A Synthetic Two‐Spin Quantum Bit: g‐Engineered Exchange‐Coupled Biradical Designed for Controlled‐NOT Gate Operations

A quantum gate: A system of two coupled electron spins that is useful for simple quantum computing operations has been prepared by synthesis of a biradical 1 and co-crystallization with an isomorphous host molecule. The two weakly exchange-coupled quantum bits (target qubit blue and control qubit red) span four electron spin states. The electron spin transition is denoted by two black arrows.