Synthesis of mono-nitroxides and of bis-nitroxides with varying electronic through-bond communication
Abstract
Nitroxides are a unique class of persistent radicals finding a wide range of applications, from spin probes to polarizing agents, and recently bis-nitroxides have been used as proof-of-concept molecules for quantum information processing. Here we present the syntheses of pyrroline-based nitroxide (NO) radicals and give a comparision of two possible synthetic routes to form two key intermediates, namely 2,2,5,5-tetramethylpyrroline-1-oxyl-3-acetylene (TPA) and 1-oxyl-2,2,5,5-tetramethylpyrroline-3-carboxylic acid (TPC). TPC and TPA were then used as precursors for the synthesis of three model compounds featuring two distant NO groups with a variable degree of conjugation and thus electronic communication between them. Using relatively facile synthetic routes, we produced a number of mono- and bis-nitroxides with the structures of multiple compounds unambiguously characterized by X-ray crystallography, while Continuous Wave Electron Paramagnetic Resonance (CW-EPR) allowed us quantify the electronic communication in the bis-nitroxides. Our study expands the repertoire of mono- and bis-nitroxides with possibilities of exploiting them for studying quantum coherence effects and as polarizing agents.
Citation
Giannoulis , A , Ackermann , K , Bogdanov , A , Cordes , D B , Higgins , C , Ward , J , Slawin , A M Z , Taylor , J E & Bode , B E 2023 , ' Synthesis of mono-nitroxides and of bis-nitroxides with varying electronic through-bond communication ' , Organic & Biomolecular Chemistry , vol. 21 , no. 2 , pp. 375-385 . https://doi.org/10.1039/D2OB01863B
Publication
Organic & Biomolecular Chemistry
Status
Peer reviewed
ISSN
1477-0520Type
Journal article
Rights
Copyright The Author(s). Open Access. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Description
Funding: AG acknowledges the UK-MRBT-CDT funded by EPSRC (EP/J500045/1), BEB acknowledges the Wellcome Trust Institutional Strategic Support fund (204821/Z/16/Z), JET acknowledges the Leverhulme Trust (Early Career Fellowship; ECF-2014-005).Collections
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