Design, Syntheses And Magnetic Properties Of Complexes Based On New Radicals-3d Or 4f Metal Ions And The Study Of New Single-molecule Magnets

The syntheses of single-molecule magnets (SMMs) and single-chain magnets (SCMs) have attracted much interest in the fields of molecule-based magnetism and solid-state physics. Since the discovery of the first SCM based on nitronyl nitroxide radicals and metal hexafluoroacetylacetonate (hfac) salts by D. Gatteschi's group, much work has been done on studying the magnetic complexes containing nitronyl nitroxide radicals with the pursuits of SMMs and SCMs. In this paper, twenty-four kinds of new 2p-4f complexes and four kinds of new 3d-4f complexes have been synthesized by using NITPhOEt and NITPhOCH2Ph nitronyl nitroxide radicals. Their structures have been determined by X-ray crystallographic methods and characterized by element analyses, IR spectra, UV-visible spectra, ESR spectra and variable-temperature magnetic susceptibility.The complex [Tb(hfac)3(NITPhOEt)2] (1) shows the SMM behavior, to our knowledge it is the first example of mononuclear lanthanide-radical based SMM bridged only through N-O, and it is also one of the seldom examples based on rare earth-radical SMM. Two ferromagnetic Radical-Gd(III)-Radical complexes were reported in this paper. To evaluate the magnetic interaction between radicals within Radical-Gd(III)-Radical complexes more exactly, the magnetic interaction between radicals within isomorphic complex Radical-Lu(III)-Radical has been analyzed firstly. The complexes [Ce(hfac)3(NITPhOEt)]n (3) and [Pr(hfac)3(NITPhOEt)]n (4) consist of alternating Ce(hfac)3 or Pr(hfac)3 and NITPhOEt radical in 1-D chain, complex [(Cu(hfac)2)3(NITPhOEt)2] (25) consists of three Cu(hfac)2 and two NITPhOEt, and other twenty-five complexes all consist of isolated Radical-Ln(III)-Radical molecular.To study how the radicals influence the structure of the complexes, we synthesized three kinds of new 2p-3d complexes by using NITPyOMe, which contains another coordinated N atoms. Their structures have been determined and characterized by variable-temperature magnetic susceptibility.