Synthesis of novel benzocoronene tetracarboxdiimides for fluorescent imaging of latent fingerprints

Abstract

Benzocoronene tetracarboxdiimide (CDI 1a) is prepared by ring annulation of perylene diimide via Suzuki coupling and sunlight-driven photocyclization reactions. Oxidative photocyclization predominantly occurred at the carbon position ortho to the CHO group. It is demonstrated to undergo aggregation in 30 % DMF: H2O with degree of aggregation and Franck-Condon factor value reaches 0.94 and 0.64, respectively. The emission spectrum of CDI 1a shows monomer band at 568 nm in DMF and aggregation band at 688 nm in 30 % DMF: H2O with onset of emission color from yellow to reddish-pink. These near-IR fluorescent aggregates are proved to be an ideal fluorescent material for imaging LFPs using solution and powder-dusting methods. The papillary ridges detail (1st and 2nd level of information) on various non-porous surfaces (aluminum, steel, compact disc, glass etc.) and porous surfaces (paper, floor tiles) are presented by CDI 1a.