Abstract:
A series of novel benzimidazolium salts 2 and their new air and moisture stable PEPPSI type N-heterocyclic carbene palladium(II) complexes (PEPPSI: pyridine-enhanced pre-catalyst preparation, stabilisation, and initiation), were synthesized and characterized by means of H-1 and C-13{1H} NMR, FTIR spectroscopic methods and elemental analysis was employed to catalyze the Mizoroki-Heck cross-coupling reactions of aryl bromides with styrene in water. To the best of our knowledge, this is the first report where a Pd-PEPPSI catalyst was successfully employed in aqueous-phase Mizoroki-Heck reaction. Good to excellent yields of cross-coupling products were obtained with a range of representative aryl bromides under relatively mild conditions. Moreever the antimicrobial activity of the PEPPSI type N-heterocyclic carbene palladium(II) complexes 3a-e varies with the nature of the ligands. Also, the IC50 values of both, complexes (3a-e) have been determined. In addition, the new PEPPSI type N-heterocyclic carbene palladium(II) complexes were screened for their cytotoxic activities. Complex 3b exhibited the highest antitumor effect with IC50 values 0.63 mu g/mL and against MCF-7. (C) 2021 Elsevier B.V. All rights reserved.