N,N-Dimethyl-4-amino-2,1,3-benzothiadiazole: Synthesis and Luminescent Solvatochromism

N,N-Dimethyl-4-amino-2,1,3-benzothiadiazole (BTDNMe2) was synthesized from the commercially available 2,1,3-benzothiadiazole (BTD) by nitration in a sulfonitric mixture, followed by a reduction of the nitro group and subsequent methylation with iodomethane. BTDNMe2 was fully characterized by means of nuclear magnetic resonance (NMR) and infrared spectroscopy. The solutions of BTDNMe2 in common organic solvents revealed to be appreciably luminescent in the visible range. The electronic transitions related to the absorption and emission properties were associated with the HOMO–LUMO energy gap by means of electrochemical measurements and DFT calculations. Finally, BTDNMe2 was successfully used to prepare luminescent-doped poly(methyl methacrylate) samples.