Syntheses, crystal structures and magnetic properties of a new nitronyl nitroxide NIT2-bithph and its manganese(II) compound [Mn(hfac) 2(IMHBithph)] 2·(NIT2-bithph)(C 6H 14)

Abstract

A new nitronyl nitroxide NIT2-bithph ( 1) and its manganese(II) compound [Mn(hfac) 2(IMHBithph)] 2·(NIT2-bithph)(C 6H 14) ( 2) (hfac = hexafluoroacetylacetonate; NIT2-bithph = 4,4,5,5-tetramethyl-2-(bithiophenal-2-yl)imidazoline-1-oxyl-3-oxide; IMHBithph = 1-hydroxy-2-bithiophenal-4,4,5,5-tetramethyl-4,5-dihydro- 1H-imidazole) have been synthesized and structurally characterized by X-ray diffraction methods. The units of compound 1 were connected as one-dimensional chain by the intermolecular hydrogen bonds which afford an intermolecular antiferromagnetic interaction between nitronyl nitroxide radicals within the chain ( J = −1.89 cm −1). Compound 2 resulting from the reaction of Mn(hfac) 2·2H 2O and NIT2-bithph is dinuclear and includes the reduced amidino-oxide form of NIT2-bithph, it is made up of three parts: a [Mn(hfac) 2(IMHBithph)] 2 dimer unit, an uncoordinated NIT2-bithph radical and a noncoordinated solvent molecule of hexane, the molecule of radical is hydrogen bonded to its reduced form. Two reduced IMHBithph ligands bridge the two manganese(II) ions through their amidino-oxide oxygen atoms resulting in a small intramolecular antiferromagnetic interaction between the manganese ions ( J = −1.55 cm −1).