Abstract
Two new complexes, [Co(L)2]Cl·(MeOH)2 (1) and [Ni(L)2]4·EtOH (2) (L = (E)-2-(amino((pyridin-2-ylmethylene)amino)methylene)maleonitrile), were synthesized and characterized by X-ray crystallography, IR, UV, and fluorescence spectroscopy. According to X-ray crystallographic studies, each metal was six-coordinate with six nitrogens from two ligands. Both complexes form two-dimensional supramolecular networks via hydrogen bonding and π–π interactions. Ultraviolet and visible spectra showed that absorptions arise from π–π ∗, MLCT, and d–d electron transitions. Fluorescence spectroscopy revealed moderate intercalative binding of these two complexes with EB–DNA, with apparent binding constant (K app) values of 9.14 × 105 and 3.20 × 105 M−1 for Co(III) and Ni(II) complexes, respectively. UV–visible absorption spectra showed that the absorption of DNA at 260 nm was quenched for 2 but quenched then improved for 1 with addition of complexes, tentatively attributed to the effect of the combined intercalative binding and electrostatic interaction for 1.
Acknowledgement
This work was supported by National Natural Science Foundation of China (No. 20971099).
Notes
These authors contributed equally to this work.