Reactivity Consequences of Steric Reduction in Cyclopentadienyl Chromium β-Diketiminate Complexes

• DOI: 10.1021/om900788c
• Publication Date: 2009-12-07T06:52:53Z
• Authors: K. Cory MacLeod; Julia L. Conway; Liming Tang; Joshua J. Smith; Liam D. Corcoran; Katherine H. D. B...; Brian O. Patrick; Kevin M. Smith
• Keywords: Reactivity; Cyclopentadienyl complex; Salt metathesis reaction; Anhydrous

A series of Cr(III) half-sandwich β-diketiminate complexes, CpCr[(ArNCMe)2CH]X, X = I (2), CH3 (3), or Cl (4), were prepared. Compared to previously communicated complexes with Ar 2,6-iPr2C6H3 (Dpp, a), less sterically demanding ligands such as 2,6-Me2C6H3 (Xyl, b), 2,4,6-Me3C6H2 (Mes, c), 2,6-Et2C6H3 (Dep, d) more readily synthesized via salt metathesis reactions. Iodide compounds 2b−d prepared by oxidation the corresponding Cr(II) species CpCr[(ArNCMe)2CH] 1b−d half an equivalent iodine. The chloride CpCr[(ArNCMe)2CH]Cl 4c−d in a two-step, one-pot reaction from anhydrous CrCl3. MeMgI either iodide precursors yielded methyl CpCr[(ArNCMe)2CH](CH3) 4b−d. All paramagnetic characterized UV−visible spectroscopy and elemental analysis, structures 2b, 2c, 3b, 3c, 3d, 4c, 4d determined X-ray crystallography. Reaction iodomethane generates complexes. rate this single-electron oxidative addition was shown remain relatively invariant upon changing N-aryl substituent.