A New Nitronyl Nitroxide Radical as Building Blocks for a Rare <i>S</i> = 13/2 High Spin Ground State 2p-3d Complex and a 2p-3d-4f Chain

Abstract

A new nitronyl nitroxide radical L (L = 2-(4-(5-methyl-carbonyl-3-pyriyl)benzoxo)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) containing N–O groups and the pyridyl nitrogen group was designed and synthesized as a multidentate ligand to obtain compounds with interesting structures and magnetic properties from 3d or 3d-4f precursors. The reaction of Cu(hfac)2 and/or Gd(hfac)3·2H2O (hfac = hexafluoroacetylacetonate) with L resulted in a rare S = 13/2 high spin ground state CuII complex [(Cu(hfac)2)7(L)6] (1) and a CuII–GdIII chain complex [Gd(hfac)3Cu(hfac)2(L)2]n·0.5CH2Cl2 (2). Single crystal X-ray diffraction studies indicate that the N–O groups of the L radicals are all axially bound to CuII ions in complex 1, which result in the ferromagnetic exchange between CuII and radicals and an S = 13/2 high spin ground state. While adding Gd(hfac)3 units to the system of Cu(hfac)2 and L radical, a one dimension chain structure is obtained, and there are ferromagnetic GdIII-radical interactions and antiferromagnetic radical–radical coupling in the chain.