Heteroleptic Cr4+ molecular color center candidates
7 affiliations
- 1Department of Chemistry, Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA
- 2Department of Chemistry, Columbia University New York New York 10027 USA
- 3National High Magnetic Field Laboratory, Florida State University Tallahassee Florida 32310 USA
- 4Department of Chemistry, Northwestern University Evanston Illinois 60208 USA
- 5Pritzker School of Molecular Engineering, University of Chicago Chicago Illinois 60637 USA
- 6Department of Physics, University of Chicago Chicago Illinois 60637 USA
- 7Initiative for Computational Catalysis, Flatiron Institute New York New York 10010 USA
Abstract
Most quantum sensing experiments require the creation of a spin-optical interface, where optical light can polarize and read out information from spin sublevels. This combination creates a sensor capable of detection down to the single-spin limit. Heteroleptic coordination complexes are promising architectures for enabling positional control of spins in quantum sensing experiments. Towards this end, we use complementary magnetic and optical spectroscopies supported by multiconfigurational electronic structure calculations to establish the first generation of heteroleptic S = 1 Cr4+ complexes as molecular color center candidates. This family of trigonal bipyramidal tris[2-(trimethylsilylamido)ethyl]amine chromium–halide complexes, referenced here as TMStrenCrX (X = F, Cl, Br, and I, respectively known as 1, 2, 3, and 4), exhibits highly modular magnetic and optical properties. 1–4 display largely axial zero-field splitting (ZFS) characterized by high-field, high-frequency continuous-wave electron paramagnetic resonance (HFHF cw-EPR) spectroscopy, where the axial ZFS parameter D continually increases from +5.194(4) cm−1 (1) to +7.34(1) cm−1 (4) as halide donor strength weakens. 1–4 also display near-infrared spin-flip photoluminescence (PL) ranging from 959.57(1) to 1043.81(1) nm. These PL spectra exhibit traits critical for enabling optical addressability, such as optical linewidths narrow enough to rival the magnitude of ZFS. A dilute sample of 4 in its Ti4+ diamagnetic host (4′) even displays optically resolvable spin sublevels under zero applied magnetic field; using variable-field PL spectroscopy, we optically determine its ZFS parameters. These results will lead toward the realization of well-defined spin-analyte interactions and subsequent spatial control of molecular color centers, wherein tunability is maintained through the donor at the axial coordination site.
Related
- Correlative super-resolution microscopy reveals preferential localization of quantum color center formation on carbon nanotubes
- Crystalline ASR products: Review of mineral candidates and molecular simulations of their atomic structures, thermodynamic data and thermoelastic properties
- Electrochemiluminescence of Heteroleptic Iridium(III) Complexes Featuring Substituted 2,4‐diphenylpyridinato Ligands
- Millisecond-Long Red Phosphorescence in Chiral Heteroleptic Ag(I) Complexes Bearing Benzothiazole Ligands
- Heteroleptic Ag(I) Complexes Bearing Benzothiazole and Benzoxazole Ligands for Orange‐Red Light‐Emitting Electrochemical Cells
BibTeX
@article{massado2026heteroleptic,
title = {{Heteroleptic Cr4+ molecular color center candidates}},
author = {Cindy Serena Ngompe Massado and Rianna B. Greer and Arailym Kairalapova and Andrew Ozarowski and Kelsey A. Collins and Majed S. Fataftah and Noah Mendelson and Chloe A. Washabaugh and Daniel W. Laorenza and Michael K. Wojnar and David D. Awschalom and Timothy C. Berkelbach and Danna E. Freedman},
journal = {Chemical Science},
year = {2026},
month = sep,
doi = {10.1039/d6sc05602d},
url = {https://doi.org/10.1039/d6sc05602d},
note = {CC BY 3.0},
}
RIS
TY - JOUR
TI - Heteroleptic Cr4+ molecular color center candidates
AU - Cindy Serena Ngompe Massado
AU - Rianna B. Greer
AU - Arailym Kairalapova
AU - Andrew Ozarowski
AU - Kelsey A. Collins
AU - Majed S. Fataftah
AU - Noah Mendelson
AU - Chloe A. Washabaugh
AU - Daniel W. Laorenza
AU - Michael K. Wojnar
AU - David D. Awschalom
AU - Timothy C. Berkelbach
AU - Danna E. Freedman
PY - 2026
DA - 2026/09/18
JO - Chemical Science
DO - 10.1039/d6sc05602d
UR - https://doi.org/10.1039/d6sc05602d
AB - Most quantum sensing experiments require the creation of a spin-optical interface, where optical light can polarize and read out information from spin sublevels. This combination creates a sensor capable of detection down to the single-spin limit. Heteroleptic coordination complexes are promising architectures for enabling positional control of spins in quantum sensing experiments. Towards this end, we use complementary magnetic and optical spectroscopies supported by multiconfigurational electronic structure calculations to establish the first generation of heteroleptic S = 1 Cr4+ complexes as molecular color center candidates. This family of trigonal bipyramidal tris[2-(trimethylsilylamido)ethyl]amine chromium–halide complexes, referenced here as TMStrenCrX (X = F, Cl, Br, and I, respectively known as 1, 2, 3, and 4), exhibits highly modular magnetic and optical properties. 1–4 display largely axial zero-field splitting (ZFS) characterized by high-field, high-frequency continuous-wave electron paramagnetic resonance (HFHF cw-EPR) spectroscopy, where the axial ZFS parameter D continually increases from +5.194(4) cm−1 (1) to +7.34(1) cm−1 (4) as halide donor strength weakens. 1–4 also display near-infrared spin-flip photoluminescence (PL) ranging from 959.57(1) to 1043.81(1) nm. These PL spectra exhibit traits critical for enabling optical addressability, such as optical linewidths narrow enough to rival the magnitude of ZFS. A dilute sample of 4 in its Ti4+ diamagnetic host (4′) even displays optically resolvable spin sublevels under zero applied magnetic field; using variable-field PL spectroscopy, we optically determine its ZFS parameters. These results will lead toward the realization of well-defined spin-analyte interactions and subsequent spatial control of molecular color centers, wherein tunability is maintained through the donor at the axial coordination site.
SN - 2041-6520
SN - 2041-6539
ER -