107883-46-5Relevant articles and documents
Temperature-dependent elongation of the H–H bond in dihydrogen complexes of Ru(II) bearing an NHC ligand: Effect of the NHC and trans ligands
Mala, Deep,Jagirdar, Balaji R.,Patil, Yogesh P.,Nethaji, Munirathinam
, p. 411 - 424 (2018/09/11)
Ruthenium hydride complexes bearing an N-heterocyclic carbene ligand [RuHCl(CO)(IMes)(PPh3)(L/L′)] (L = py, 2; 4Mepy, 3; L′ = MeCN, 4; Me3CCN, 5) have been synthesized in high-yields via reaction of [RuHCl(CO)(IMes)(PPh3)] (1) with pyridyl ligands L (L = py and 4Mepy) or nitrile ligands L′ (L′ = MeCN and Me3CCN). The ligands L/L′ are labile in all the ruthenium hydride complexes; they can be easily replaced by Lewis bases. The X-ray structures of complexes 2 and 3 show intramolecular π-π interactions between the aromatic ring of PPh3, IMes, and pyridyl ligands. The protonation reaction of 2–5 gives the corresponding dihydrogen complexes of the type [RuCl(η2-H2)(CO)(IMes)(PPh3)(L/L′)][OTf] complexes (L = py, 6; 4Mepy, 7; L′ = MeCN, 8; Me3CCN, 9). In all the dihydrogen complexes, H–H bond distances of η2-H2 ligand is temperature-dependent: 0.98 ? to 0.93 ? in the temperature range of 183–233 K. Attempts to synthesize analogous ruthenium hydride complexes bearing phosphine ligands resulted in a mixture of cis and trans-[RuHCl(CO)(PPh3)2(L)] [L = py, 10/11 (transHCl/cisHCl); 4Mepy, 12/13 (transHCl/cisHCl)] complexes. A comparative study has been done to get an insight into the temperature-dependent H–H bond distances in complexes 6–8 by synthesizing analogous ruthenium dihydrogen complexes, [RuCl(η2-H2)(CO)(PPh3)2(L)](OTf) (L = py, 15; 4Mepy, 17). All the complexes have been characterized using NMR spectroscopy. The X-ray crystal structures of complexes 2, 3, and 12 have also been determined.
