71411-15-9Relevant academic research and scientific papers
Phosphorus-31 NMR study of rhodium poly(phosphine) nitrosyl complexes. An attempt to prepare the elusive example of a planar {MNO}10 complex containing a bent nitrosyl ligand
Mazanec, Terry J.,Tau, Kwoliang D.,Meek, Devon W.
, p. 85 - 91 (2008/10/08)
Displacement of triphenylphosphine from Rh(PPh3)3NO by chelating bis(phosphine), tris(phosphine), and tetrakis(phosphine) ligands produces a series of new complexes of formulation RhLn(PPh3)3-nNO, where Ln corresponds to a poly(phosphine) ligand containing n phosphine groups. On the basis of phosphorus-31 NMR spectroscopy, all of these complexes have a pseudotetrahedral inner coordination sphere around rhodium. They appear to have nearly linear Rh-N-O linkages. The potentially tridentate ligand Ph2PCH2CH2CH2P(Ph)CH 2CH2CH2NMe2 displaces only two triphenylphosphine ligands from Rh(PPh3)3NO, as the -NMe2 group remains nonbonded in solution. At -40°C the potentially tetradentate ligand P(CH2CH2PPh2)3 functions as a tridentate in which one of the terminal -PPh2 groups is nonbonded. However, at higher temperatures, all three terminal diphenylphosphino groups undergo exchange. A line-shape analysis of the 31P NMR spectra gives ΔG? = 8.6 kcal/mol and ΔS? = -17.2 eu which indicates that the exchange occurs via an associative mechanism and suggests the transient formation of the supersaturated 20-electron, five-coordinate complex Rh(PP3)NO. Complexes of the type Rh(R2P(CH2)nPRR′)(PPh3)NO are chiral at the rhodium atom. Use of a diphosphine ligand containing a chiral substituent on one phosphorus atom (i.e., (2-(diphenylphosphino)ethyl)neomenthylphenylphosphine) shows that the phosphorus resonance is affected more by the chiral carbon substituent than by the chiral nature of the rhodium atom. Trends among the phosphorus-rhodium and phosphorus-phosphorus coupling constants are discussed in relation to the oxidation state of rhodium and the number and size of any chelate rings in the RhLn(PPh3)3-nNO complexes.
