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

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 ·2H 2 O (hfac = hexafluoroacetylacetonate) with L resulted in a rare S = 13/2 high spin ground state Cu II complex [(Cu(hfac) 2 ) 7 (L) 6 ] ( 1 ) and a Cu II –Gd III chain complex [Gd(hfac) 3 Cu(hfac) 2 (L) 2 ] n ·0.5CH 2 Cl 2 ( 2 ). Single crystal X-ray diffraction studies indicate that the N–O groups of the L radicals are all axially bound to Cu II ions in complex 1, which result in the ferromagnetic exchange between Cu II 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 Gd III -radical interactions and antiferromagnetic radical–radical coupling in the chain.