TY - JOUR
T1 - Synthesis of mono-nitroxides and of bis-nitroxides with varying electronic through-bond communication
AU - Giannoulis, Angeliki
AU - Ackermann, Katrin
AU - Bogdanov, Alexey
AU - Cordes, David
AU - Higgins, Catherine
AU - Ward, Joshua
AU - Slawin, Alexandra
AU - Taylor, James
AU - Bode, Bela
N1 - Funding Information:
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). We also thank the EPSRC UK National Mass Spectrometry Facility at Swansea University, Mr Steven Boyer for elemental analyses at London Metropolitan University and Dr Thomas Lebl and Mrs Melanja Smith at the NMR facility at the University of St-Andrews.
PY - 2023/1/14
Y1 - 2023/1/14
N2 - 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 to 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.
AB - 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 to 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.
UR - http://www.scopus.com/inward/record.url?scp=85144813226&partnerID=8YFLogxK
U2 - 10.1039/d2ob01863b
DO - 10.1039/d2ob01863b
M3 - Article
VL - 21
SP - 375
EP - 385
JO - Organic and Biomolecular Chemistry
JF - Organic and Biomolecular Chemistry
SN - 1477-0520
IS - 2
ER -