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Interaction of MSn (MRu, Rh, Pd) dimers with CH 2 and CF 2 : A density functional study
Author(s) -
Xavier Eder Severino,
Duarte Hélio Anderson
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10668
Subject(s) - chemistry , binding energy , density functional theory , dimer , ab initio , atom (system on chip) , transition metal , computational chemistry , metal , ab initio quantum chemistry methods , crystallography , electronic structure , catalysis , molecule , atomic physics , physics , biochemistry , organic chemistry , computer science , embedded system
The importance of Sn to improve the performance of noble metal‐based catalysts has been extensively discussed in the literature. However, a detailed discussion about the effect of Sn on the electronic structure of the metals has not been reported so far. In this work, density functional theory (DFT) calculations have been performed on the M 2 and MSn (MRu, Rh, Pd, Sn) dimers and their interaction with CH 2 and CF 2 carbenes. The electronic structure, geometry, and harmonic frequencies are reported and compared with the available experimental data and to the previous published high level ab initio and DFT calculations. The calculated values of M 2 are in good agreement with the experimental and theoretical results. The exception is the binding energy of the Sn dimer, which can be different from the experimental estimates as much as 16 kcal · mol −1 . It has been stressed that this difficulty is related to the atomic energy reference used to estimate the binding energy. Transition metal elements are still a difficult task for DFT methods. Calculations on MSnCH 2 and MSnCF 2 species with different multiplicities and conformations have been performed. Bonding analyses on the MSn metal dimers showed that carbenes prefer to adsorb in bridge sites favoring a donating/backdonating mechanism of interaction that is enhanced with the presence of the Sn atom. The MSnCH 2 binding energy is predicted to be 40% smaller than the MSnCF 2 binding energy, following the same trends observed for the first‐row transition‐metal MCH 2 and MCF 2 complexes. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 164–176, 2003