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 1 H NMR, 13 C 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 µg/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.

meta-Cyanobenzyl substituted benzimidazolium salts: Synthesis, characterization, crystal structure and carbonic anhydrase, α-glycosidase, butyrylcholinesterase, and acetylcholinesterase inhibitory properties.

meta-Cyanobenzyl-substituted N-heterocyclic carbene (NHC) precursors were synthesized by the reaction of a series of N-(alkyl)benzimidazolium with 3-bromomethyl-benzonitrile. These benzimidazolium salts were characterized by using 1 H NMR, 13 C NMR, FTIR spectroscopy, and elemental analysis techniques. The molecular and crystal structures of 2f and 2g complexes were obtained by using the single-crystal X-ray diffraction method. The derivatives of these novel NHC precursors were effective inhibitors of α-glycosidase (AG), the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) with Ki values in the range of 1.01-2.12 nM for AG, 189.56-402.44 nM for hCA I, 112.50-277.37 nM for hCA II, 95.45-352.58 nM for AChE, and 132.91-571.18 nM for BChE. In the last years, inhibition of the CA enzyme has been considered as a promising factor for pharmacologic intervention in a diversity of disturbances such as obesity, glaucoma, cancer, and epilepsy.