Pike, Sebastian D. and Chadwick, Mark and Rees, Nichollas H. and Scott, Mark P and Weller, Andrew S. and Krämer, Tobias and Macgregor, Stuart A. (2015) Solid-State Synthesis and Characterization of σ-Alkane Complexes, [Rh(L2)(η2,η2-C7H12)][BArF4] (L2 = Bidentate Chelating Phosphine). Journal of the American Chemical Society, 137 (2). pp. 820-833. ISSN 0002-7863

Preview

Download (3MB) | Preview

Abstract

The use of solid/gas and single-crystal to single-crystal synthetic routes is reported for the synthesis and characterization of a number of σ-alkane complexes: [Rh(R2P(CH2)nPR2)(η2,η2-C7H12)][BArF4]; R = Cy, n = 2; R = iPr, n = 2,3; Ar = 3,5-C6H3(CF3)2. These norbornane adducts are formed by simple hydrogenation of the corresponding norbornadiene precursor in the solid state. For R = Cy (n = 2), the resulting complex is remarkably stable (months at 298 K), allowing for full characterization using single-crystal X-ray diffraction. The solid-state structure shows no disorder, and the structural metrics can be accurately determined, while the 1H chemical shifts of the Rh···H–C motif can be determined using solid-state NMR spectroscopy. DFT calculations show that the bonding between the metal fragment and the alkane can be best characterized as a three-center, two-electron interaction, of which σCH → Rh donation is the major component. The other alkane complexes exhibit solid-state 31P NMR data consistent with their formation, but they are now much less persistent at 298 K and ultimately give the corresponding zwitterions in which [BArF4]− coordinates and NBA is lost. The solid-state structures, as determined by X-ray crystallography, for all these [BArF4]− adducts are reported. DFT calculations suggest that the molecular zwitterions within these structures are all significantly more stable than their corresponding σ-alkane cations, suggesting that the solid-state motif has a strong influence on their observed relative stabilities.

Item Type:	Article
Keywords:	Solid-State Synthesis; Characterization; σ-Alkane Complexes; [Rh(L2)(η2,η2-C7H12)][BArF4]; L2 = Bidentate Chelating Phosphine;
Academic Unit:	Faculty of Science and Engineering > Chemistry Faculty of Science and Engineering > Research Institutes > Hamilton Institute
Item ID:	15497
Identification Number:	https://doi.org/10.1021/ja510437p
Depositing User:	Tobias Kraemer
Date Deposited:	15 Feb 2022 12:27
Journal or Publication Title:	Journal of the American Chemical Society
Publisher:	American Chemical Society
Refereed:	Yes
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

Repository Staff Only(login required)

Item control page

Downloads

Origin of downloads