Molecular logic gates

Ion-induced photophysical phenomena yield signals varying in intensity and/or color, and when viewed from a different vantage point, these changes can be correlated with the binary response of Boolean logic gates. The photoinduced electron transfer (PET) is particularly appropriate for this purpose, because the changes observed by the modulation of the thermodynamics of PET with different inputs (analytes) usually yields “off-on” type, clear digital action. For two binary variables, there are 16 different types of Boolean functions, and molecular logic gates are available for most of them. There are considerable hurdles to overcome in reaching practically useful information processing at the molecular level, such as individual addressability and higher levels of integration, further refinement of functionally integrated combinatorial circuits is essential. It would be highly desirable to have arithmetic operators which produce the same kind of output with very sharp changes in the studied parameter. Fluorescence, being an essentially zero-background technique, has clear advantages as output. The changes in the emission spectrum can also be followed at more than one wavelength, resulting in more than one logic function in a single molecular or supramolecular system. This has been first demonstrated by us[1] (vide supra) and then recognized as a powerful tool[2] for obtaining multiple logic expressions.

Relevant Publications: [1] [2]