A self-assembled metallo-macrocycle two-qubit spin system.

A self-assembled, charge-neutral dicopper(II) metallo-macrocycle with a near degenerate singlet-triplet ground state is a prototype molecular two-qubit system. The weakly-coupled spin centres delivered a long phase memory time of 5.4 μs, and each spin can be selectively switched using an applied potential providing a convenient means to modulate the quantum levels.