A Rhodium-Pentane Sigma-Alkane Complex: Characterization in the Solid State by Experimental and Computational Techniques

The pentane σ‐complex [Rh{Cy2P(CH2CH2)PCy2}(η2:η2‐C5H12)][BArF4] is synthesized by a solid/gas single‐crystal to single‐crystal transformation by addition of H2 to a precursor 1,3‐pentadiene complex. Characterization by low temperature single‐crystal X‐ray diffraction (150 K) and SSNMR spectroscopy (158 K) reveals coordination through two Rh⋅⋅⋅H−C interactions in the 2,4‐positions of the linear alkane. Periodic DFT calculations and molecular dynamics on the structure in the solid state provide insight into the experimentally observed Rh⋅⋅⋅H−C interaction, the extended environment in the crystal lattice and a temperature‐dependent pentane rearrangement implicated by the SSNMR data. Pentane takes a walk: The pentane sigma complex [Rh{Cy2P(CH2CH2)PCy2}(η2:η2‐C5H12)][BArF4] can be synthesized by a solid/gas single‐crystal to single‐crystal transformation. Periodic DFT calculations, molecular dynamics, and NMR spectroscopy provided insights into the fluxional processes occurring in the solid state.