Structural analysis and third order non-linear optical investigation of red emitting luminescent aromatic nitro group appended 2-substituted Benzimidazoles

Abstract

The article reports a simple and fast green method of synthesising two aromatic nitro group appended 2-substituted Benzimidazoles from ortho-phenylenediamine, namely, 2-(2-nitrophenyl) -1 H-benzimidazole (OP2NB) and 2-(3-nitrophenyl) -1 H-benzimidazole (OP3NB), using lemon extract as green catalyst. The compounds were characterized structurally. Single crystal X-ray Diffraction of OP2NB and OP3NB were performed. OP2NB crystallises into orthorhombic crystal system and Pbca space group. OP3NB crystallises into triclinic crystal system and non-centrosymmetric P 1 space group. Absorption, emission and thermal properties were also studied. Both the 2-substituted Benzimidazoles were red emitting fluorophores. Third order Non Linear properties, investigated by Z-scan technique, indicated self-defocussing behaviour and reverse saturation absorption phenomenon.