A New Azo Dye Based Sensor for Selective and Sensitive Detection of Cu(II), Sn(II), and Al(III) Ions

In this manuscript, we report for the very first time synthesis of a new purple azo dye (E)-1-((5-methoxy thiazolo[4,5-b]pyridin-2-yl) diazenyl) naphthalen-2-ol (TPN1). TPN1 also exhibits very interesting sensing behavior and can be potentially used for highly selective and sensitive detection of Cu²⁺, Sn²⁺ and Al³⁺. The changes in the absorption properties of TPN1 in the presence of various cations were studied extensively by UV visible spectroscopy. TPN1 dye which exhibits purple color changes to blue, orange, and lavender color respectively on addition of Cu²⁺, Sn^2+, and Al³⁺ ions respectively. Notably, TPN1 reveal different color with the number of metal ions but the peak shifting could be observed only with three metal ions in solution. Addition of Cu²⁺ to TPN1 caused bathochromic shift, while in the case of Sn²⁺ and Al³⁺ a hypsochromic effect could be observed through UV-visible spectroscopy.