Complexes of Mn with exclusively O-donor ligands are quite rare. Herein are five new Mn complexes supported by perfluoropinacolate (pinF) 2– or perfluoro-tert-butoxide (OC4F9) 1– ligands: Me4NMn (OH2) (pinF) 2·MeOH·H2O, 1·MeOH·H2O; K (18C6) Mn (THF) (pinF) 2·2 THF, 2·2 THF; K4Mn2 (μ2-CO3) (pinF) 4·4 H2O· MTBE (methyl t-butyl ether), 3·4 H2O· MTBE; K2Mn (O2CtBu) (pinF) 2·2 MTBE, 4·2 MTBE; K2Mn (O2CH) (pinF) 2·MTBE, 5·2 MTBE; and K (18C6) Mn (OC4F9) 3, 6. These compounds have been characterized by UV–vis spectroscopy, the Evans method for magnetic susceptibility, and SCXRD. Compounds 1–3 and 5 have been characterized by high-field EPR (HFEPR), along with the previously reported KMn (OH2) (pinF) 2, 7, K2Mn (OAc) (pinF) 2, 8, and K (18C6) Mn (pinF) 2, 10. Complex 3 was characterized by variable-temperature magnetic susceptibility (SQUID) measurements. Complex 4 is formed from the nucleophilic attack of the previously reported Mn (III) OH complex K2Mn (OH) (pinF) 2·3 MTBE, 9, on pivaloyl chloride (tBuC (O) Cl). This reactivity represents the first example of a nucleophilic attack by a structurally characterized Mn (III) OH complex. Electronic structure calculations corroborate the high-spin assignments for Mn (III) complexes 2, 5, 7–10, and were used to assign transitions in each electronic absorption spectrum. Excellently resolved HFEPR spectra were observed for 2, and 5 - 10, allowing accurate determination of the spin Hamiltonian parameters. Crystallographically independent molecules could be resolved in 7 and 8. Solvent loss in powder samples of 2 and 5 was evident in HFEPR.
Moore et al. (Mon,) studied this question.