An Exchange Coupled meso-meso Linked Vanadyl Porphyrin Dimer for Quantum Information Processing

Molecular multi-spin systems acting as potential quantum gates require fine-tuning magnetic interactions to achieve single spin addressability and entanglement of the spin qubits. We report here the synthesis of a new singly linked vanadyl-porphyrin dimer that crystallizes in two different pseudo-polymorphs. The single crystal continuous-wave Electron Paramagnetic Resonance investigation evidences a small but crucial isotropic exchange interaction, J, between the two tilted, and thus distinguishable, spin centers of the order of 10^-2 cm-1. The experimental and DFT studies evidence a correlation between J values and porphyrin planes tilting angle and distortion. Pulsed EPR analysis shows that the two vanadyl dimers maintain the coherence time of the monomer. Our results, coupled with the evaporability of porphyrin systems, establish this class of dimers as extremely promising for quantum information processing applications.