#  CCB Undergraduates present at 2023 ACS Undergraduate Symposium 

 





August 22, 2023

 

 

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Chem 145 students, students Jack Boettcher and Sajeev Kohli, contributed poster presentations at the 2023 American Chemical Society Undergraduate Symposium between 13-17 August 2023

The two poster abstracts were based on a paper published last year by Jack C. Boettcher, Christie Hung, Sajeev Kohli, Daniel S. Engebretson**,** Daniel R. Morphet, Brandon M. Campbell, Dilek K. Dogutan**,** and Daniel G. Nocera**:** [Probing the Halide Effect in the δ-Bond with One- and Two-Photon Spectroscopy ( (doi.org/10.1021/acs.jpclett.2c01884)](https://pubs.acs.org/doi/10.1021/acs.jpclett.2c01884).

Titles, abstracts, poster PDFs, and pictures below:

Sajeev Kohli

Poster Title: Characterization of Energetic Transition States of Quadruply Bonded Metal Halide Complexes

[Poster PDF](/sites/g/files/omnuum7776/files/chemistry/files/acs_poster-sajeev-ddk.pdf?m=1692726731)

Abstract 1 - Examining Covalency Implications of δ → δ\* Energetic Transitions for Quadruply Bonded Metallic Complexes

Two electrons in two orbitals give rise to four states. When the orbitals are weakly coupled as in the case for the dxy orbitals of quadruple bond species, two of the states are diradical in character with electrons residing in separate orbitals and two of the states are zwitterionic with electrons paired in one orbital or the other. The state energies of the four-state model of the two-electron bond are determined by both one-electron (ΔW) and two-electron (K) energies, but these energies are difficult to distinguish. To this end, synthesis of quadruply bonded species can shed light on these energies. Here, we present the synthesis of the halide series Mo2X4(PMe3)4. Through spectroelectrochemical preparation of their cations, the one-electron energy can be isolated. We find that K energies decrease along the series Cl > Br > I.

 ![jack_and_sajeev_3.jpg](/sites/g/files/omnuum7776/files/chemistry/files/jack_and_sajeev_3.jpg)

 

Jack Boettcher

Poster Title: Synthesizing Quadruply Bonded Metal Halide Complexes for Interrogation of Electron Bond Energies

[Poster PDF](/sites/g/files/omnuum7776/files/chemistry/files/acs-poster-jack.pdf?m=1692726777)

Abstract 2 - Examining Ionicity Implications of δ → δ\* Energetic Transitions for Quadruply Bonded Metallic Complexes

Here, we make use of quadruple bonded metallic complexes of the form Mo2X4(PMe3)4, where X = Cl, Br, and I to interrogate two electron bond energetics. One-photon spectra of Mo2X4(PMe3)4 are sensitive to secondary bonding interactions of the δ-orbital manifold with the halide orbitals, as reflected in decreasing energies along the series Cl > Br > I. Calculated one-electron energies have been verified with the spectroelectrochemical preparation of the Mo2X4(PMe3)4+ complexes, where the δ bond is a one-electron bond. The δ → δ\* transition shifts over 10,000 cm-1 upon oxidation of Mo2X4(PMe3)4 to Mo2X4(PMe3)4+, establishing that transitions within the two-electron δ bond are heavily governed by the two-electron exchange energy.

 ![jack_and_sajeev_4.jpg](/sites/g/files/omnuum7776/files/chemistry/files/jack_and_sajeev_4.jpg)

 



 

 

 



 

 See also:- [ Nocera ](/news-and-events-faculty/nocera)
- [ Undergraduate ](/news-type/undergraduate)
- [ Research ](/news-event-type/research)
 
 

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