Modelling Conformational Flexibility in a Spectrally Addressable Molecular Multi‐Qubit Model System

• Published in: Angewandte Chemie International Edition Vol. 61; no. 45; pp. e202207947 - n/a
• Main Authors: Rogers, Ciarán J., Asthana, Deepak, Brookfield, Adam, Chiesa, Alessandro, Timco, Grigore A., Collison, David, Natrajan, Louise S., Carretta, Stefano, Winpenny, Richard E. P., Bowen, Alice M.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 07-11-2022; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Algorithms; Chemical synthesis; Communication; Communications; Data processing; Electron paramagnetic resonance; Electron spin; Electron spin resonance; Electron Spin Resonance Spectroscopy - methods; Electrons; Heterometallic Complexes; Information processing; Models, Molecular; Molecular Conformation; Molecular Magnetism; Multi-Spin; Nitroxide; Pulsed Dipolar Spectroscopy; Quantum Information Processing; Quantum phenomena; Qubits (quantum computing); Resonance; Pulsed Dipolar Spectroscopy; Heterometallic Complexes; Multi-Spin; Molecular Magnetism; Quantum Information Processing
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202207947

Dipolar coupled multi‐spin systems have the potential to be used as molecular qubits. Herein we report the synthesis of a molecular multi‐qubit model system with three individually addressable, weakly interacting, spin
1/2
${{ 1/2 }}$
centres of differing g‐values. We use pulsed Electron Paramagnetic Resonance (EPR) techniques to characterise and separately address the individual electron spin qubits; CuII, Cr7Ni ring and a nitroxide, to determine the strength of the inter‐qubit dipolar interaction. Orientation selective Relaxation‐Induced Dipolar Modulation Enhancement (os‐RIDME) detecting across the CuII spectrum revealed a strongly correlated CuII‐Cr7Ni ring relationship; detecting on the nitroxide resonance measured both the nitroxide and CuII or nitroxide and Cr7Ni ring correlations, with switchability of the interaction based on differing relaxation dynamics, indicating a handle for implementing EPR‐based quantum information processing (QIP) algorithms.
Systems with weak dipolar interactions have the potential to be used for molecular quantum computing. Orientation selective pulsed EPR was used to model the conformational flexibility of a molecular multi‐qubit model system. Spectrally addressable centres allowed for the individual manipulation of each spin qubit, while differing relaxation dynamics resulted in a proposed handle for the implementation of quantum algorithms.