Comparative Structural Description of Five Arene Ruthenium(Ii) Complexes with N,N- Bidentate Schiff Base Ligands and Related Complexes from Literature

Isostructurality between certain pairs of complexes A series of new half-sandwich Ru(II) complex salts of the general formula [(η6-arene)RuX(L)]PF6 (where arene = p-cymene, X = Br and L = N-tert-butyl-N-(pyridyl methylene) amine (1), N-isopropyl-2-pyridine carbaldimine (2), (2,5-dimethyl-phenyl)-pyridin-2-yl methylene amine (3), (3,5-dimethyl-phenyl)-pyridin-2-yl methylene (4) and arene = C6H6, X = I, L = (4-bromo-phenyl)-pyridin-2-yl methylene (5) have been synthesized by reacting the ruthenium arene precursors [(η6-arene)Ru(μ-X)X]2 with N,N-bidentate ligands in a 1:2 ratio. Full characterization of the complexes was accomplished using 1H and 13C NMR, elemental analyses, UV-Vis, IR and X-ray structures of all the complexes 1 - 5. The crystal structures reveal that the ruthenium centers in 1 - 5 are coordinated to the N,N-bidentate ligand in a bidentate manner, to the respective halide and to the arene ring. The whole arrangement is referred to as the three-legged piano stool, in which the N,N-bidentate ligand and the halide (Br or I) serve as the base, while the arene ring serves as the apex of the stool. A comparison to related structures from the CSD reveal isostructurality amongst certain pairs of complexes.