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

Abstract Two Dy III complexes with same N 6 O 3 donor atoms but different donor atom arrangements ‘ fac ’-[Dy III (HL DL-ala ) 3 ]·8H 2 O ( 1 ) and ‘ mer ’-[Dy III (HL DL-phe ) 3 ]·7H 2 O ( 2 ) were synthesized, where H 2 L DL-ala and H 2 L DL-phe are tridentate NNO ligands of N -[(imidazol-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 (HL D-ala ) 3 ] and ‘ fac ’-[Dy III (HL L-ala ) 3 ], while 2 consists of ‘ mer ’-[Dy III (HL D-phe ) 2 (HL L-phe )] and ‘ mer ’-[Dy III (HL D-phe )(HL L-phe ) 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 6 H 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, 6 H 15/2 ). Luminescence spectra were observed and the fine structures assigned to the 4 F 9/2  →  6 H 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 .