Helices of ruthenium complexes involving pyridyl–azine ligands: synthesis, spectral and structural aspects

Abstract

New cationic complexes [Ru(η⁵-C₅H₅)(EPh₃)(L)]BF₄ [L=pyridine-2-carbaldehyde azine (paa); E=P, 1; E=As, 2; E=Sb, 3] and κ¹ bonded dppm complexes [Ru(η⁵-C₅H₅)(κ¹-dppm)(L)]BF₄ [L=paa 4; L=p-phenylene-bis(picoline)aldimine (pbp) 5] containing both group V donor and pyridyl–azine ligand are reported. The complexes were fully characterized by analytical and spectral studies. ³¹P NMR spectral studies suggested coordination of dppm in the complexes 4 and 5 in κ¹-manner, which was further, confirmed by structural studies on the representative complex 4. Weak interaction studies revealed that inter- and intramolecular C–H⋯X (X=O, F, Cl, π) and π–π interactions in the complexes 1 and 4 lead to helical structures.