Silylation of Iron-Bound Carbon Monoxide Affords a Terminal Fe Carbyne
- Creators
- Lee, Yunho
-
Peters, Jonas C.
Abstract
A series of monocarbonyl iron complexes in the formal oxidation states 0, +1, and +2 are accessible when supported by a tetradentate tris(phosphino)silyl ligand (SiP^(iPr)_3 = [Si(o-C_(6)H_(4)PiPr_(2))_3]−). X-ray diffraction (XRD) studies of these carbonyl complexes establish little geometrical change about the iron center as a function of oxidation state. It is possible to functionalize the terminal CO ligand of the most reduced carbonyl adduct by addition of SiMe_(3)^+ to afford a well-defined iron carbyne species, (SiP^(iPr)_3)Fe≡C—OSiMe_3. Single-crystal XRD data of this iron carbyne derivative reveal an unusually short Fe≡C—OSiMe_3 bond distance (1.671(2) Å) and a substantially elongated C−O distance (1.278(3) Å), consistent with Fe−C carbyne character. The overall trigonal bipyramidal geometry of (SiP^(iPr)_3)Fe≡C—OSiMe_3 compares well with that of the corresponding carbonyls, (SiP^(iPr)_3)Fe(CO)^−, (SiP^(iPr)_3)Fe(CO), and (SiP^(iPr)_3)Fe(CO)^+. Details regarding the electronic structure of the carbyne complex have been explored via the collection of comparative Mössbauer data for all of the complexes featured and also via DFT calculations. In sum, these data point to a strongly π-accepting Fischer-type carbyne ligand that confers stability to a low-valent iron(0) rather than high-valent iron(IV) center.
Additional Information
© 2011 American Chemical Society. Published In Issue March 30, 2011; Article ASAP March 04, 2011; Received: October 27, 2010. We acknowledge the NSF (CHE-0750234) for financial support. Dr. Neal P. Mankad provided assistance with XRD analyses, and Prof. Theodore A. Betley provided access to a Mössbauer spectrometer at Harvard University. Prof. Michael T. Green and Dr. Marc-Etienne Moret are acknowledged for insightful discussions concerning theoretical data. We also want to express gratitude to a reviewer for suggestions that improved the reported X-ray data.Attached Files
Supplemental Material - ja109678y_si_001.pdf
Supplemental Material - ja109678y_si_002.cif
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Additional details
- Eprint ID
- 24296
- Resolver ID
- CaltechAUTHORS:20110705-113849042
- NSF
- CHE-0750234
- Created
-
2011-07-05Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field