Combining coordination and hydrogen-bonds to form arene ruthenium metalla-assemblies

Three ureido-pyrimidone derivatives (N-L^H) were used to generate in combination with four dinuclear arene ruthenium clips, (p-cymene) ₂Ru₂(OO boolean AND OO)Cl₂ (OO boolean AND OO = oxalato, 2,5-dioxido-1,4-benzoquinonato, 2,5-dichloro-1,4-benzoquinonato, 5,8-dioxido-1,4-naphtoquinonato), twelve cationic arene ruthenium metalla-cycles of the general formula [(p-cymene)₂Ru₂(OO boolean AND OO)(N-L^H)₂]₂ (CF₃SO₃)₄. The ureidopyrimidone moieties are able to form strong hydrogen-bonds by self-pairing, thus giving rise to dimeric structures in solution. In addition, to better understand the behavior of the tetranuclear metallacycles in solution, the neutral dinuclear arene ruthenium ureido-pyrimidone complexes of the general formula ((p-cymene)RuCl₂(N-L^H)} ₂ were also prepared and characterized. All metalla-assemblies were studied in solution by NMR spectroscopy, confirming the high stability of the metalla- cycles and the usefulness of hydrogen-bonds in constructing supramolecular assemblies