96377-46-7Relevant academic research and scientific papers
Synthesis, structure, and metathesis activity of ruthenium carbene complexes containing diphosphines
Nieczypor, Piotr,Van Leeuwen, Piet W.N.M.,Mol, Johannes C.,Lutz, Martin,Spek, Anthony L.
, p. 58 - 66 (2001)
A series of ruthenium benzylidene complexes containing diphosphines (xantphos, dppf, Cy2P(CH2)nPCy2 (n=5, 8)) has been prepared, either by phosphine exchange in the ruthenium carbene complex RuCl2(=CH
Modulation of σ-Alkane Interactions in [Rh(L2)(alkane)]+ Solid-State Molecular Organometallic (SMOM) Systems by Variation of the Chelating Phosphine and Alkane: Access to η2,η2-σ-Alkane Rh(I), η1-σ-Alkane Rh(III) Complexes, and Alkane Encapsulation
Martínez-Martínez, Antonio J.,Tegner, Bengt E.,McKay, Alasdair I.,Bukvic, Alexander J.,Rees, Nicholas H.,Tizzard, Graham J.,Coles, Simon J.,Warren, Mark R.,Macgregor, Stuart A.,Weller, Andrew S.
supporting information, p. 14958 - 14970 (2018/11/02)
Solid/gas single-crystal to single-crystal (SC-SC) hydrogenation of appropriate diene precursors forms the corresponding σ-alkane complexes [Rh(Cy2P(CH2)nPCy2)(L)][BArF4] (n = 3, 4) and [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(L)][BArF4] (n = 5, L = norbornane, NBA; cyclooctane, COA). Their structures, as determined by single-crystal X-ray diffraction, have cations exhibiting Rh···H-C σ-interactions which are modulated by both the chelating ligand and the identity of the alkane, while all sit in an octahedral anion microenvironment. These range from chelating η2,η2 Rh···H-C (e.g., [Rh(Cy2P(CH2)nPCy2)(η2η2-NBA)][BArF4], n = 3 and 4), through to more weakly bound η1 Rh···H-C in which C-H activation of the chelate backbone has also occurred (e.g., [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(η1-COA)][BArF4]) and ultimately to systems where the alkane is not ligated with the metal center, but sits encapsulated in the supporting anion microenvironment, [Rh(Cy2P(CH2)3PCy2)][CO?BArF4], in which the metal center instead forms two intramolecular agostic η1 Rh···H-C interactions with the phosphine cyclohexyl groups. CH2Cl2 adducts formed by displacement of the η1-alkanes in solution (n = 5; L = NBA, COA), [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(κ1-ClCH2Cl)][BArF4], are characterized crystallographically. Analyses via periodic DFT, QTAIM, NBO, and NCI calculations, alongside variable temperature solid-state NMR spectroscopy, provide snapshots marking the onset of Rh···alkane interactions along a C-H activation trajectory. These are negligible in [Rh(Cy2P(CH2)3PCy2)][CO?BArF4]; in [RhH(Cy2P(CH2)2(CH)(CH2)2PCy2)(η1-COA)][BArF4], σC-H → Rh σ-donation is supported by Rh → σ?C-H pregostic donation, and in [Rh(Cy2P(CH2)nPCy2)(η2η2-NBA)][BArF4] (n = 2-4), σ-donation dominates, supported by classical Rh(dπ) → σ?C-H π-back-donation. Dispersive interactions with the [BArF4]- anions and Cy substituents further stabilize the alkanes within the binding pocket.
