Synthesis, Characterization, and Crystal Structure of the (η5-C5Ph5)Cr(CO)3 Radical

Authors

Ray J. Hoobler
Marc A. Hutton
Mills M. Dillard
Michael Castellani, Marshall UniversityFollow
Arnold L. Rheingold
Anne L. Rieger
Philip H. Rieger
Thomas C. Richards
William E. Geiger

Document Type

Article

Publication Date

1993

Abstract

The reaction between Cr(CO)₆ and Na(C₅Ph₅ ) in refluxing diglyme yields [Na(diglyme)_3/2][(C₅Ph₅)Cr(CO)₃], 1. Metathesis of 1 with [Ph₃P=N=PPh₃ ]Cl in CH₂Cl₂ yields [Ph₃P=N=PPh₃][(C₅Ph₅)Cr(CO)₃], 2. Oxidation of 1 by AgBF4 in cold THF under an argon atmosphere produces (C₅Ph₅)Cr(CO)₃, 3. Complexes 2 and 3 form a redox pair connected by a quasireversible one-electron process, E⁰ = -0.69 V vs ferrocene in CH₂Cl₂, E₀ = -0.50 V in CH₃CN, k_s = 0.12 cm/s. ESR spectra of (C₅Ph₅)Cr(CO)₃ in toluene at 90 K gave a rhombic g-tensor with components 2.1366, 2.0224, and 1.9953, consistent with the expected low-spin d⁵ electronic configuration. The largest g-tensor component was significantly temperature dependent, suggesting an equilibrium between conformations with ²A´ and ²A˝ ground states. Crystal structures of [Ph₃P=N=PPh₃][(C₅Ph₅)Cr(CO)₃] and (C₅Ph₅)Cr(CO)₃ were obtained.

Comments

This is the authors’ peer-reviewed manuscript. The version of record is available from the publisher at http://dx.doi.org/10.1021/om00025a023. Copyright ©1992 American Chemical Society. All rights reserved.

Recommended Citation

Hoobler, R. J.; Hutton, M. A.; Dillard, M. M.; Castellani, M. P.; Rheingold, A. L.; Rieger, A. L.; Rieger, P. H.; Richards, T. C.; Geiger, W. E., Synthesis, characterization, and crystal structure of the (η5-C5Ph5) Cr (CO) 3 radical. Organometallics. 1993;12(1):116-23.