Water soluble (η6-arene) ruthenium(II) complexes incorporating marine derived bioligand: Synthesis, spectral and structural studies

A series of water soluble compounds of general formula [{(η6-arene)Ru(HMP)Cl}], [η6-arene=η6-cymene (1), η6-HMB (2), η6-C6H6 (3); HMP=5-hydroxy-2-(hydroxymethyl)-4-pyrone] have been prepared by the reaction of [{(η6-arene) RuCl2}2] with HMP. The complexes 1 and 2 react with NaN3 to give in excellent yield tetra-azido complexes [{(η6-arene)Ru(μN3)N3}2] (arene=cymene 4, HMB=5) but similar reaction of complex 3 with NaN3 yielded di-azdo complex [{(η6-C6H6)Ru(μN3)Cl}2] (6). Reaction of [{(η6-arene)Ru(μN3)Cl}2] with HMP in the presence of NaOMe resulted in the formation of azido complex [{(η6-arene)Ru(HMP)N3}]. Mono and dinuclear complexes [{(η6-arene)Ru(HMP)(L1)}]+ and [{(η6-arene)Ru(HMP)}2(μL2)]2+ were also prepared by the reaction of complexes 1 and 2 with the appropriate ligand, L1 or L2 in the presence of AgBF4 (L1=PyCN, DMAP; L2=4,4′-bipy, pyrazine). The complexes are characterized on the basis of spectroscopic data and molecular structures of three representative compounds have been determined by single crystal X-ray diffraction study.