Synthesis, photophysical properties and electroluminescence characterization of 1-phenyl-1H-phenanthro[9,10-d]imidazole derivatives with N-donor substituents

Four new 1-phenyl-1H-phenanthro[9,10-d]imidazole derivatives containing N-donor substituents at the C2 position were synthesized using simple condensation reaction. Thermal, electrochemical, spectroelectrochemical, and optical properties of synthesized compounds were investigated, while their purity was confirmed by NMR spectroscopy and HRMS. They are characterized by high thermal stability above 243 degrees C. Electrochemical measurements were carried out in dichloromethane (DCM) and THF. Quasi-reversible peaks of N2 and N5 oxidation as opposed to irreversible oxidation in THF were observed in DCM. N2 - N5 exhibit at least three well-developed absorption bands, which is typical for pi ->pi* transitions. All phenanthro[9,10-d]imidazole derivatives exhibit high photoluminescence quantum yields in the range of 34%-82% in solution. Additionally, the electroluminescent ability of the synthesized compounds was preliminarily tested.

Automated summary

In this study, four new 1-phenyl-1H-phenanthro[9,10-d]imidazole derivatives containing N-donor substituents at the C2 position were synthesized and characterized by high thermal stability and photoluminescence quantum yields. Their thermal, electrochemical, spectroelectrochemical, and optical properties were investigated. Additionally, their electroluminescent ability was preliminarily tested.