title: NMR spectroscopy and DFT calculations of a self-assembled arene ruthenium rectangle obtained from a combination of coordination and hydrogen bonds.
abstract: The hydrogen-bonded arene ruthenium metalla-rectangle, [(p-cymene)2Ru2(OO∩OO)(UPy)2]2(4+), 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(OO∩OO)Cl2 (OO∩OO = 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.
authors.affiliation: Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland.
authors.forename: Divambal
authors.initials: D
authors.lastname: Appavoo
authors.affiliation: Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland.
authors.forename: Nandhagopal
authors.initials: N
authors.lastname: Raja
authors.affiliation: Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland.
authors.forename: Robert
authors.initials: R
authors.lastname: Deschenaux
authors.affiliation: Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland and Neuchâtel Platform of Analytical Chemistry (NPAC), Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland. diego.carnevale@unine.ch bruno.therrien@unine.ch.
authors.forename: Bruno
authors.initials: B
authors.lastname: Therrien
authors.affiliation: Neuchâtel Platform of Analytical Chemistry (NPAC), Institut de Chimie, Université de Neuchâtel, Avenue de Bellevaux 51, 2000 Neuchâtel, Switzerland. diego.carnevale@unine.ch bruno.therrien@unine.ch and Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Avenue Forel 2, 1015 Lausanne, Switzerland.
authors.forename: Diego
authors.initials: D
authors.lastname: Carnevale