New design of highly sensitive AIE based fluorescent imidazole derivatives: Probing of sweat pores and anti-counterfeiting applications

Abstract

A novel aggregation induced emission based 2-(1-(3, 5-bis(trifluoromethyl)phenyl)-4,5- diphenyl-1H-imidazol-2-yl) phenol (4) (IMD) fluorescent tags (FTs) was designed by simple acid catalyzed five-member N-heterocyclic ring forming reaction process. Powder X-ray diffraction results showed mechanofluorochromic properties of IMD FTs are easily reversible under external force due to the decrease in crystallinity. These IMD FTs also exhibits strong cyan-blue luminescence in solid state with high quantum efficiency. Detailed investigation of latent fingerprints (LFPs) showed permanent, immutable and unique pores that are distributed on the ridges. The visualization of such sweat pores opens new avenue in the field of forensic science. Hence, the prepared IMD FTs exhibit excellent Lipophicity (LP) properties, which endorse its possible applications for the visualization of sweat pores present in the LFPs. The LFPs visualized by IMD FTs exhibit excellent efficiency, sensitivity, selectivity, low background hindrance and less toxicity. The obtained result evident that the prepared FT and followed technique opens possible applications for the visualization of LFPs on various porous/semi-porous/non-porous surfaces under UV 365 nm light.