[9] Arteta, S.; Deegbey, M; Durand, N.; Kibbe, R; Floß, J.; Barth, A. T.; Jakubikova, E; Reiser, O; Muddiman, D.C.; Castellano, F.N.* “Mechanistic insights to visible-light induced ATRA reaction powered by the symbiotic relationship between Cu(II)/Cu(I) phenanthroline-based complexes” (Article ASAP, ACS Catalysis)

Cu(I) platforms are ubiquitous in LMCT photocatalysis, but their utility in photochemical reactions is obfuscated by the influence of paramagnetic Cu(II). We establish a symbiotic photocycle that assigns the role of both oxidation states.

[8] A. T. Barth†, A. J. Pyrch†, C. T. McCormick, E. O. Danilov, F. N. Castellano* “Excited State Bond Homolysis of Vanadium(V) Photocatalysts for Alkoxy Radical Generation”.  J. Phys. Chem. A 2024, 128, 36, 7609–7619.

Vanadium(V) has received recent interest as a base-metal platform to degrade nonbiodegradable plastics. We interrogate the UV-activated intramolecular homolysis as an activation strategy for this desired reactivity.

[7] S. Sridhar, S. Khansari, S. O’Donnell, A. T. Barth, E. O. Danilov, F. N. Castellano, P. A. Maggard, D. B. Dougherty.* “Ligand Field Exciton Annihilation in Bulk CrCl₃” J. Chem. Phys. 2024, 161, 114706.

Chromium(III) molecules have emission originating from ligand-field excited states. In collaboration, we propose a ligand-field assignment for this emission band in solid-state materials.

[6] A. T. Barth†, J. Fajardo Jr.†, W. Sattler, J. R. Winkler,* H. B. Gray,* “Electronic Structures and Photoredox Chemistry of Tungsten (0) Arylisocyanides.” Acc. Chem. Res. 2023, 56, 14, 1978–1989.

A review establishing low-valent tungsten(0) complexes as a new category of earth-abundant 5d photoredox catalysis, reflecting on initial observations on these molecules the Gray lab in the 1970s, and our efforts to repurpose these photostable complexes as photoredox catalysts today.

[5] B. J. McNicholas,* C. Nie.; A. Jose, P. H. Oyala, M. K. Takase, L. M. Henling, A. T. Barth, A. Amaolo, R. G. Hadt, E. I. Solomon, J. R. Winkler, H. B. Gray,* E. Despagnet-Ayoub.* “Boronated Cyanometallates” Inorg. Chem. 2023, 62 (7), 2959–2981.

This work outlines an extensive catalog of electronic structure manipulations that can be introduced through boron interactions with the cyanides of cyanometallate complexes, useful as non-aqueous redox flow batteries.

[4] A. T. Barth, M. Morales, J. R. Winkler,* H. B. Gray,* “Photoredox Catalysis Mediated by Tungsten(0) Arylisocyanides in 1,2-Difluorobenzene” Inorg. Chem. 2022, 61, 19, 7251–7255.

Cage escape yield was a proposed bottleneck in the efficiency of our potent tungsten(0) photocatalysts. This subsequent work explored manipulating solvent polarity as a handle to enhance the photoredox activity and efficiency.

[3] J. Fajardo Jr., A. T. Barth, M. Morales, M. K. Takase, J. R. Winkler,* H. B. Gray,* “Photoredox Catalysis Mediated by Tungsten(0) Arylisocyanides.” J. Am. Chem. Soc. 2021, 143, 46, 19389–19398.

We demonstrate that tungsten(0) photocatalysts can function as potent photoreductant using either UV (400 nm) or two-photon absorption using NIR (800 nm) light. This is a pioneering example of red light-driven photoredox catalysis.

[2] D. X. Ngo, S. A. Del Ciello, A. T. Barth, R. G. Hadt, R. H. Grubbs, H. B. Gray,* B. J. McNicholas,* “Electronic Structures and Electrochemistry of [M(diamine)(CNBR3)4]2- (M = Fe, Ru; R = Ph, C6F5) Complexes.” Inorg. Chem. 2020, 59, 14, 9594–9604.

Boranes act as Lewis acids and can be used to manipulate the electronic structure of cyanometallates. Here, we investigate these influences on di(immine) complexes to interrogate the changes to their photophysical properties.

[1] N. Higdon, A. T. Barth, P. Kozlowski, and R. G. Hadt,* “Spin–Phonon Coupling and Dynamic Zero-Field Splitting Contributions to Spin Conversion Processes in Iron(II) Complexes.” J. Chem. Phys. 2020, 152 (20), 204306.

Molecular motions govern spin-crossover dynamics in pseudo-octahedral Fe(II) complexes. Here, we used CASSCF-NEVPT2 multireference calculations to model the changes to the excited state energy levels along relevant normal modes.