Two Cu(II)-Nitronyl Nitroxide Complexes Including Cyclic Dimer: Synthesis, Structures and Magnetic Interactions

Abstract

Using two new flexible and functional nitronyl nitroxide radicals as ligands, two copper (II) complexes {[Cu(hfac) 2 ] 3 (NITmPhO3Py) 2 } n (1) and [Cu(hfac) 2 (NIToPhO3Py)] 2 (2) (NITmPhO3Py = 2-[(3-methoxy-pyridinyl)phen-3-yl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, NIToPhO3Py = 2-[(3-methoxypyridinyl)phen-2-ly]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, hfac = hexafluoroacetylacetone), have been characterized structurally and magnetically. The X-ray crystal analyses showed that complex 1 displayed a chain polymer structure which formed with {[Cu(hfac) 2 ] 3 (NITmPhO3Py) 2 } n due to the cross-linking of two cyclic binuclear fragments {[Cu(hfac) 2 ] 2 (NITmPhO3-Py) 2 } via the bridging unit [Cu(hfac) 2 ]; complex 2 presented a binuclear cyclic structure [Cu(hfac) 2 ] 2 (NIToPhO3Py) 2 . The magnetic behaviors of the two complexes 1 and 2 have been investigated. Magnetic studies showed that antiferromagnetic interactions dominated in complex 1, while there existed ferromagnetic interactions between Cu(II) and coordinated NO group in complex 2.