Electron Spin Selectivity of Chiral Matter, from Molecules and Supramolecular Assemblies to Life
Abstract
The discovery that electron currents and electron displacements in chiral matter are spindependent, chiral-induced spin selectivity (CISS), promises to transform the way we execute chemical reactions, store and transmit information, and understand biological homochirality. Although the discovery of electron spin and its essential importance to the structure of matter was developed in the 20th century, its connection to the chiral symmetry of matter has only become evident in the 21st century. Our collaborative group proposes an integrated research effort to develop and test a quantitative first principles theory for the CISS effect, to develop structure-function relationships and new compositions of chiral matter that enable the effective delivery of spin-filtered electron currents at ambient temperatures, to apply CISS-based concepts in electrocatalysis that enable improved efficiency and selectivity in multi-electron chemistry, and to elucidate how CISS manifests in biology. The research project is organized into three tightly integrated Thrusts. In Thrust 1, entitled Structure-Function relationships for spinselective electron transfer and transport, well-defined molecular and electronic chiral forms of matter are studied with incisive spectroscopic and electrical methods. These new compositions of matter are chosen to allow structural and electronic properties to be systematically tuned and have their spin-selective electron transfer and electron transport properties quantified. Working hand-in-hand with theoretical developments, we will apply cutting-edge experimental probes to CISS phenomena, examine mechanisms for electron spin filtering in chiral matter, and develop chiral materials for the delivery of spin-filtered electron currents. These studies promise to reveal the underlying physics of CISS, to provide a quantitative theory for CISS, and to trailblaze the way toward construction of spin-selective functional devices that operate at ambient temperatures. In Thrust 2, entitled Polaronic spin-transport, spin accumulation, and electrocatalysis, state-of-the-art circularly polarized XUV and femtosecond stimulated Raman spectroscopies will be used to reveal the mechanism of spin-filtered electron transport in chiral metal oxides and to demonstrate their utility as spin-filters and spin-selective photoelectrocatalysts. These studies will reveal how the spin-selectivity of chiral matter acts to optimize multi-electron redox pathways, providing fresh insights into controlling energy conversion and asymmetric chemical reactions. This work aims to address fundamental questions- Can we harness spin-filtered electron currents for use in chemical reactions? How do we best use spin-polarized electron currents with spin-selection rules to guide reactions toward desired products? Can we use spin-polarized electrons to direct chemical redox reactions toward desired enantiomerically pure products? In Thrust 3, entitled Origins and impact of spin select ivity on biochemical and biological function, the implications and applications of CISS phenomena in redox biochemistry will be explored. As all biological macromolecules are homochiral and redox reactions lie at the heart of bioenergetics and many biochemical pathways, this program investigates how spin-filtered electron currents can be used to affect redox reaction rates. The studies range from single electron transfer events in redox proteins (and enzymes) to multi-step electron transport through chains of such proteins (intracellular and extracellular) and to in vivo studies.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 06, 2024
- Source ID
- FA95502310368
Entities
People
- David H Waldeck
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Pittsburgh