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CBES: Center for Bio-Inspired Energy Science

Danna Freedman

  • Assistant Professor of Chemistry
PhD (2009), University of California, Berkeley

The interaction between a magnetic field and an individual magnetic unit is controlled through two distinct parameters: the size of the magnetic moment and the anisotropy of that moment. Using discrete molecules, Freedman can increase the net size of the magnetic moment, thereby tuning the response of a molecule to a magnetic field. One can envision tethering molecules, each bearing a different spin state, ranging from mononuclear molecules such as the S = 5/2 species to nanoscale multinuclear species with spins up to S = 60. Within this range, motion can be controlled at different levels, with simple chemical linkers such as carboxylic acids or amides connecting each magnetic molecule to a polymer. By tuning the magnitude of spin on each molecule, Freedman can create complex motions with different quantities of magnetic energy inherent in their response. The polynuclear molecule species can be considered atomically precise nanoparticles, thereby enabling precise control over their magnetic properties, with each discrete spin state accessible through synthetic chemistry. 

The force exerted by a magnetic field on the molecules described above can be tuned by the magnitude of the spin. The orientation of this response is manipulated by engendering anisotropy within the molecules, and these internal fields may be tuned through ligand field considerations. 

Key Publications

A Porous Array of Clock Qubits
Zadrozny, J.; Gallagher, A.; Harris, T.D.; Freedman, D.
J. Am. Chem. Soc.2017, 139, 7089–7094.

Millisecond Coherence Time in a Tunable Molecular Electronic Spin Qubit
Zadrozny, J.; Niklas, J.; Poluektov, O.; Freedman, D.
ACS Cent. Sci.2015, 1, 488–492.