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) , 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) 2 Ru 2 (OO∩OO)Cl 2 (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.

Columnar self-assembly of N,N′,N′′-trihexylbenzene-1,3,5-tricarboxamides investigated by means of NMR spectroscopy and computational methods in solution and the solid state

“…This is an invaluable tool for structural studies and may supply experimental evidence that allows discharging a structural hypothesis in favor of another. In cases where also intermolecular internuclear distances need to be taken into account, such as in dimeric structures, or when equivalent environments supply for more than one interatomic distance, such as for CH2 groups, an effective distance that takes into account all possible polarization transfer pathways may be utilized: [31,32]   16 1…”

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

“…Therefore, we used instead the following strategy to generate the tetranuclear metalla-cycles 4ae6d: Addition of the dinuclear arene ruthenium clips, (p-cymene) 2 R- [17].…”

“…Exploiting the dimeric nature of the N-L H ligands [17], a series of dinuclear arene ruthenium complexes were prepared by reacting {(p-cymene)RuCl 2 } 2 with N-L H . The dinuclear complexes {(p-cymene)RuCl 2 (N-L H )} 2 (1e3) were obtained in excellent yields and isolated as red-orange solids (Fig.…”

“…However, we have recently shown that a combination of tetradentate and monodentate ligands can also be successful in making metalla-cycles (Fig. 2), if a series of hydrogenbonds are involved between two monodentate ligands [17]. In this system, the dimeric structure of the two quadruple H-bonding units mimics a bidentate ligand, thus offering new synthetic strategies for the generation of arene ruthenium metalla-assemblies.…”

Coordination of Piano‐Stool Complexes to a Hydrogen‐Bonded Rosette‐Type Assembly

“…Until recently, these (arene)ruthenium metalla‐assemblies were held together by covalent and multiple metal‐coordination bonds . However, last year we inserted quadruple self‐complementary hydrogen‐bonding motifs to generate a new type of (arene)ruthenium metallacycle . Yet, this self‐complementary approach was somehow limiting in terms of structural diversity, and therefore, the use of hetero hydrogen‐bond‐pairing systems can, in principle, offer more possibilities.…”