Two (tetrahydrodibenzo[a,i]phenanthridin-5yl)phenols that differ in their substituents at the para position (P1, R = H and P2, R = NEt 2 ) were designed and synthesized. The presence of a −NEt 2 group in probe P2 facilitates the twisted intramolecular charge transfer (TICT) process, making P2 emissive, which distinctly coordinated with boron trifluoride in the presence of different amines with different electronic properties. A substantial increase in emission intensity with increasing viscosity of the surrounding environment and smooth formation of a planar complex with boron and Zn 2+ ions concluded the presence of a TICT process. The selective reactivity of P2 toward a tetracoordinated boron complex has been explored as a potential tool for colorimetric and fluorescent discrimination of aromatic primary amines, i.e., anilines. Selective detection of aniline with probe P2 can be viewed through the naked eye, and the corresponding fluorescence turn-on detection limit was found to be 12.65 nM. In addition, the detection of aniline on precoated aluminum-backed thin-layer chromatography plates and Whatman filter paper strips was found to be in good agreement with the color change of P2 in solution and in vapor phase.

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A new sulfur-bearing phenanthridine probes were synthesized and examined for their cation recognition abilities towards different cations in aqueous ACN solution and paper strips.

magnified image The one‐pot reaction of 2‐tetralone with ammonium acetate and substituted benzaldehydes affords in a good yield of 5‐aryl‐7,8,13,14‐tetrahydrodibenzo[a,i]phenanthridine or 2,4‐diaryl‐6,7‐benzo‐3‐azabicyclo[3.3.1]nonan‐9‐one. The course of the reaction seems to be dictated by the position of the substituents present on the benzaldehyde ring. J. Heterocyclic Chem., (2009).

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