Résultat de la recherche
NMR spectroscopy and DFT calculations of a self-assembled arene ruthenium rectangle obtained from a combination of coordination and hydrogen bonds
The hydrogen-bonded arene ruthenium metalla-rectangle, [(p-cymene) 2Ru2(OOnOO)(UPy)2]24+ , obtained from 1-(4-oxo-6-undecyl-1,4-dihydropyrimidin-2-yl)-3-(pyridin-4- ylmethyl)urea (UPy) and the dinuclear arene ruthenium clip (p-cymene) 2Ru2(OOnOO)Cl2 (OOnOO = 2,5-dioxido-1,4- benzoquinonato), is investigated by means of solution-phase NMR spectroscopy. Rotating frame nuclear Overhauser effect measurements are used to probe the H- bond network that drives the UPy self-assembly as well as the full rectangular supramolecular system. An effective distance that takes into account both intra-and intermolecular polarization-transfer pathways is utilised for data analysis. The experimental findings are corroborated by DFT calculations of NMR parameters and internuclear distances, thus confirming the formation of a very stable tetranuclear metalla-assembly.
Combining coordination and hydrogen-bonds to form arene ruthenium metalla-assemblies
Three ureido-pyrimidone derivatives (N-LH) 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-LH)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-LH)} 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