(411i) Spin Selective Chiral Open-Shell Molecules

Spintronic materials and devices are emerging as promising candidates for multiple applications; however, most work has focused on inorganic materials that have large spin-orbit couplings (SOCs). When an external magnetic field is applied to these large-SOC, generally ferromagnetic materials, a significant amount of spin alignment impacts their overall charge transport. In contrast, organic materials have not played a significant role in this field due to their weak SOC, which does not significantly affect spin transport. However, when current passes through a chiral nanostructure, particularly those with a spiral-like molecular shape, large amounts of spin polarization are observed. This phenomenon is called the chirality-induced spin selection (CISS) effect. To date, only diamagnetic chiral organic materials, which are not conductive, have been applied to achieve CISS effect to the materials. However, chiral radical molecules could act as both charge transport carriers and chirality-dependent electronic spin polarization materials. Furthermore, alignment of the paramagnetic spins of the radicals itself could result in either amplifying or suppressing the CISS effect, depending on the direction between external magnetic field versus helix structure orientation. Therefore, we have synthesized a set of right- and left-handed diradical molecules (i.e., a 1,1′-bi-2-naphthol (BINOL) derivative) through simple reaction pathways, and we have evaluated their electronic and magnetic behavior using a combined experimental and computational approach. Depending on the molecular structure, a different current response was observed under application of the same magnetic field. Therefore, this study is the first attempt to apply chiral radical molecules in CISS effect, along to be one of the first study to observe magnetic and conductive behaviors of chiral radical molecules itself. This unique design of chiral open-shell molecules affords a promising, high-performance system to enable new spintronic device designs.