VIBRATIONAL SCALING FACTORS FOR Rh(I) CARBONYL COMPOUNDS IN HOMOGENEOUS CATALYSIS

Metal carbonyl complexes are an important family of catalysts in homogeneous industrial processes. Their characteristic vibrational frequencies allow in situ tracking of catalytic progress. Structural assignment of intermedi-ates is often hampered by the lack of appropriate reference compounds. The calculation of carbonyl vibrational fre-quencies from first principles provides an alternative tool to identify such reactive intermediates. Scaling factors for computed vibrational carbonyl stretching frequencies were derived from a training set of 45 Rh-carbonyl complexes using the BP86 and B3LYP functionals. The systematic scaling of the computed C=O frequencies yields accurate calculation and assignment of the experimentally obtained 𝜈(CO) values. The vibrational scaling factors can be used to identify reaction intermediates of the industrially relevant Rh-catalyzed hydroformylation reaction. The absolute error between calculated and experimental spectra was significantly reduced and the experimental spectra were as-signed successfully.