Luminescent DyIII single ion magnets with same N6O3 donor atoms but different donor atom arrangements, ‘fac’-[DyIII(HLDL-ala)3]·8H2O and ‘mer’-[DyIII(HLDL-phe)3]·7H2O

Two Dym complexes with same N603 donor atoms but different donor atom arrangements 'fac'-[Dy-III(HLDL-ala)(3)]center dot 8H(2)O (1) and 'mer'-[Dy-III(HLDL-phe)(3)]center dot 7H(2)O (2) were synthesized, where H2LDL-ala and H2LDL-phe are tridentate NNO ligands of N-Rimidazol-4-yl)methylidene]-DL-alanine and N-[(imidazol-4-yl)methylidene]-DL-phenylalanine, respectively. Each Dy-III ion is coordinated by three mono-deprotonated mono-negative NNO tridentate ligands to form a nona-coordination geometry of a tricapped trigonal prism (TTP). 1 consists of enantiomers 'fac'-[Dy-III(HLD-ala)(3)], and 'fac'-[Dy-III(HLL-ala)(3)], while 2 consists of 'mer'-[Dy-III(HLD-phe)(2)(HLL-phe)] and 'mer'-[Dy-III(HLD-phe)(HLL-ala)(2)]. The temperature dependence of the magnetic susceptibilities and field-dependence of the magnetization of two complexes showed the different magnetic profiles and the Stark splitting of the ground state H-6(15/2) due to the crystal field effect on Dy-III ion (4f(9), J = 15/2, S = 5/2, L = 5, g(J) = 4/3, H-6(15/2)). Luminescence spectra were observed and the fine structures assigned to the F-4(9/2) -> H-6(15/2) transitions are partially observed. 1 and 2 showed an out-of phase signal with frequency-dependence in alternating current (ac) susceptibility under a dc bias field of 1000 Oe, indicative of field induced single ion magnet (SIM). The ac magnetic susceptibilities under 1000 Oe dc field of 2 showed the maximum peaks at the higher temperature than those of 1, indicating that the energy barrier of 2 is larger than that of 1.