Researcher ORCID Identifier


Graduation Year


Document Type

Open Access Senior Thesis

Degree Name

Bachelor of Arts



Reader 1

Nancy Williams

Reader 2

Bethany Caulkins

Reader 3

Natalia Powers-Riggs

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© 2022 Mairead R. Brownell


Ir2(dimen)42+ (dimen = 1,8-diisocyanomenthane) has been studied extensively as model compound to better understand catalysis of photochemical reactions. Although Ir2(dimen)42+ has been used primarily to observe the photophysical changes of metal-metal transitions, it gives great insight into the transitions that allow other d8-d8 metal complexes to undergo photochemical processes and generate hydrogen gas. The large visible range by which Ir2(dimen)42+ (1) can be electronically excited in solution is indicative of its two solution phase ground states, which interestingly have been hypothesized to resemble two unique packing structures observed in the powder state. In this study, the powder diffraction patterns of [Ir2(dimen)4][Cl]2 (1-Cl), [Ir2(dimen)4][PF6]2 (1-PF6), and [Ir2(dimen)4][BPh4]2 (1-BPh4) powders were investigated via X- ray diffraction. The resulting curves were compared to published data and other potential unit cells were generated for the crystalline powder samples. 1-PF6 and 1-BPh4 were determined to have quite different packing structures and symmetries, and while the scattering curve of 1-PF6 matched the previous literature spectrum well, the scattering curve of 1-BPh4 differed quite drastically from the previous literature spectrum. A unit cell could not be determined for any of the species, but a couple of new cells are proposed.