Interaction of Photogenerated Spin Qubit Pairs with a Third Electron Spin in DNA Hairpins

J Am Chem Soc. 2021 Mar 31;143(12):4625-4632. doi: 10.1021/jacs.0c12645. Epub 2021 Mar 18.

Abstract

The designing of tunable molecular systems that can host spin qubits is a promising strategy for advancing the development of quantum information science (QIS) applications. Photogenerated radical pairs are good spin qubit pair (SQP) candidates because they can be initialized in a pure quantum state that exhibits relatively long coherence times. DNA is a well-studied molecular system that allows for control of energetics and spatial specificity through careful design and thus serves as a tunable scaffold on which to control multispin interactions. Here, we examine a series of DNA hairpins that use naphthalenediimide (NDI) as the hairpin linker. Photoexcitation of the NDI leads to subnanosecond oxidation of guanine (G) within the duplex or a stilbenediether (Sd) end-cap to give NDI•--G•+ or NDI•--Sd•+ SQPs, respectively. A 2,2,6,6-tetramethylpiperdinyl-1-oxyl (TEMPO) stable radical is covalently attached to the hairpin at varying distances from the SQP spins. While TEMPO has a minimal effect on the SQP formation and decay dynamics, EPR spectroscopy indicates that there are significant spin-spin dipolar interactions between the SQP and TEMPO. We also demonstrate the ability to implement more complex spin manipulations of the NDI•--Sd•+-TEMPO system using pulse-EPR techniques, which is important for developing DNA hairpins for QIS applications.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • DNA / chemistry*
  • Electrons*
  • Imides / chemistry*
  • Molecular Structure
  • Naphthalenes / chemistry*
  • Photochemical Processes
  • Quantum Theory*

Substances

  • Imides
  • Naphthalenes
  • naphthalenediimide
  • DNA