New morpholine-liganded palladium(II) N-heterocyclic carbene complexes: Synthesis, characterization, crystal structure, and DNA-binding studies

A series of the morpholine-liganded palladium(II) complexes (1a-e) bearing N-heterocyclic carbene (NHC) functionalized by benzonitrile were synthesized. These complexes were synthesized from (NHC)Pd(II)(pyridine) complexes (PEPPSI) and morpholine. The new complexes were fully characterized by using H-1 NMR, C-13 NMR, Fourier-transform infrared spectroscopy, and elemental analysis techniques. Single-crystal X-ray diffraction was used to determine the structure of a derivative. The DNA-binding studies of the new (NHC)Pd(II)morpholine complexes were examined using the pBR322 plasmid. The 2,4,6-trimethylbenzyl derivative compound has the most DNA binding activity. In addition, for the 3-methylbenzyl derivative compound, oxidation effects were observed at concentrations higher than 100 mu g/ml. Also, the molecular and crystal structures of the complex 3-methylbenzyl derivative compound were recorded by using a single-crystal X-ray diffraction method.