A pair of regio-isomeric compounds acting as molecular logic gates with different functions

Regioisomers 6a and 6b display different spectral properties towards pH and surfactant concentration. For compound 6a, an obvious color change from yellow to red and significant fluorescence quenching were observed upon addition of acid, whereas large enhancements in emission and absorption intensities of 6b were found with decreasing pH value. CTAB and Triton X-100 enhanced the fluorescence intensity of both dyes. Small amount of SDS (less than its cmc) quenched, while large amount of SDS ([SDS] > cmc) recovered the fluorescence of 6a and 6b. 6a and 6b can execute different Boolean operations: much more logic functions can be implemented with 6a in SDS system, while half addition can be realized with 6b when both inputs are SDS.