Tunable Cr 4+ Molecular Color Centers

The inherent atomistic precision of synthetic chemistry enables bottom-up structural control over quantum bits, or qubits, for quantum technologies. Tuning paramagnetic molecular qubits that feature optical-spin initialization and readout is a crucial step toward designing bespoke qubits for applications in quantum sensing, networking, and computing. Here, we demonstrate that the electronic structure that enables optical-spin initialization and readout for = 1, Cr(aryl) , where aryl = 2,4-dimethylphenyl ( ), -tolyl ( ), and 2,3-dimethylphenyl ( ), is readily translated into Cr(alkyl) compounds, where alkyl = 2,2,2-triphenylethyl ( ), (trimethylsilyl)methyl ( ), and cyclohexyl ( ). The small ground state zero field splitting values (