A new ruthenium（Ⅱ） complex,[Ru（bpy）2bdpq](ClO4)2,where bpy=2,2′-bipyridine,（bdpq=2-（benzoxazol-2-yl）-dipyrido） [2,3-f: 2′,3′-h]quinoxaline,was synthesized and characterized by IR,（）1H NMR,MALDI-TOF MS,and elemental analysis.The electronic absorption and emission spectral titrations with calf thymus DNA,steady-state emission quenching by [Fe（CN）6]4-,and viscosity measurements were carried out to study the binding of [Ru（bpy）2bdpq](ClO4)2 with the DNA.The results indicate that the（Ru（Ⅱ）） complex acts as a DNA intercalator with a binding constant of（1.9±0.1）×106 L/mol at 50 mmol/L NaCl,and can serve as a good "DNA molecular light switches" with a luminescence enhancement factor of 180.
