The Impact of Weak CH⋅⋅⋅Rh Interactions on the Structure and Reactivity of trans‐[Rh(CO)₂(phosphine)₂]⁺: An Experimental and Theoretical Examination

Abstract

The crystal structure of the new cationic Rh(I) complex trans-[Rh(CO)(2)(L)(2)]BF(4) (L=alpha(2)-(diisopropylphosphino)isodurene) was found to exhibit a nonlinear OC-Rh-CO fragment and weak intramolecular C-H...Rh interactions. These interactions, which have also been shown to occur in solution, have been examined by density functional theory calculations and found to be inextricably linked to the presence of the distorted OC-Rh-CO fragment. This linkage has also been demonstrated by comparison with a highly similar Rh(I) complex, in which these C-H...Rh interactions are absent. Furthermore, the presence of these weak interactions has been shown to have a significant effect on the reactivity of the metal center.

Stability and Dynamic Processes in 16VE Iridium(III) Ethyl Hydride and Rhodium(I) σ-Ethane Complexes: Experimental and Computational Studies

“…The PBE0 functional was found to yield results in better agreement with experimental data than the B3LYP functional in an Ir pincer system and has been endorsed as one of the best performing functionals for late transition-metal systems . A similar basis set combined with the PBE0 functional was used to calculate weak Rh···H–C interactions in another system and in our recent study of methane binding energies . Frequency calculations were carried out on all minimum structures, and the resulting frequencies all had positive values.…”

Calix[4]arene-fused phospholes

“…The existence of a tight AB pattern may here be attributed to a strong CH...O acac interaction, as inferred from a DFT calculation. The latter calculation rules out an anagostic CH...Rh bond (although CH anagostic interactions with Rh have been reported [20] ).…”

The quest for stable σ-methane complexes: computational and experimental studies

“…The PBE0 functional was found to yield results in better agreement with experimental data than the B3LYP functional in an Ir pincer system, 63 and has been endorsed as one of the best performing functionals for late transition metal systems. 64 A similar basis set combined with the PBE0 functional was used to calculate weak RhÁ Á ÁH-C interactions in another system, 65 and in our recent study of methane binding energies. 18 For each metal-ligand combination, geometries were optimized in the gas phase for [(L)M] n+ , [(L)M(Me)(H)] n+ and the agostic complexes [(L)M(s-CH 4 )] n+ .…”