Sm 4000 8

Magnetic circular dichroism (MCD) spectra were collected on a spectropolarimeter (Jasco J-815) interfaced with a magnetocryostat (Oxford Instruments SM-4000-8) capable of horizontal fields up to 8 T. MCD spectra were collected at 2, 4, 8, and 15 K for positive and negative field strengths of 1 to 7 T in 1 T increments. All MCD samples were prepared as thin mull samples by preparing a thick paste using Fluorolube^®. Unfortunately, although prepared in an argon-filled glovebox and immediately flash-frozen in liquid nitrogen upon removal from the box, we were unable to collect MCD spectra for 3 that were not contaminated with signals associated with the Mn^IV oxidation product, [{PhB(MeIm)₃}₂Mn^IV]²⁺, which has been previously reported as the bis(triflate) salt,^{23 (link)} prepared via oxidation of a Mn^I precursor, rather than from 3. The MCD properties of [{PhB(MeIm)₃}₂Mn^IV]²⁺ are of interest in their own right and will be reported in a separate study.

¹H NMR spectra were obtained on a Bruker DRX 400 MHz NMR spectrometer. Electronic absorption spectra were recorded on a Cary 50 Bio spectrophotometer (Varian) interfaced with a Unisoku cryostat (USP-203-A). ESI-mass spectrometry experiments were performed using an LCT Primers MicroMass electrospray-ionization time-of-flight instrument. EPR spectra were collected on Bruker EMXPlus instrument with a dual mode cavity. Magnetic circular dichroism (MCD) spectra were collected on a spectropolarimeter (Jasco J-815) interfaced with a magnetocryostat (Oxford Instruments SM-4000-8) capable of horizontal fields up to 8 T.