Aggregation induced emission based active conjugated imidazole luminogens for visualization of latent fingerprints and multiple anticounterfeiting applications.

Aggregation-induced emission based organic heterocyclic luminogens bearing conjugated electronic structures showed much attention due to its excellent fluorescence in aggregation state. In this communication, a novel conjugated blue light emitting imidazole molecule is synthesized by one pot multicomponent reaction route is reported for the first time. The prepared molecule exhibits a strong fluorescence in aggregation state with exceptional properties, such as high purity, inexpensive, eco-friendly, large scale production, high photostability, etc. By considering these advantages, a new fluorescence based platform has been setup for in-situ visualization of latent fingerprints and its preservation by spray method followed by Poly(vinyl alcohol) masking. A clear and well defined fluorescence fingerprint images are noticed on variety of surfaces by revealing level 1-3 ridge features upon ultraviolet 365 nm light exposure. The dual nature of binding specificity as well as excellent fluorescence properties permits the visualization of latent fingerprints for longer durations (up to 365 days) with superior contrast, high sensitivity, efficiency, selectivity and minimal background hindrance. We further fabricated unclonable invisible security ink for various printing modes on valuable goods for protection against forging. The developed labels are displaying uniform distribution of ink and exceptional stability under various atmospheric environments. The development of long preservative information using aggregation-induced emission based luminogen opens up a new avenue in advanced forensic and data security applications.

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

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.