CaltechAUTHORS
  A Caltech Library Service

Redox-Catalyzed Binding of Dinitrogen by Molybdenum N-tert-Hydrocarbylanilide Complexes: Implications for Dinitrogen Functionalization and Reductive Cleavage

Peters, Jonas C. and Cherry, John-Paul F. and Thomas, J. Christopher and Baraldo, Luis and Mindiola, Daniel J. and Davis, William M. and Cummins, Christopher C. (1999) Redox-Catalyzed Binding of Dinitrogen by Molybdenum N-tert-Hydrocarbylanilide Complexes: Implications for Dinitrogen Functionalization and Reductive Cleavage. Journal of the American Chemical Society, 121 (43). pp. 10053-10067. ISSN 0002-7863. doi:10.1021/ja991435t. https://resolver.caltech.edu/CaltechAUTHORS:20141210-094058286

[img]
Preview
PDF (Supporting Information) - Supplemental Material
See Usage Policy.

1MB
[img]
Preview
PDF (Supporting Information) - Supplemental Material
See Usage Policy.

217kB

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20141210-094058286

Abstract

The splitting of dinitrogen (1 atm, THF, 25 °C) by Mo(N[R]Ar)_3 (R = C(CD_3)_2CH_3, Ar = 3,5-C_6H_3Me_2) giving 2 equiv of nitride N⋮Mo(N[R]Ar)3 is found to be accelerated in the presence of sodium amalgam. Careful control of the Mo(N[R]Ar)_3 concentration led to the isolation and characterization of the anionic dinitrogen complex, [(THF)xNa][(N_2)Mo(N[R]Ar)_3], where x is from 0 to 3. Via electrochemical experiments and synthetic studies, [(THF)xNa][(N2)Mo(N[R]Ar)_3] is found to be a key intermediate in the acceleration of N_2 splitting by Mo(N[R]Ar)_3 in the presence of sodium amalgam. Accordingly, in the presence of an electron acceptor, [(THF)xNa][(N_2)Mo(N[R]Ar)_3] reacts with Mo(N[R]Ar)_3 to give the neutral N2-bridged complex (μ-N_2){Mo(N[R]Ar)_3}_2, which in turn splits to 2 equiv of nitride N⋮Mo(N[R]Ar)3. It is seen that the function of sodium amalgam in this system is as a redox catalyst, accelerating the conversion of Mo(N[R]Ar)_3 to (μ-N2){Mo(N[R]Ar)3}2, a dinuclear dinitrogen complex that does not lose N_2 readily. Electrochemical or chemical outer-sphere oxidation of [(THF)xNa][(N2)Mo(N[R]Ar)_3] leads to rapid N_2 evolution with regeneration of Mo(N[R]Ar)_3, presumably via the neutral mononuclear dinitrogen complex (N2)Mo(N[R]Ar)_3. In situ generated [(THF)xNa][(N_2)Mo(N[R]Ar)_3] was efficiently trapped by ClSiMe3 to give (Me3SiNN)Mo(N[R]Ar)_3. This complex underwent reaction with methyl triflate to give the dimethyl hydrazido cationic species, [(Me_2NN)Mo(N[R]Ar)_3][OTf]. The synthesis of the monomethyl complex (MeNN)Mo(N[R]Ar)_3 also was achieved. Experiments designed to trap the neutral mononuclear dinitrogen complex (N_2)Mo(N[R]Ar)_3 gave rise to efficient syntheses of heterodinuclear dinitrogen complexes including (Ph[tBu]N)3Ti(μ-N_2)Mo(N[R]Ar)_3, which also was synthesized in its ^(15)N_2-labeled form. Synthesis and characterization data for the new N-adamantyl-substituted three-coordinate molybdenum(III) complex Mo(N[Ad]Ar)_3 (Ad = 1-adamantyl, Ar = 3,5-C_6H_3Me_2) are presented. The complex is found to react with dinitrogen (1 atm, THF, 25 °C) in the presence of sodium amalgam to give the dinitrogen anion complex [(THF)xNa][(N_2)Mo(N[Ad]Ar)_3]; the synthesis does not require careful regulation of the Mo(N[Ad]Ar)_3 concentration. Indeed, under no conditions has Mo(N[Ad]Ar)_3 been observed to split dinitrogen or to give rise to a dinuclear μ-N_2 complex; this striking contrast with the reactivity of Mo(N[R]Ar)_3 (R = C(CD_3)_2CH_3) is attributed to the enhanced steric protection at Mo afforded by the 1-adamantyl substituents.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ja991435tDOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja991435tPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/ja991435tPublisherSupporting Information
ORCID:
AuthorORCID
Peters, Jonas C.0000-0002-6610-4414
Additional Information:© 1999 American Chemical Society. Received May 3, 1999. For support of this work, the authors are grateful to the National Science Foundation (CAREER Award CHE-9501992), the Packard Foundation, and the Alfred P. Sloan Foundation. Additional funding for which the authors are profoundly grateful has come from the National Science Board (Alan T. Waterman Award to C.C.C., 1998).
Funders:
Funding AgencyGrant Number
NSFCHE-9501992
David and Lucile Packard FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
National Science BoardUNSPECIFIED
Issue or Number:43
DOI:10.1021/ja991435t
Record Number:CaltechAUTHORS:20141210-094058286
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141210-094058286
Official Citation:Redox-Catalyzed Binding of Dinitrogen by Molybdenum N-tert-Hydrocarbylanilide Complexes:  Implications for Dinitrogen Functionalization and Reductive Cleavage Jonas C. Peters, John-Paul F. Cherry, J. Christopher Thomas, Luis Baraldo, Daniel J. Mindiola, William M. Davis, and Christopher C. Cummins Journal of the American Chemical Society 1999 121 (43), 10053-10067
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:52537
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:10 Dec 2014 22:36
Last Modified:10 Nov 2021 19:42

Repository Staff Only: item control page