1,3-substituted-imidazo[1,5-a]pyridine: New Series of Fluorescent Derivatives

A new general synthetic method, developed both through standard and microwave heating, provides a versatile one step approach for the synthesis of multidentate nitrogen heterocyclic ligands, containing a pair of biologically relevant imidazo[1,5-a]pyridine moieties (Figure 1). These compounds show considerable optical properties, with good fluorescent emissions, moderate quantum yields and large Stokes’ shifts enabling their technological application. Figure 1. General structures of synthesized compounds The photofunctional diversity of the synthesized compounds imply that the bis(1- (pyridin-2-yl)imidazo[1,5-a]pyridin-3-yl)benzene and their derivatives can potentially be used as easily tuneable photofunctional materials and as tetradentate ligands of interest in the fields of DSCs, OLED, NLO and for pharmaceuticals applications. Figure 2. Absorption (left) and Emission spectra (right) for compounds 1–6. Moreover, quantitative yields, absence of catalysts, high accessibility and stability, ease of handling and preparation, no toxicity of reagents and derivatives render this synthetic approach particularly useful for a systematic screening and full-scale production and make the products inexpensive and affordable.