Establishing Optical-Spin Interfaces in Luminescent Organic Diradicals using Spin-selective Symmetry-breaking Charge Transfer
Abstract
Luminescent organic diradicals based on tris(2,4,6-trichlorophenyl)methyl (TTM) radicals have shown promise as optical-spin interfaces important for quantum sensing. The optically driven spin polarization mechanisms of existing TTM diradicals remain limited by non-selective singlet-triplet intersystem crossing (ISC) pathways, which restrict optically detected magnetic resonance (ODMR) contrast. Two TTM-based diradicals were prepared in which the two TTM subunits are linked at the para positions of one of their phenyls. Fully substituting the resulting biphenyl linkage between the radical centers with chlorines gives diradical 1, in which the two phenyls constituting the linkage are nearly orthogonal to one another. Subsequent replacement of the remaining four para positions of the TTM phenyls with p-tolyl groups gives diradical 2. Following photoexcitation of these diradicals to their triplet excited states, they undergo symmetry-breaking charge transfer to form a diamagnetic ion pair followed by charge recombination to form a spinpolarized triplet state. Diradical 2 shows spin-selective intersystem crossing from the triplet excited state resulting in an ODMR spectrum, while diradical 1 does not. These results show that spin-selective decay channels from the triplet excited state are a necessary requirement for establishing a spin-optical interface in TTM-based diradicals.
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BibTeX
@misc{wang2026establishing,
title = {{Establishing Optical-Spin Interfaces in Luminescent Organic Diradicals using Spin-selective Symmetry-breaking Charge Transfer}},
author = {Yixi Wang and Kathryn R. Peinkofer and Jonathan R. Palmer and Kyle T. Kairys and Rafael López-Arteaga and Ryan M. Young and Matthew D. Krzyaniak and Michael R Wasielewski},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009671/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009671/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Establishing Optical-Spin Interfaces in Luminescent Organic Diradicals using Spin-selective Symmetry-breaking Charge Transfer
AU - Yixi Wang
AU - Kathryn R. Peinkofer
AU - Jonathan R. Palmer
AU - Kyle T. Kairys
AU - Rafael López-Arteaga
AU - Ryan M. Young
AU - Matthew D. Krzyaniak
AU - Michael R Wasielewski
PY - 2026
DA - 2026/09/29
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009671/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009671/v1
AB - Luminescent organic diradicals based on tris(2,4,6-trichlorophenyl)methyl (TTM) radicals have shown promise as optical-spin interfaces important for quantum sensing. The optically driven spin polarization mechanisms of existing TTM diradicals remain limited by non-selective singlet-triplet intersystem crossing (ISC) pathways, which restrict optically detected magnetic resonance (ODMR) contrast. Two TTM-based diradicals were prepared in which the two TTM subunits are linked at the para positions of one of their phenyls. Fully substituting the resulting biphenyl linkage between the radical centers with chlorines gives diradical 1, in which the two phenyls constituting the linkage are nearly orthogonal to one another. Subsequent replacement of the remaining four para positions of the TTM phenyls with p-tolyl groups gives diradical 2. Following photoexcitation of these diradicals to their triplet excited states, they undergo symmetry-breaking charge transfer to form a diamagnetic ion pair followed by charge recombination to form a spinpolarized triplet state. Diradical 2 shows spin-selective intersystem crossing from the triplet excited state resulting in an ODMR spectrum, while diradical 1 does not. These results show that spin-selective decay channels from the triplet excited state are a necessary requirement for establishing a spin-optical interface in TTM-based diradicals.
ER -