Synthesis, crystal structures, photoluminescence properties and DNA binding of triazine–nickel(II) complexes for DNA detection

• Triazine–nickel(II) complexes was synthesized and characterized.
• The mechanism of DNA binding and photoluminescence of the complexes were determined.
• Complexes sensitively detect DNA over a wide concentration range.
• Complex 1 can serve as optical probes for anaerobic nonaqueous solutions.

We report here the synthesis of three new nickel(II) complexes: [Ni(PzTA)2CO3]·5H2O (PzTA = 2,4-diamino-6-(2′-pyrazin)-1,3,5-triazine) in 1, [NiQ(PyTA)(H2O)2]Cl·H2O (HQ = 8-hydroxyquinoline, PyTA = 2,4-diamino-6-(2′-pyridyl)-1,3,5-triazine) in 2, [NiQ(PzTA)(H2O)2]Cl·H2O in 3, and they were characterized by UV spectroscopy, elemental analysis, molar conductivity and X-ray single crystal diffraction. Binding of the complexes to ct-DNA was investigated with electronic spectroscopy, ethidium bromide displacement from DNA, viscometry and cyclic voltammetry. The results depicted the DNA binding mode of the three complexes was intercalation, and complex 1 together with external static-electricity. Moreover, the three complexes also presented potential anti-oxidant activity. Interestingly, we found 1 was sensitive to oxygen and to the polarity of nonaqueous solvents in fluorescence spectroscopy. Fluorescence of 2 and 3 is weak in neutral aqueous solvents, but is greatly enhanced by addition of ct-DNA. Thus, 2 and 3 can be used to DNA detection as DNA fluorescence probes with a LOD of 1.61 ng mL−1, 4.90 ng mL−1 for the relative wide linear range of 0.01–20 μg mL−1, 0.02–30 μg mL−1, respectively. These findings indicate that 1 may be a potential optical probe for oxygen-free environments in nonaqueous form, while 2 and 3 were DNA-targeted probes.

Complex 2 and 3 can be used to DNA detection as DNA fluorescence probes with a LOD of 1.61 ng mL−1, 4.90 ng mL−1 for the relative wide linear range of 0.01–20 μg mL−1, 0.02–30 μg mL−1, respectively. These findings indicate 1 may be a potential optical probe for oxygen-free environments in nonaqueous form, while 2 and 3 were DNA-targeted probes.Figure optionsDownload as PowerPoint slide