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New Journal of Chemistry, vol.50, no.8, pp.3674-3693, 2026 (SCI-Expanded, Scopus)
In this study, a series of functionalized benzimidazolium salts and their PEPPSI-type Pd(ii)NHC complexes 3a–g were synthesized and characterized by FT-IR, 1H NMR and 13C NMR spectroscopy, elemental analysis, and mass spectrometry. Quantum chemistry computations at the B3LYP/6-311G(d,p)/LANL2DZ level were used to examine the molecular structure, electronic characteristics, and chemical reactivity of the ligand and its Pd complex. The new salt and PEPPSI-type Pd-NHC complex were fully characterized by spectroscopic and analytical methods. Under the optimized reaction conditions, the catalytic activity of the NHC–PEPPSI–Pd(ii) complexes was tested by direct arylation of 2-n-propylthiazole and 4,5-dimethylthiazole with various aryl halides at 120 °C for 1 h and 3 h, respectively. It was observed that the palladium complexes gave high yields and were selective at the C5 and C2-positions of heteroaryl derivatives. Complex 3f, with an NHC substituted by a 3,4,5-trimethoxybenzyl group, showed the highest conversion probably due to the flexibility, electronic and mostly steric effects of this group.