Slow magnetization dynamics in a six-coordinate Fe( ii )–radical complex Article - Avril 2019

Carolyn Michalowicz, Michelle Mills, Ellen Song, Dmitriy Soldatov, Paul Boyle, Mathieu Rouzieres, Rodolphe Clérac, Kathryn Preuss

Carolyn Michalowicz, Michelle Mills, Ellen Song, Dmitriy Soldatov, Paul Boyle, Mathieu Rouzieres, Rodolphe Clérac, Kathryn Preuss, « Slow magnetization dynamics in a six-coordinate Fe( ii )–radical complex  », Dalton Transactions, avril 2019, pp. 4514-4519. ISSN 1477-9226

Abstract

A new paramagnetic ligand, betaDTDA, and its coordination complex with Fe(hfac)2 are reported (betaDTDA = 4-(benzothiazol-2’-yl)-1,2,3,5-dithiadiazolyl ; hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-). The neutral radical betaDTDA is the first dithiadiazolyl ligand designed to include an electropositive sulphur moiety outside the thiazyl heterocycle, increasing the capacity for supramolecular, structuredirecting electrostatic contacts and enabling new pathways for magnetic exchange. The Fe (hfac)2(betaDTDA) complex is composed of a hs-Fe(II) center with the three bidentate ligands arranged about the ion in a distorted octahedral 6-coordinate environment. The magnetic properties of crystalline Fe(hfac)2(betaDTDA) are consistent with strong antiferromagnetic (AF) coupling between the metal and ligand moments, giving rise to a well-defined Stotal = 3/2 ground state that is the only thermally populated state below 40 K. Below 4 K, this complex exhibits slow relaxation of the magnetization detected by ac susceptibility measurements consistent with a single-molecule magnet (SMM) behaviour.

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