Green Chemiluminescence of Highly Fluorescent Symmetrical Azo-Based Luminol Derivative

Abstract

A symmetrical azo-based Luminol derivative 2 was synthesized using catalytic dehydrogenative coupling reaction procedure. This symmetrical molecule shows blue fluorescence in polar aprotic solvents (λ max = 450 nm). With an increase in aqueous content 2 was exhibiting aggregation caused fluorescence quenching (ACQ) with a red shift of 30 nm (λ max = 480 nm). Distinct emission features were observed for this molecule with a variation in the pH range. In basic medium, deprotonated form of 2 shows fluorescence quenching followed by enhancement of green chemiluminescence (λ max = 490 nm) with H 2 O 2 /Fe 3+ catalytic system. The fluorescence and chemiluminescent (CL) properties of 2 were compared with its parent luminol 1, The CL emission intensity of 2 was found to be about 16 times higher than that of 1. In addition, HOMO-LUMO energy gap for 2 was also calculated using density functional theory (DFT) studies.

Selective Synthesis and Photoluminescence Study of Pyrazolopyridopyridazine Diones and N-Aminopyrazolopyrrolopyridine Diones

“…On the other hand, the different fluorescence intensity between structural isomers 6a and 7a was also observed [45]. The aromaticity of compound 6a possessed the bathochromic shift of fluorescence maximum λmax by 12 nm and ∼4 times significant intensity in CH2Cl2 solution when compared with compound 7a (Table 2 and Figure 3) [46]. However, the intramolecular and intermolecular hydrogen bondings between the amino and carbonyl groups of N-aminopyrazolopyrrolopyridine dione 7a were formed to lead to the poor intensity in solution.…”