Fluorescence and DNA-binding spectral studies of neodymium(III) complex containing 2,2′-bipyridine, [Nd(bpy)2Cl3•OH2]

The interaction of [Nd(bpy)(2)Cl-3 center dot OH2], where bipy is 2,2'-bipyridine, with DNA has been studied by absorption, emission, and viscosity measurements. [Nd(bpy)(2)Cl3 center dot OH2] showed absorption decreasing in charge transfer band with increasing of DNA. The binding constant, K-b has been determined by absorption measurement and found to be (1.5 +/- 0.1) x 10(5) M-1. The fluorescent of[Nd(bpy)(2)Cl-3 center dot OH2] has been investigated in detail. The interaction was also studied by fluorescence quenching technique. The results of fluorescence titration revealed that DNA had the strong ability to quenching the intrinsic fluorescence of Nd(III) complex at 327 nm. The binding site number n, apparent binding constant K-b and the Stern-Volmer quenching constant K-SV have been determined. Thermodynamic parameters have been calculated according to relevant fluorescent data and Van't Hoff equation. Characterization of bonding mode has been studied. The results suggested that the major interaction mode between [Nd(bPY)(2)Cl-3 center dot OH2] and DNA was groove binding. (C) 2009 Elsevier B.V. All rights reserved.