Soliton based Dynamic Nuclear Polarization: an unexpected Overhauser effect in cyclic polyacetylene at high field and room temperature

26 December 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Polyacetylene, a versatile material with an electrical conductivity that can span seven orders of magnitude, is the prototypical conductive polymer. In this letter, we report an unexpected and unprecedented Overhauser Effect that increases with temperature, observed under high magnetic field of 14.1 T, in both linear and cyclic polyacetylene. Significant NMR signal enhancements ranging from 24 to 45 are obtained. The heightened sensitivity enabled the characterization of chain defects at natural abundance. The absence of end methyl group carbon-13 signals provides proof of the closed-loop molecular structure of the cyclic polyacetylene. This efficiency of the soliton based Overhauser Effect DNP mechanism at high temperature and high field holds promise for applications and extension to other conductive polymer systems.


cyclic polymer
conductive polymer
Magic Angle Spinning

Supplementary materials

Supporting information
Contains experimental and simulation details, as well as additional experimental results.


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Comment number 1, Vladimir Sapunov: Mar 29, 2024, 06:16

I assume you have discovered the effect of light saturation with Overhauser DNP. The EPR line is wide and the ODNP gain is good, which does not correspond to the intensity of the high-frequency field of the electronic pump. Similar effects were observed by Potenza in solutions of Galvinoxyl. There are also nitroxyl radicals with such effects.