An azacrowned phthalimide as a metal-ion sensitive and solvatofluorochromic fluorophore: Fluorescence properties and a mimic integrated logic operation

The novel azacrowned phthalimide 1 has been prepared and its fluorescence properties have been investigated by addition of EtOH and Ag ⁺. The phthalimide 1 showed appreciable solvatofluorochromism; its fluorescence maxima (λ _FL) appeared in the wavelength region between 458 (in Et ₂O) and 544 nm (in EtOH). In benzene, the phthalimide 1 gave off blue emission (λ _FL 466 nm) while it emitted green fluorescence (λ _FL 497 nm) upon addition of 250 mM of EtOH. Both the blue and the green emissions were quenched by Ag ⁺. Potential logic operations of the phthalimide 1 were examined using fluorescence outputs at 450 (Out ₁) and 515 nm (Out ₂) and two input stimuli, EtOH (In ₁) and Ag ⁺ (In ₂). The Out ₁ was on in the absence of these inputs while its intensity was reduced (off) by either or both of the inputs to serve as a NOR operator. The Out ₂ was off without the inputs; in contrast, the intensity of Out ₂ was enhanced (on) by In ₁. The enhanced Out ₂ was switched off by In ₂. The Out ₂, thus, corresponds to an INHIBIT operation responding to the input signals. The crowned phthalimide 1 mimics a two-input-two-output combinational logic gate with a single fluorophore and a single ion-sensing unit.