A Caltech Library Service

Exploring secondary-sphere interactions in Fe–N_xH_y complexes relevant to N_2 fixation

Creutz, Sidney E. and Peters, Jonas C. (2017) Exploring secondary-sphere interactions in Fe–N_xH_y complexes relevant to N_2 fixation. Chemical Science, 8 (3). pp. 2321-2328. ISSN 2041-6520. PMCID PMC5363375. doi:10.1039/c6sc04805f.

[img] PDF - Published Version
Creative Commons Attribution.

[img] PDF - Supplemental Material
Creative Commons Attribution.

[img] Crystallographic Info File (CIF) - Supplemental Material
Creative Commons Attribution.


Use this Persistent URL to link to this item:


Hydrogen bonding and other types of secondary-sphere interactions are ubiquitous in metalloenzyme active sites and are critical to the transformations they mediate. Exploiting secondary sphere interactions in synthetic catalysts to study the role(s) they might play in biological systems, and to develop increasingly efficient catalysts, is an important challenge. Whereas model studies in this broad context are increasingly abundant, as yet there has been relatively little progress in the area of synthetic catalysts for nitrogen fixation that incorporate secondary sphere design elements. Herein we present our first study of Fe–NxHy complexes supported by new tris(phosphine)silyl ligands, abbreviated as [SiP^(Nme_3)] and [SiP^(iPr_2)P^(Nme)], that incorporate remote tertiary amine hydrogen-bond acceptors within a tertiary phosphine/amine 6-membered ring. These remote amine sites facilitate hydrogen-bonding interactions via a boat conformation of the 6-membered ring when certain nitrogenous substrates (e.g., NH_3 and N_2H_4) are coordinated to the apical site of a trigonal bipyramidal iron complex, and adopt a chair conformation when no H-bonding is possible (e.g., N_2). Countercation binding at the cyclic amine is also observed for anionic {Fe–N_2}− complexes. Reactivity studies in the presence of proton/electron sources show that the incorporated amine functionality leads to rapid generation of catalytically inactive Fe–H species, thereby substantiating a hydride termination pathway that we have previously proposed deactivates catalysts of the type [EP^R_3]FeN_2 (E = Si, C).

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Peters, Jonas C.0000-0002-6610-4414
Alternate Title:Exploring secondary-sphere interactions in Fe–NxHy complexes relevant to N2 fixation
Additional Information:© 2016 The Royal Society of Chemistry. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. Received 31st October 2016; Accepted 7th December 2016; First published online 08 Dec 2016. This work was supported by the NIH (GM 070757) and the Gordon and Betty Moore Foundation. Larry Henling and Mike Takase are thanked for crystallographic assistance.
Funding AgencyGrant Number
NIHGM 070757
Gordon and Betty Moore FoundationUNSPECIFIED
Issue or Number:3
PubMed Central ID:PMC5363375
Record Number:CaltechAUTHORS:20161221-100943169
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73060
Deposited By: Tony Diaz
Deposited On:21 Dec 2016 18:16
Last Modified:06 Apr 2022 19:48

Repository Staff Only: item control page