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

摘要

An NMR trans-philicity ladder was built for octahedral [Cr(CO)(5)L](-/0/+) complexes employing a C-13 NMR probe and quantified by Delta sigma C-13 NMR probe and quantified through calculation of the Delta sigma = sigma(Cr(CO)5L)-sigma(Cr(CO)5) NMR parameter employing DFT computational methods. This quantification notably retrieves the experimental trans-orienting series. The excellent linear correlations between the calculated.s NMR parameter and well established ligand electronic parameters, such as the ligand constant P-L and the ligand electrochemical parameter E-L(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)(5)L](-/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 nu(C O-trans) and nu(Cr-COtrans)vibrational frequencies, and R(Cr-COtrans)bond lengths to develop the trans-influence series and compared with the NMR trans-philicity ladder.