Applications of high-field (W-band) EPR to M-M bonded units (M = Cr, Mo): the first confirmed oxidation of a Cr2 4+ paddlewheel complex to a stable isostructural Cr2 5+ product.
The EPR spectra of [Cr(2)[(PhN)(2)CN(CH(2))(4)](4)]PF(6) and [Mo(2)(TiPB)(4)]PF(6) (TiPB = anion of 2,4,6-triisopropylbenzoic acid) at W-band are shown to have g values significantly lower than 2.00 and exhibit parallel and perpendicular components (not resolved at X-band). Therefore the unpaired electrons of the M(2)(5+) units must reside on metal-based (not ligand-based) orbitals. Thus, the chromium compound must be considered as the first confirmed oxidation product of a Cr(2)(4+) paddlewheel complex comparable to the Mo(2)(5+) compounds.
Cotton
F Albert
FA
Department of Chemistry and Laboratory for Molecular Structure and Bonding, PO Box 30012, Texas A&M University, College Station 77842-3012, USA. cotton@tamu.edu
Dalal
Naresh S
NS
Hillard
Elizabeth A
EA
Huang
Penglin
P
Murillo
Carlos A
CA
Ramsey
Chris M
CM