Synthesis and redox reactivity of a phosphine-ligated dichromium paddlewheel

Reed J. Eisenhart, Rebecca K. Carlson, Kelsey M. Boyle, Laura Gagliardi, Connie C. Lu

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A pentadentate ligand platform, bis[2-(diisopropylphosphino-methylamino)phenyl]ether (1), abbreviated as H2(PNONP), is introduced that enables the isolation of homodinuclear chromium complexes. In a one-step metalation using Cr(III) and Cr(II) chloride reagents, the bimetallic compounds, [Cr(μ-Cl)(PNONP)]2 (2) and [Cr(PNONP)]2 (3), respectively, were synthesized. These complexes have been characterized by X-ray diffraction, NMR spectroscopy, cyclic voltammetry, magnetometry, UV-Vis-NIR spectroscopy, combustion analysis, and computational methods. Complex 3 has a reasonably short Cr-Cr bond length of 2.1342(5) Å. Quantum chemical calculations support a diradical singlet ground-state with a formal triple bond between the chromium centers. By cyclic voltammetry, 3 exhibits two reversible oxidations at E = -470 and -750 mV versus FeCp20/+. The one- and two-electron oxidized analogues, 3+ and 32+, were generated in situ via chemical oxidation using ferrocenium. Based on in situ characterization of 3+ and 32+, we hypothesize the oxidations are metal-based to yield Cr25+ and Cr26+ cores, respectively.

Original languageEnglish (US)
Pages (from-to)336-344
Number of pages9
JournalInorganica Chimica Acta
Volume424
DOIs
StatePublished - Jan 1 2015

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phosphine
phosphines
reactivity
Chromium
Oxidation
oxidation
Cyclic voltammetry
chromium
synthesis
Electrons
Bond length
Computational methods
Ground state
spectroscopy
Nuclear magnetic resonance spectroscopy
magnetic measurement
reagents
Chlorides
Ethers
ethers

Keywords

  • Dichromium
  • Dinuclear
  • Homobimetallic
  • Metal-metal multiple bond
  • Phosphine

Cite this

Synthesis and redox reactivity of a phosphine-ligated dichromium paddlewheel. / Eisenhart, Reed J.; Carlson, Rebecca K.; Boyle, Kelsey M.; Gagliardi, Laura; Lu, Connie C.

In: Inorganica Chimica Acta, Vol. 424, 01.01.2015, p. 336-344.

Research output: Contribution to journalArticle

Eisenhart, Reed J. ; Carlson, Rebecca K. ; Boyle, Kelsey M. ; Gagliardi, Laura ; Lu, Connie C. / Synthesis and redox reactivity of a phosphine-ligated dichromium paddlewheel. In: Inorganica Chimica Acta. 2015 ; Vol. 424. pp. 336-344.
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AU - Lu, Connie C.

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