Crystal structures and magnetic properties of nitronyl nitroxide NIT2-phtrz and its M(II) hexafluoroacetylacetonate (M = manganese, copper) complexes [M(hfac)2(NIT2-phtrz)

Abstract

M(hfac)2 (M = Mn, Cu. hfac = hexafluoroacetylacetonate) reacts with the nitronyl nitroxide radical 4,4,5,5-tetramethyl-2-(2-phenyl-1,2,3-triazole-4-yl)imidazoline-1–oxyl-3-oxide, NIT2-phtrz (L), yielding two novel complexes [Mn(hfac)2(L)] and [Cu(hfac)2(L)]. They have been structurally and magnetically characterized. Ligand L exists in a 1-D zigzag chain structure by intermolecular H-bond interactions. [Mn(hfac)2(L)] and [Cu(hfac)2(L)] have similar structures. Each M(II) atom is coordinated by one O atom and one N atom from one L ligand and four O atoms from two hfac ligands to complete a distorted octahedral coordination environment. L acts as a bidentate ligand through the triazole N1 and one oxygen atom of the nitroxide group. Ligand L exhibits weak intermolecular antiferromagnetic interactions. [Mn(hfac)2(L)] and [Cu(hfac)2(L)] exhibit strong intramolecular antiferromagnetic interactions between the M atom and L; intermolecular antiferromagnetic interactions are observed. The magnetic properties of these compounds are discussed in connection with their crystal structures. Nitronyl nitroxide ligand NIT2-phtrz and its two novel M(hfac)2 compounds have been synthesized and characterized by X-ray crystallography. The magnetic properties of three compounds are discussed in connection with their crystal structures.