CHEMISTRY Correction for “Proton transfers are key elementary steps in ethylene polymerization on isolated chromium(III) silicates,” by Murielle F. Delley, Francisco Núñez-Zarur, Matthew P. Conley, Aleix Comas-Vives, Georges Siddiqi, Sébastien Norsic, Vincent Monteil, Olga V. Safonova, and Christophe Copéret, which appeared in issue 32, August 12, 2014, of Proc Natl Acad Sci USA (111:11624–11629; first published July 7, 2014; 10.1073/pnas.1405314111).
The authors wish to note, “On page 11626, we assigned bands in the infrared spectrum at ca. 3600 cm−1 as Si(OH)Cr-R species that result from contacting [(=SiO)3Cr] with ethylene (1). A reviewer for a recently published publication by us pointed to literature showing that these bands are also present in the infrared spectrum of polyethylene (2). This finding indicates that unambiguous observation of Si-(μ−OH)-Cr species using IR spectroscopy is not possible. We thank this reviewer for directing us to the relevant literature on this topic.”
In addition, the authors would also like to remove the following footnote on page 11628, left column: “††Note that the catalyst resting states hence corresponds to structures having Si–(μ-OH)–Cr(III) units, which is consistent with the observed red shifted OH.”
1. Delley MF, et al. (2014) Proton transfers are key elementary steps in ethylene polymerization on isolated chromium(III) silicates. Proc Natl Acad Sci USA 111(32):11624–11629.
2. Conley MP, Delley MF, Núñez-Zarur F, Comas-Vives A, Copéret C (2015) Heterolytic Activation of C-H Bonds on Cr(III)-O Surface Sites Is a Key Step in Catalytic Polymerization of Ethylene and Dehydrogenation of Propane. Inorg Chem 54(11):5065–5078.