Metal ion sensing ability and photo-physical properties of 4-hydroxy-3-nitroso-2H-chromen-2-one: Interaction studies with calf thymus-DNA

4-Hydroxy-3-nitroso-2H-chromen-2-one (HNC), a coumarin derivative has been synthesized through a very simple method, and its photo-physical properties were studied. HNC is used as a simple colorimetric as well as spectrophotometric chemosensor for the detection of Fe²⁺, Co²⁺, Ni²⁺ and Cu²⁺ ions, some even by naked-eyes. This process gives a sensitive readout of chemosensor HNC within a wide range of (4.5–1219.5) × 10⁻⁷ (M) at λ_max 258 nm. HNC has greater binding and detection ability toward Fe²⁺ than that of 1,10-phenanthrolin, and it has greater binding ability for Fe²⁺ than that with Fe³⁺ also. We have also established a method for solid state sensing of iron salts by HNC. Moreover, the binding interaction of HNC with calf-thymus DNA (CT-DNA) established a groove binding mode.