Vibrational Couplings in Hydridocarbonyl Complexes: A 2D-IR Perspective.
Ricardo J Fernández-TeránJeannette RufPeter HammPublished in: Inorganic chemistry (2020)
Hydridocarbonyl complexes, a class of industrially relevant catalysts, contain both the M-H and M-CO moieties. Here, using two-dimensional infrared spectroscopy, we examine the coupling of the typically weak M-H stretching mode and the intense M(C≡O) mode. By studying a series of Ir(I)- and Ir(III)-based hydridocarbonyl complexes, we show that the arrangement of the H and CO ligands in a trans configuration leads to strong vibrational coupling and mode delocalization. In contrast, a cis arrangement leads to no coupling, with the localized M-H mode having a much larger anharmonicity. These results highlight a promising strategy for enhancing the M-H vibration by intensity borrowing from the strong C≡O modes in a trans configuration, allowing for direct determination by infrared spectroscopy of both the oxidation (by frequency shifts) and the protonation state (via vibrational coupling) of the complex, in mechanistic studies of proton-coupled electron transfer reactions.
Keyphrases
- electron transfer
- density functional theory
- molecular dynamics simulations
- room temperature
- energy transfer
- magnetic resonance
- raman spectroscopy
- magnetic resonance imaging
- hydrogen peroxide
- high frequency
- computed tomography
- contrast enhanced
- nitric oxide
- solid phase extraction
- molecularly imprinted
- transition metal
- liquid chromatography