Digital Operations with Molecules - Advances, Challenges, and Perspectives

This Review gives a short introduction into molecular logic and focusses then on the latest advances in the field. With regard to complex logic circuits and functions, molecular devices for arithmetic processing (adders and subtractors), multiplexers/demultiplexers, and encoders/decoders are discussed. Further on, the concept of memory for data storage and sequential logic is considered together with the latest results on molecular keypad locks. Molecular logic has been often connected to the future aim of molecular computing. However, albeit the herein described approaches constitute a starting point, major challenges like concatenation of gates, solid state devices and compartmentalization, and alternative concepts (reversible logic, multivalued logic) are waiting ahead. These points are included, as well as a view on alternative applications of molecular logic in bio-inspired approaches, combinatorial chemistry, and materials science.