A multifunctional arithmetical processor model integrated inside a single molecule

Improving the processing power of molecules remains the challenge for molecular logic and computation. Here we report a 2-phenylimidazo[4,5-f][ 1,10] phenanthroline(PIPH)-based three-state molecular switch by controlling its unique emission and absorption spectra in the acid and base condition. On one hand, PIPH can perform simultaneously the functions of an AND gate and an XOR gate, capable of operating as a half-adder, and the off-on-off function as well as comparison function by monitoring its fluorescent spectral changes. On the other hand, the molecule can also implement in parallel the functions of an XOR gate and two INH gates by monitoring its absorption spectral changes, which constructs two half-subtractors. The cooperative operation of comparator and half-subtractor makes general subtraction operation become possible, which is discussed conceptually in the report.