Rigidifying Qubit Candidates in a Cu‐Porphyrin Nanohoop: Dipolar Coupling in Spin Pairs and Spin‐Polarized Ground State
Abstract
Abstract Assembling molecular qubit candidates with precise control over the position and orientation of spin centers is an important contemporary challenge for synthesis. In this work, we show that the rigidity of highly strained macrocycles from the cycloparaphenylene family gives rise to distinct spin‐spin and light‐spin interactions that make such few‐qubit systems a promising testing ground for future quantum technologies. We synthesized conjugated nanohoop Cu[3]CPTA that comprises three Cu(II)porphyrin centers ( S = ½) with a Cu–Cu distance of ca. 18 Å (by single‐crystal X‐ray diffraction). Continuous‐wave (cw) and pulse electron‐paramagnetic resonance (EPR) studies revealed that dipolar coupling in spin pairs is so well defined in this nanohoop that the Cu–Cu distance can be determined accurately via double electron–electron resonance (DEER). By transient cwEPR, we observed a rare case of a light‐induced polarization of a doublet ground state in frozen solution. The fact that ground state polarization was significantly less pronounced in a comparable, but more flexible macrocycle will inspire future efforts to better understand and harness this effect.
Article Details
Authors (13)
Xingmao Chang
Ashley J. Redman
Chemistry Research Laboratory, Department of Chemistry
Linda Zedler
Leibniz Institute of Photonic Technology, Research Department Spectroscopy and Imaging, Albert-Einstein-Str. 9, Jena 07745, Germany
Louis Blechschmidt
Institute of Physical Chemistry
Adriana Sacristán‐Martín
Institute of Organic Chemistry and Center for Integrated Quantum Science and Technology Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
Fabian Schwer
Institute of Organic Chemistry and Center for Integrated Quantum Science and Technology Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
Inhar Imaz
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, Barcelona, Spain
Markus P. B. Wiedmaier
Institute of Organic Chemistry and Center for Integrated Quantum Science and Technology Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany
Xavi Ribas
Institut de Quimica Computacional i Catalisi, Departament de Quimica
Daniel Maspoch
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC, and The Barcelona Institute of Science and Technology
Benjamin Dietzek‐Ivanšić
Institute for Physical Chemistry Friedrich Schiller University Jena Helmholtzweg 4 07743 Jena Germany
Sabine Richert
Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104 Freiburg, Germany
Max von Delius
Institute of Organic Chemistry and Center for Integrated Quantum Science and Technology Ulm University Albert‐Einstein‐Allee 11 89081 Ulm Germany