Jonathan Kephart
@jonkephart3
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Co-chair @Mengshan_Ye and I are sharing a LAST CALL for abstracts to be considered for a talk at the 2025 IRM GRS: We welcome abstracts from diverse fields with clear emphasis on inorganic reaction mechanisms! Submit by 12/2 to be considered for a talk!.
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Graduate students and postdocs — join us for 2025 Inorganic Reaction Mechanisms GRS #IRMGRS scheduled for March 8-9, 2025 in Pomona, CA! Apply early (before 12/1) to be considered as a speaker. See our amazing keynote speaker and discussion leaders:
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RT @nguyen_anh_hao: I’m delighted to share my recent paper in the Journal of Chemical Education. Extremely thankful for the endless support….
pubs.acs.org
Chemistry students at community colleges often experience a lack of hands-on research opportunities, which can be a significant disadvantage when they transition to four-year universities. To address...
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RT @velianlab: Latest from our group now in @ACSCentSci: @jonkephart3 & team uncover that allostery directs reaction chemistry across multi….
pubs.acs.org
Directing groups guide substitution patterns in organic synthetic schemes, but little is known about pathways to control reactivity patterns, such as regioselectivity, in complex inorganic systems...
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9) Subsequently, CNtBu dissociation proceeds with the migration of this strong Fe··Se interaction to the ⍺-oriented Fe site in a "reshuffling" of the frontier electronic orbitals. Indeed, in the solid state, the newly formed Fe-Se bond is markedly contracted.
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8) DFT modeling of intermediates formed along this solvolysis reaction coordinate suggest THF coordination lowers the symmetry of Fe··Se··Co··Se orbitals responsible for the "strong" edge/support interaction, drawing lines of communication between ⍺-oriented Fe centers.
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7) We collaborated with @NathaliaCajiaoS of @TheNeidigLab to conduct 57Fe Mössbauer spectroscopy on bulk solid state samples of these disordered crystals, which also supports the coordination of THF and the formation of a new κ4-bound Fe site.
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6) Interestingly, the amount of free isocyanide observed in the solid state closely matches that detected by solution-phase IR.
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5) Careful inspection of this structure revealed that isocyanide only dissociated from the Fe center positioned on the same face (⍺) of the Co6Se8 core as the newly formed Fe(THF) edge. My labmate Daniel was able to consistently reproduce samples exhibiting this same disorder.
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4) Crystals grown from this solution confirmed the coordination of THF at the previously "naked" Fe center in addition to unusual chemical disorder, wherein CNtBu fully dissociates from one Fe center in the minor component.
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3) Using CNtBu as a vibrational tag, I conducted solution-phase IR spectroscopy with Jason and found that in neat coordinating solvent (THF) the bis(isocyanide) cluster releases a minor amount of free CNtBu.
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2) DFT modeling suggests that oxidation results in the depopulation of a Fe-Se/Co antibonding orbital, which introduces a distinct "strong" edge-support interaction. As a consequence, we obtain these site-differentiated bis-adducts in a stereospecific cis-(⍺,β) conformation.
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1) In early work ( we found that the Fe3Co6Se8 cluster favors site differentiation upon mono-oxidation, with two Fe centers bound by ligands and one tightly bound by the Co6Se8 core. Here, we find that this is the case for a range of monodentate ligands.
pubs.acs.org
Atomically defined interfaces that maximize the density of active sites and harness the electronic metal–support interaction are desirable to facilitate challenging multielectron transformations, but...
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This work provides a framework to understand how ligand/active site/support interactions can orchestrate complex multi-site reactivity, and showcases how edge support covalency can facilitate interadsorbate dynamics between remote active sites dispersed on an inorganic support.
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. @NathaliaCajiaoS and @TheNeidigLab for assistance with 57Fe Mössbauer; Paul from the Chu Group (UW Physics) for assistance with magnetometry; Ryan from the Li Group (UW Chem) for advice with DFT; and last but not least, @velianlab for embarking on this journey with me.
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First, I want to thank all collaborators: Daniel for assisting with the project after I defended; Seb and Werner for extensive crystallography; Jason from the Khalil Group (UW Chem) for assistance with solution IR measurements and fitting analysis. .
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Excited to share more of my graduate research with @velianlab out now in @ACSCentSci! Here, we outline a mechanism for regioselective ligand exchange across multiple active sites on a Fe/Co/Se cluster. 🧵below.
pubs.acs.org
Directing groups guide substitution patterns in organic synthetic schemes, but little is known about pathways to control reactivity patterns, such as regioselectivity, in complex inorganic systems...
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RT @NobelPrize: BREAKING NEWS.The Royal Swedish Academy of Sciences has decided to award the 2023 #NobelPrize in Chemistry to Moungi G. Baw….
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RT @velianlab: Look whom I found at the ACS! Congratulations Dr. @jonkephart3 for the DIC Young Investigator Award!! .
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RT @DehnenStefanie: Last, but not least: the 2023 recipient of the @InorgChem ACS-DIC Lectureship Award, Alexandra Velian @velianlab, givin….
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