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Journal of Chemistry
Volume 2015, Article ID 439270, 10 pages
Research Article

Assignment of O–O and Mo=O Stretching Frequencies of Molybdenum/Tungsten Complexes Revisited

Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371

Received 22 December 2014; Revised 25 March 2015; Accepted 2 April 2015

Academic Editor: Arturo Espinosa Ferao

Copyright © 2015 Choon Wee Kee. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The assignment of peroxo stretching frequencies for Molybdenum and Tungsten complexes is studied by DFT and MP2 calculations. We found that M06 functional is unsuitable for assignment of Mo=O and O–O stretches in CpMo(η2-O2)OCH3 and we found that MP2 and even the def2-TZVP do not give accurate order of asymmetric and symmetric Mo=O stretching. We recommend the M06L, which is a good compromise between speed and accuracy, for works involving these complexes. For a series of ten Molybdenum and Tungsten complexes studied we found that, for Mo/W=O stretching frequencies at M06L/def2-TZVP, after scaling, a small RMSD of 15 cm−1 could be obtained. However peroxo stretching frequencies RMSD remains high at 40 cm−1 after scaling. This could potentially point out the need for reassignment of experimental peroxo frequencies in some of the works cited in this report.