Mao Haochuan, Young Ryan M, Krzyaniak Matthew D, Wasielewski Michael R
Department of Chemistry, Center for Molecular Quantum Transduction, and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, United States.
J Phys Chem Lett. 2021 Mar 11;12(9):2213-2218. doi: 10.1021/acs.jpclett.1c00077. Epub 2021 Feb 25.
Photogenerated entangled electron spin pairs provide a versatile source of molecular qubits. Here, we examine the spin-dependent dynamics of a covalent donor-acceptor-radical molecule, D-A-R, where the donor chromophore (D) is -xanthenoxanthene (PXX), the acceptor (A) is pyromellitimide (PI), and the radical (R) is α,γ-bisdiphenylene-β-phenylallyl (BDPA). Selective photoexcitation of D within D-A-R in butyronitrile/propionitrile at 140 K and butyronitrile at 105 K results in the spin-selective reactions D-A-R → D-(A-R) and D-(A-R). Subsequently, at 140 K, D-(A-R) → D-A-R, whereas D-(A-R) → D-A-R. In contrast, at 105 K, D-(A-R) → D-A-R and D-A-R. Time-resolved EPR spectroscopy shows that D-A-R is highly spin-polarized, where the = ±1/2 spin sublevels of the doublet-quartet manifolds are selectively populated. These results demonstrate dielectric environment control over different spin states in the same molecule.
光生纠缠电子自旋对提供了一种通用的分子量子比特源。在这里，我们研究了一种共价供体-受体-自由基分子D-A-R的自旋相关动力学，其中供体发色团（D）是-呫吨-呫吨（PXX），受体（A）是均苯四甲酸二酰亚胺（PI），自由基（R）是α,γ-双亚苯基-β-苯基烯丙基（BDPA）。在140 K的丁腈/丙腈和105 K的丁腈中对D-A-R中的D进行选择性光激发，会导致自旋选择性反应D-A-R → D-(A-R)和D-(A-R)。随后，在140 K时，D-(A-R) → D-A-R，而D-(A-R) → D-A-R。相比之下，在105 K时，D-(A-R) → D-A-R和D-A-R。时间分辨电子顺磁共振光谱表明D-A-R具有高度自旋极化，其中双重态-四重态流形的 = ±1/2自旋子能级被选择性填充。这些结果证明了介电环境对同一分子中不同自旋态的控制。
