Resettable Multiple-Mode Molecular Arithmetic Systems Based on Spectral Properties of 2-Quinolin-2-ylmethylene-malonic Acids

The development of molecular arithmetic systems is very crucial for the realization of a molecule-scale calculator (a Moleculator). In this work, two compounds with pH-sensitive functional groups, 2-quinolin-2-ylmethylene-malonic acids (QMA-1 and QMA-2), have been prepared for molecular algebraic operations. These compounds can exist in several ionization forms (cationic, neutral, and anionic), each of which has distinct spectral properties, and can be applied in the construction of acid/base-boosted molecular Boolean arithmetic functions including half-subtractor, half-adder, full-subtractor, and full-adder. A half adder x + y and a bidirectional half-subtractor, x – y and y – x, have been obtained on the basis of the absorption of QMA-1, whose absorption values at certain wavelengths are applied as signal outputs, using a base as chemical input. A molecular full-adder x + y + C in and a molecular full-subtractor x – y – B in have also been achieved through utilizing a combined fluorescence from a single solution containing both QMA-1 and QMA-2 as output signals and acid/base as chemical inputs. These systems are resettable after each separate arithmetic operation.