Heterocycled triazole and azomethine substituted multifunctional graphene based hybrid ligands: color and sensor properties

Abstract

Reduced graphene oxide (rGO) was obtained from graphene oxide (GO) by hydrothermal method. In order to easily synthesize hybrid compounds (HB¹ and HB²), the carboxyl groups on the surface of rGO were converted to acyl chloride with SOCl₂ and rGO-COCl was obtained. To use in the synthesize of the hybrids, two new carboxylic acid substituted multifunctional imine compounds ({(E)-4-((2-hydroxy-4-((1-(p-tolyl)-1 H-1,2,3-triazol-4-yl)methoxy) benzylidene)amino)benzoic acid (5), (E)-4-((2-hydroxy-4-((1-(4-methoxyphenyl)-1 H-1,2,3-triazol-4-yl)methoxy)benzylidene)amino)benzoic acid (6)}) were obtained and characterized by the ¹H and ¹³C(¹H)NMR, FT-IR, MALDI-TOF-MS techniques. The hybrids were obtained from the reaction of the imine and rGO-Cl compounds and characterized by the FT-IR, UV–Vis, emission (PL), X-ray diffraction (XRD), SEM-EDX and TEM methods. The chemosensor properties of the hybrids were investigated towards some metal ions (Al³⁺, Ag⁺, Co²⁺, Cr³⁺, Cu²⁺, Fe³⁺, Hg²⁺, Mn²⁺, Ni²⁺, Zn²⁺, Cd²⁺, Pb²⁺). At the short wavelength light, HB¹ showed a blue sensor against Ag⁺, Co²⁺, Cu²⁺, Fe³⁺, Ni²⁺ and Pb²⁺ ions, dark green against Al³⁺, Zn²⁺ and Cd²⁺ ions, and purple-colored sensors against Hg²⁺ ions. HB² hybrid material exhibited sensor properties against Ag⁺, Cr³⁺, Cu²⁺, Fe³⁺, Zn²⁺ and Cd²⁺ ions. At the long wavelength light, HB¹ and HB² materials showed sensory properties against Ag⁺, Cr³⁺, Cu²⁺, Fe³⁺, Zn²⁺ and Cd²⁺ ions. The hybrid HB¹ has selective chemosensing properties against Al³⁺ and Hg²⁺ ions at the short wavelength light. In addition, the 1931 CIE (x,y) chromaticity coordinates of the hybrids and imine compounds were investigated and the x, y values of the compounds were found to be close to the National Television Standard Committee (NTSC) standard.