Research Interests

Photochemical reactions generate radical pairs in a special, spin-correlated quantum mechanical stat that can persist for long enough for weak magnetic fields to have a significant influence on the outcome of the reaction. Research in the Jarocha lab is focused on understanding how these quantum interactions can be leveraged to allow radical pairs to be used as molecular magnetosensors, with potential application to device design, computing, quantum biology, and organic spintronics.

Magnetic field effects on Radical Reactions in Supramolecular and Interfacial Environments

Magnetoreception is a biological sense employed by migratory birds to navigate on a global scale. One hypothesis for the mechanism of this sense involves quantum interactions between the spins of photochemically generated radicals, which allow the radical pairs to act as a molecular compass. While research is ongoing, it has been proven that Cryptochromes, a protein found in the avian retina, can act as a sensor of external magnetic fields. Rather than focus on studies of proteins themselves, our goal is to understand the fundamental principles and properties of molecules and their environments that allow them to act as efficient quantum sensors. We investigate organic molecules incorporated into polymeric and surfactant based supramolecular structures like micelles, vesicles, and bilayers. Altering the size, shape, or physical properties of those structures allows us to influence the quantum interactions of the radical pair. We are particularly interest in how interfacial environments affect the structural, dynamic, and kinetic properties of radical reactions, with the idea that this understanding could be used to maximize the efficiency of chemical sensing of magnetic fields.

Instrument Development for the detection of Magnetic Field Effects

A major critique of the radical pair mechanism of avian magnetoreception is that the protein believed to be responsible, Cryptochrome, has not demonstrated compass behavior in any in vitro measurements. This is may not the fault of the protein per se, but instead may be a consequence of experimental design. One aspect of research in the Jarocha lab is to develop novel instrumentation that is compatible with biomolecules and capable of detecting direction-dependent MFEs on radical pairs that are incorporated in or associated with supported lipid bilayers and other types of interfaces.

Motivation

If we can truly understand how to control quantum processes occurring in molecules and tune those interactions, those principles can be used inform the design and efficiency of devices that rely on spin, including OLDEs, organic photovoltaics, and navigational devices as alternatives to satellite-based global positioning systems.

This research is truly interdisciplinary – sitting at the intersection of chemistry, physics, biology, and materials science. Students in the lab develop skills in magnetic resonance, optical spectroscopy, fluorimetry, instrument development, programming, sample preparation, chemical purification, and characterization of polymeric and surfactant materials.

Publications

• van den Bergh, W.; Wechsler, S.; Lokupitiya, H. N.; Jarocha, L.; Kim, K.; Chapman, J.; Kweon, K. E.; Wood, B. C.; Heald, S.; Stefik, M., Amorphization of Pseudocapacitive T-Nb2O5 Accelerates Lithium Diffusivity as Revealed Using Tunable Isomorphic Architectures. Batteries & Supercaps (early access).
• Xu, J. J.; Jarocha, L. E.; Zollitsch, T.; Konowalczyk, M.; Henbest, K. B.; Richert, S.; Golesworthy, M. J.; Schmidt, J.; Dejean, V.; Sowood, D. J. C.; Bassetto, M.; Luo, J. T.; Walton, J. R.; Fleming, J.; Wei, Y. J.; Pitcher, T. L.; Moise, G.; Herrmann, M.; Yin, H.; Wu, H. J.; Bartolke, R.; Kasehagen, S. J.; Horst, S.; Dautaj, G.; Murton, P. D. F.; Gehrckens, A. S.; Chelliah, Y.; Takahashi, J. S.; Koch, K. W.; Weber, S.; Solov'yov, I. A.; Xie, C.; Mackenzie, S. R.; Timmel, C. R.; Mouritsen, H.; Hore, P. J., Magnetic sensitivity of cryptochrome 4 from a migratory songbird. Nature 2021, 594 (7864), 535-540.
• Zoltowski, B.D.; Chelliah, Y.; Wickramaratne, A.; Jarocha, L.E.; Karki, N.; Xu, W.; Mouritsen, H.; Hore, P.J.; Hibbs, R.E.; Green, C.B.; Takahashi, J.S.Chemical and Structural Analysis of a Photoactive Vertebrate Cryptochrome from Pigeon. Proc. Natl. Acad. Sci. U.S.A., 2019, 116 (39), 19449-19457.
• Bialas, C.; Barnard, D.T.; Auman, D.B.; McBride, R.A.; Jarocha, L.E.; Hore, P.J.; Dutton, P.L.; Stanley R.J.; Moser, C.C. Ultrafast Flavin/Tryptophan Radical Pair Kinetics in a Magnetically Sensitive Artificial Protein. Phys. Chem. Chem. Phys., 2018, 21(25), 13453-13461.
• Zollitsch, T.M; Jarocha, L.E.; Bialas, C.; Henbest, K.B; Kodali, G.,; Dutton, P.L.; Moser, C.C.; Timmel, C.R.; Hore, P.J.; Mackenzie, S.R. Magnetically Sensistive Radical Photochemistry of Non-natural Flavoproteins. J. Am. Chem. Soc., 2018, 140 (28), 8705-8713.
• Bialas, C.; Jarocha, L.E.; Henbest, K; Zolltisch, T.M.; Kodali, G.; Dutton, P.L.; Moser, C.; Timmel, C.R.; Mackenzie, S.R.; Hore, P.J. Engineering an Artificial Flavo-Protein Magnetosensor. JACS, 2016, 138(51), 16584-16587.
• Tarasov, V. F.; Jarocha, L. E.; Avdievich, N. I.; Forbes, M. D. E., TREPR spectra of micelle-confined spin correlated radical pairs: I. Molecular motion and simulations. Photochem. Photobiol. Sci. 2014, 13 (2), 439-453.
• Tarasov, V. F.; Jarocha, L. E.; Forbes, M. D. E., TREPR spectra of micelle-confined spin correlated radical pairs: II. Spectral decomposition and asymmetric line shapes. Photochem. Photobiol. Sci. 2014, 13 (2), 454-463.
• Cabrera-Rivera, F. A.; Escalante, J.; Morales-Rojas, H.; Zigler, D. F.; Schmidt, R. D.; Jarocha, L. E.; Forbes, M. D. E., Photophysical properties of 2,3-dihydroquinazolin-4(1H)-one derivatives. Journal of Photochemistry and Photobiology a-Chemistry 2014, 294, 31-37.
• Zigler, D. F.; Ding, E. C.; Jarocha, L. E.; Khatmullin, R. R.; DiPasquale, V. M.; Sykes, R. B.; Tarasov, V. F.; Forbes, M. D. E., Kinetic analysis of nitroxide radical formation under oxygenated photolysis: toward quantitative singlet oxygen topology. Photochem. Photobiol. Sci. 2014, 13 (12), 1804-1811.
• Forbes, M. D. E.; Jarocha, L. E.; Sim, S.; Tarasov, V. F., Time-Resolved Electron Paramagnetic Resonance Spectroscopy: History, Technique, and Application to Supramolecular and Macromolecular Chemistry. In Advances in Physical Organic Chemistry, Vol 47, Williams, I. H.; Williams, N. H., Eds. 2013; Vol. 47, pp 1-83.
• Caregnato, P.; Jarocha, L. E.; Esinhart, H. S.; Lebedeva, N. V.; Tarasov, V. F.; Forbes, M. D. E., Electrostatic Control of Spin Exchange Between Mobile Spin-Correlated Radical Pairs Created in Micellar Solutions. Langmuir 2011, 27 (9), 5304-5309.

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