Selectivity and competition between N–H and C–H bond activation using an organoplatinum (II) complex

Abstract

Number: 97012633 and 990144222-(2 0 -Pyridyl)benzimidazole (Hpbz), containing both C-H and N-H bonds available for activation, has been investigated to elucidate which bond is activated upon coordination to the Pt(II) precursor complex (PtMe 2 (DMSO) 2 ), 1.On the basis of density functional theory (DFT), Hpbz is predicted to react with 1 through N-H bond activation of the benzimidazole ring in preference to C-H bond activation of the pyridine ring. The reasons for this difference in selectivity are discussed based on the energy barrier needed for N-H versus C-H bond activation. The DFT results are in agreement with experimental findings in which reaction of Hpbz with 1 at room temperature leads to N-H bond activation to give (PtMe(pbz-κ 2 -N,N)(DMSO)), 2. The kinetic and mechanistic study of the reaction between Hpbz and 1 shows that the reaction occurs through substitution of one DMSO by the nitrogen atom of pyridine ring of Hpbz to give (PtMe 2 (Hpbz-κ 1 N)(DMSO)), followed by N-H activation and release of methane to form 2.

Cationic N,S-chelate half-sandwich iridium complexes: synthesis, characterization, anticancer and antiplasmodial activity

“…Almost all the transition metals from group 8 to group 10 in the periodic table can be coordinated by the N-heterocyclic ligands. 1–4 Thus, transition metal complexes based on various types of N-heterocyclic ligands have been synthesized and employed in many areas, especially as efficient catalysts in diverse organic reactions, including hydrogenation, 5 oxidation, 6,7 polymerization, 8,9 cross-coupling, 10–16 amidation, 17,18 and reductive amination. 19–21 On the other hand, the prevalence of the N-heterocyclic motif in biologically active molecules has encouraged systematic explorations of such types of compounds.…”