A DNA interaction study of complex 1 was examined by EB fluorescence displacement experiment. EB can be used as a probe to determine the interaction of complex with DNA as EB emits intense fluorescence in presence of DNA. If the complex can intercalate into DNA, the INK 128 of DNA accessible for EB will be reduced and therefore the fluorescence intensity of EB will be quenched. In our experiment, as described in Fig. 2 the fluorescence intensity of EB shows a remarkable decreasing trend with increasing concentration of the metal complex. This indicates that some EB molecules are free from EB-DNA after swapping with the complex which results the decrease in fluorescence intensities of EB. The emission spectra of EB bound to DNA in absence and presence of complex 1 is shown in Fig. 2. The fluorescence quenching curve of DNA-bound EB by complex 1 (inset of Fig. 2) illustrate prolactin the quenching of EB bound to DNA by complex is in good agreement with the linear Stern–Volmer equation. The KSV value for complex 1 is found to 6.64 × 104 M−1. From KSV data external binding with moderate intercalation was speculated. Similar types of observation were found with Mn–salen complexes .