Copper(ii) catalyzed synthesis of novel helical luminescent benzo[4,5]imidazo[1,2-a][1,10]phenanthrolines via an intramolecular C–H amination reaction

Abstract

In the present study a series of N-phenyl-1,10-phenanthroline-2-amine derivatives were obtained by heating 2-chlorophenanthroline with aniline derivatives under solvent free conditions in good to excellent yields. The N-phenyl-1,10-phenanthroline-2-amines were employed as substrates in a copper(ii)-catalyzed C-H amination reaction to give derivatives of the novel heterocyclic system benzo[4,5]imidazo[1,2-a][1,10]phenanthroline. The structure of these compounds was predicted to be helical by DFT calculations and single crystal X-ray diffraction of an example of this system confirmed the non-planar helical structure. The luminescence properties of the parent heterocyclic system were characterized.

Photophysical Properties of Fluorescent 2‐(Phenylamino)‐1,10‐phenanthroline Derivatives†

“…Derivatives of 2‐(phenylamino)‐1,10‐phenanthroline ( 1a–n ) were prepared in an analogous manner to that previously described (37). The spectroscopic and spectrometric data for the previously unreported derivative 1g corroborate the structure of 1g .…”

“…The solids were isolated by filtration, washed with 50% aqueous EtOH and air‐dried. These compounds have been previously spectroscopically (IR, NMR) and spectrometrically (HRMS) characterized and their purity confirmed by NMR and chromatographic techniques (TLC, GC‐MS) (37).…”

“…Of these isomeric compounds, the meta ‐isomer possessed the largest photoluminescent quantum yield (82%) (35). Additionally, substitution at the 3,8‐positions to build polymers has been reported (36), and oxidative C‐H amination of N ‐(phenyl)‐2‐aminophenanthrolines resulted in the intensely fluorescent, helical, benzoimidazophenanthrolines (37–39).…”

Synthesis and Photophysical Properties of α-(N-Biphenyl)-Substituted 2,2′-Bipyridine-Based Push–Pull Fluorophores

“…Several isomeric amino-substituted 2,2′-bipyridines were reported as fluorescent indicators for Zn (II) and fluorescent dyes for the imaging of prostate cells [ 14 ]. Finally, arylamino-2,2′-bipyridines were reported as convenient synthons for the construction of various fused polynuclear systems [ 15 , 16 , 17 ].…”

Palladium-Catalyzed Electro-oxidative C–H Amination toward the Synthesis of Pyrido[1,2-a]benzimidazoles with Hydrogen Evolution

“…Pyrido­[1,2- a ]­benzimidazole is a primary motif in medicinal chemistry, especially in some bioactive molecules, for example, antimalarial and anticancer agents, or antitumor , and antiviral agents (Figure ). Consequently, substantial methods have been developed to construct pyrido­[1,2- a ]­benzimidazole and its derivatives via the annulation of N -phenylpyridin-2-amines, which is one of the most straightforward paths. , In 2010, a Cu-catalyzed annulation of N -phenylpyridin-2-amine was first achieved to produce pyrido­[1,2- a ]­benzimidazoles from N -( p -tolyl)­pyridin-2-amines (Scheme A). After that, I 2 and organohypervalent iodine reagents were found to be effective to induce this process as oxidants − (Scheme B).…”