Region Selective Fluorescent Sensor for Al 3+ and Pyrophosphate Ions: H‐Bonding Induced Aggregation with Potential Applications for INHIBIT and EXOR Logic Devices

A chemical sensor, labelled L , created through a Schiff base reaction, was observed to specifically identify aluminum ions (Al 3+ ) and inorganic pyrophosphate (PPi) in a water‐methanol solution (80% methanol, 20% water) at a pH of 7.2. The sensor produced a blue light signal (486 nm) in response to aluminum ions and a green light signal (534 nm) when detecting inorganic pyrophosphate. The synthesized chemosensor and its complex with Al 3+ were confirmed by MS (m/z) studies. The most intriguing finding of this research is the change in spectral properties of the L + Al 3+ complex with the addition of PPi, in which the fluorescence property of L +Al 3+ complex is completely suppressed. However, upon adding more PPi, a new fluorescent signal emerged at a green wavelength (534 nm). Notably, this sensing process can be reversed, and the sensor's behavior closely resembles the functions of logic gates (INHIBIT and EXOR). Most strikingly, it was observed that the free probe undergoes aggregation through intermolecular H‐bonding interactions to form nano‐structures (91 nm). In the presence of Al 3+ , it undergoes further aggregation to give microstructures with particle size varying between 0.40 and 4.23 µ m, while in the presence of PPi the size is ∼ 130 nm, but in the presence of both Al 3+ and PPi it forms an extended 2D‐sheet‐like microstructure. The findings were substantiated by a combination of techniques including dynamic light scattering (DLS), traditional optical microscopy, fluorescence microscopy, and field emission scanning electron microscopy.