Synthesis and Characterization of Three-Coordinate Ni(III)-Imide Complexes
Abstract
A new family of low-coordinate nickel imides supported by 1,2-bis(di-tert-butylphosphino)ethane was synthesized. Oxidation of nickel(II) complexes led to the formation of both aryl- and alkyl-substituted nickel(III)-imides, and examples of both types have been isolated and fully characterized. The aryl substituent that proved most useful in stabilizing the Ni(III)-imide moiety was the bulky 2,6-dimesitylphenyl. The two Ni(III)-imide compounds showed different variable-temperature magnetic properties but analogous EPR spectra at low temperatures. To account for this discrepancy, a low-spin/high-spin equilibrium was proposed to take place for the alkyl-substituted Ni(III)-imide complex. This proposal was supported by DFT calculations. DFT calculations also indicated that the unpaired electron is mostly localized on the imide nitrogen for the Ni(III) complexes. The results of reactions carried out in the presence of hydrogen donors supported the findings from DFT calculations that the adamantyl substituent was a significantly more reactive hydrogen-atom abstractor. Interestingly, the steric properties of the 2,6-dimesitylphenyl substituent are important not only in protecting the Ni═N core but also in favoring one rotamer of the resulting Ni(III)-imide, by locking the phenyl ring in a perpendicular orientation with respect to the NiPP plane.
Additional Information
© 2011 American Chemical Society. Published In Issue August 24, 2011; Article ASAP July 28, 2011; Received: March 19, 2011. This work was supported by the National Science Foundation through grants CHE-0615274 and CHE-0957816 (to G.L.H.), a Beckman Scholars Fellowship from the Arnold and Mabel Beckman Foundation (to J.S.A.), and a NIH postdoctoral fellowship GM-072291 (to M.P.M.).Attached Files
Supplemental Material - ja2024993_si_001.pdf
Supplemental Material - ja2024993_si_002.cif
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Additional details
- Eprint ID
- 25486
- Resolver ID
- CaltechAUTHORS:20110929-094527399
- CHE-0615274
- NSF
- CHE-0957816
- NSF
- Arnold and Mabel Beckman Foundation
- GM-072291
- NIH
- Created
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2011-10-03Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field