676592-55-5Relevant academic research and scientific papers
Multifunctional Behavior by a Bis-(phosphinimino)methanide Ligand: η2-vs η3-coordination vs Bronsted Basicity
Bibal, Christine,Pink, Maren,Smurnyy, Yegor D.,Tomaszewski, John,Caulton, Kenneth G.
, p. 2312 - 2313 (2004)
The reaction of [(Cymene)RuCl2]2 with the chelate LiHC(PPh2NPh)2 occurs to remove both chloride ligands, to furnish a cationic Ru(II) complex with the monoanionic ligand bound η3, through two N and an sp3 carbon. This cation is also produced from the conjugate acid of the ligand H2C(PPh2NPh)2 because this molecule can serve as a Bronsted base, to deprotonate the acidic carbon of another molecule of H2C(PPh2NPh)2. DFT calculations show an energy surface where (Cymene)RuHC(PPh2NPh)2L is more stable with a Ru?CH(PPh2NPh)2 bond and with L = Cl- or MeCN not coordinated to Ru, than to an η2-HC(PPh2NPh)2 structure with coordinated L; this is tested experimentally. The greater tendency for this ligand to be coordinated η3 vs analogous diketiminates is discussed. The nucleophilicity of Cγ in structure 1, vs that of donors L = Cl- or MeCN, is evaluated to understand the preference of the bis(phosphinimino)methanide to be bidentate or tridentate. Copyright
New features of bis(phosphinimine)- carbene binding to Ru II
Smurnyy, Yegor,Bibal, Christine,Pink, Maren,Caulton, Kenneth G.
, p. 3849 - 3855 (2008/10/09)
Analysis of the results of DFT(PBE) calculations on a variety of species containing a RuC-(PPh2NPh)2 subunit led to the proposal that this should be considered as an example where an Ru/C single bond is present, which leaves a stereochemically active lone pair on the carbene carbon and thus a pyramidal, quasi-sp3 hybridization for carbon. General applications of this idea are discussed, the possible protonation of this carbon lone pair is described, and a DFT(PBE) geometry optimization of the two species (Cl)nRuHC(PPh 2NPh)2(1-n)+ with n = 0, 1 reveals a potential for oxidative addition of the P/N bond of this ligand to Ru, to generate an RuNPh moiety. The crystal structure of the triflate (CF3SO 3-) salt of the C-protonated species (Cymene) Ru[H*C(PPh2NPh]2]+ shows that H* hydrogen bonds to triflate.
