Fe–N_2/CO complexes that model a possible role for the interstitial C atom of FeMo-cofactor (FeMoco)
- Creators
- Rittle, Jonathan
- Peters, Jonas C.
Abstract
We report here a series of four- and five-coordinate Fe model complexes that feature an axial tri(silyl)methyl ligand positioned trans to a substrate-binding site. This arrangement is used to crudely model a single-belt Fe site of the FeMo-cofactor that might bind N_2 at a position trans to the interstitial C atom. Reduction of a trigonal pyramidal Fe(I) complex leads to uptake of N_2 and subsequent functionalization furnishes an open-shell Fe–diazenido complex. A related series of five-coordinate Fe–CO complexes stable across three redox states is also described. Spectroscopic, crystallographic, and Density Functional Theory (DFT) studies of these complexes suggest that a decrease in the covalency of the Fe–C_alkyl interaction occurs upon reduction and substrate binding. This leads to unusually long Fe–C_alkyl bond distances that reflect an ionic Fe–C bond. The data presented are contextualized in support of a hypothesis wherein modulation of a belt Fe–C interaction in the FeMo-cofactor facilitates substrate binding and reduction.
Additional Information
© 2013 National Academy of Sciences. Edited by Douglas C. Rees, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, and approved August 6, 2013 (received for review May 29, 2013). We thank Larry Henling and Charlene Tsay for crystallographic assistance as well as Dr. Angelo di Bilio for assistance with EPR measurements. This work was supported by the National Institutes of Health (GM 070757) and the Gordon and Betty Moore Foundation. J.R. was supported by a National Science Foundation graduate fellowship. Author contributions: J.R. and J.C.P. designed research; J.R. performed research; J.R. and J.C.P. analyzed data; and J.R. and J.C.P. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission. Data deposition: The atomic coordinates have been deposited in the Cambridge Structural Database, Cambridge Crystallographic Data Centre, Cambridge CB2 1EZ, United Kingdom (CSD reference nos. 909104–909108, 941163, and 941164).Attached Files
Published - PNAS-2013-Rittle-15898-903.pdf
Supplemental Material - sapp.pdf
Files
Name | Size | Download all |
---|---|---|
md5:ed1580c6ddd1428d31ef4834b0c3f66b
|
955.5 kB | Preview Download |
md5:62b07bddbc5d993abc043c9a068a3588
|
850.3 kB | Preview Download |
Additional details
- PMCID
- PMC3791750
- Eprint ID
- 42045
- Resolver ID
- CaltechAUTHORS:20131024-101957270
- GM 070757
- NIH
- Gordon and Betty Moore Foundation
- NSF Graduate Research Fellowship
- Created
-
2013-10-24Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field