A simple quinoxaline-based highly sensitive colorimetric and ratiometric sensor, selective for nickel and effective in very high dilution

A new quinoxaline based receptor (HQNM) has been designed and synthesized which shows a remarkable color change from colorless to yellow on specific binding with nickel. The cation recognition property of the receptor is monitored by the UV–vis and 1H NMR titrations. It is observed that the receptor shows a specific selectivity toward nickel over other interfering cations. Thus, a significant bathochromic shift in UV–vis spectrum with a sharp yellow color in ‘naked-eye’ makes the receptor suitable for the easy detection of nickel ion.