Ruthenium Complexes Bearing alpha-Diimine Ligands and Their Catalytic Applications in N-Alkylation of Amines, alpha-Alkylation of Ketones, and beta-Alkylation of Secondary Alcohols

New Ru(II) complexes encompassing alpha-diimine ligands were synthesized by reacting ruthenium precursors with alpha-diimine hydrazones. The new ligands and Ru(II) complexes were analyzed by analytical and various spectroscopic methods. The molecular structures of L-1 and complexes 1, 3, and 4 were determined by single-crystal XRD studies. The results reveal a distorted octahedral geometry around the Ru(II) ion for all complexes. Moreover, the new ruthenium complexes show efficient catalytic activity toward the C-N and C-C coupling reaction involving alcohols. Particularly, complex 3 demonstrates effective conversion in N-alkylation of aromatic amines, alpha-alkylation of ketones, and beta-alkylation of alcohols.