O)m]3+ was explored. The effect of solvent dielectric constant on speciation was also modeled. From the most energetically favorable species, the reduction mechanisms were computed. DFT predicts that in pure THF, the iodide ions remain coordinated but decoordinate in aqueous media. Additionally, a mixture of Sm species are expected to be present in solution but nature of the ligands has only a minor impact on the overall thermodynamics of the reaction to form hydrogen gas which proceeds via PCET.

Subject Categories

Computational Chemistry


Sm(II) diiodide

Number of Pages



University of South Dakota

Available for download on Thursday, August 22, 2024