High-Accuracy Vibrational Computations for Transition-Metal Complexes Including Anharmonic Corrections: Ferrocene, Ruthenocene, and Osmocene as Test Cases

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• 作者：Camille Latouche ; Federico Palazzetti ; Dimitrios Skouteris ; Vincenzo Barone
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2014
• 出版时间：October 14, 2014
• 年：2014
• 卷：10
• 期：10
• 页码：4565-4573
• 全文大小：305K
• ISSN：1549-9626

文摘

Density functional theory calculations of infrared spectra at harmonic and anharmonic levels of theory have been carried out in order to define a reliable yet feasible strategy to perform accurate computations on metal complexes starting from metallocenes. We present different possibilities to compute with unprecedented accuracy either the ligand vibrations or vibrations where the metal atom is involved or even to obtain the entire spectrum without invoking any scaling factor. Anharmonic calculations employing second-order vibrational perturbation theory provide very good results when performed using the B3PW91 hybrid functional associated with an extended basis set and are able to reproduce quantitatively the entire spectrum of ferrocene, including the presence of overtones at 鈭?700 cm^鈥?. Furthermore, our results confirm that B3LYP is the best functional to reproduce ligand vibrations, but, unfortunately, it provides unreliable results for vibrations involving the metal atom. Conversely, the PBE0 functional gives accurate results for metal鈥搇igand vibrational frequencies, but it is quite far from the experiment for intraligand ones.