An All-O-Donor Family of Mn(II) and Mn(III) Complexes with Perfluorinated Alkoxide Ligands

Résumé fourni par la source

Complexes of Mn with exclusively O-donor ligands are quite rare. Herein are five new Mn complexes supported by perfluoropinacolate (pin F ) 2– or perfluoro- tert -butoxide (OC 4 F 9 ) 1– ligands: Me 4 N[Mn(OH 2 )(pin F ) 2 ]·MeOH·H 2 O, 1 ·MeOH·H 2 O; K(18C6)[Mn(THF)(pin F ) 2 ]·2 THF, 2 ·2 THF; K 4 [Mn 2 (μ 2 -CO 3 )(pin F ) 4 ]·4 H 2 O· MTBE (methyl t-butyl ether), 3 ·4 H 2 O· MTBE; K 2 [Mn(O 2 C t Bu)(pin F ) 2 ]·2 MTBE, 4 ·2 MTBE; K 2 [Mn(O 2 CH)(pin F ) 2 ]·MTBE, 5 ·2 MTBE; and K(18C6)[Mn(OC 4 F 9 ) 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 K[Mn(OH 2 )(pin F ) 2 ], 7, K 2 [Mn(OAc)(pin F ) 2 ], 8, and K(18C6)[Mn(pin F ) 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 K 2 [Mn(OH)(pin F ) 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.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.