Building trans-philicity (trans-effect/trans-influence) ladders for octahedral complexes by using an NMR probe.

NMR trans-philicity (trans-effect/trans-influence) ladders have been built for a broad series of octahedral [Cr(CO)5L]-/0/+ complexes (50 ligands used) by using a 13C NMR probe and quantified through calculation of the Δσ = σCr(CO)5L-σCr(CO)5 NMR parameter employing DFT computational methods. This quantification notably retrieves the experimental trans-orienting series. The excellent linear correlations between the calculated Δσ NMR parameter and well established ligand electronic parameters, such as the ligand constant PL and the ligand electrochemical parameter EL(L), that measure the ligand bonding effects in coordination and organometallic chemistry prompt us to introduce the trans-philicity concept as a unified term to cover both the kinetic trans-effect and its thermodynamic (ground state) trans-influence cousin. The trans-philicity for ligand L is defined as the strength of philicity of the coordination site in trans-position to itself. trans-Effect and trans-influence ladders have also been built for the octahedral [Cr(CO)5L]-/0/+ complexes based on the calculated intrinsic bond dissociation energy of the Cr-COtrans bond, IBDE(Cr-COtrans) to account for the trans-effect and the ν(C[triple bond, length as m-dash]Otrans) and ν(Cr-COtrans) vibrational frequencies, and R(Cr-COtrans) bond lengths to develop the trans-influence series and compared with the NMR trans-philicity ladder.