Suguru Yamauchi, Tomotaka Hashibe, Mami Murase
Jan 25, 2013
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0
Influential Citations
11
Citations
Journal
Polyhedron
Abstract
Abstract Two racemic tridentate ligands, N-[(imidazol-4-yl)methylidene]- dl -alanine (H2L dl -ala) and N-[(imidazol-4-yl)methylidene]- dl -phenylalanine (H2L dl -phe), were synthesized by the 1:1 condensation reaction of 4-formylimidazole and either of dl -alanine and dl -phenylalanine, respectively. The EuIII complexes ‘fac’-[EuIII(HL dl -ala)3]·8H2O (1) and ‘mer’-[EuIII(HL dl -phe)3]·7.75H2O (2) were synthesized by mixing the ligand and EuIII(acetate)3 n-hydrate with 3:1 M ratio in methanol and the crystal structures were determined. Compounds 1 and 2 with three tridentate ligands have ‘facial’ and ‘meridional’ geometries, respectively, while they have a tricapped trigonal prismatic (TTP) and a capped square antiprismatic (CSAP) coordination geometry, respectively. In the crystal lattice, 1 consists of enantiomers ‘fac’-[EuIII(HL d -ala)3] and ‘fac’-[EuIII(HL l -ala)3], while 2 consists of ‘mer’-[EuIII(HL d -phe)2(HL l -phe)] and ‘mer’-[EuIII(HL d -phe)(HL l -phe)2]. Compounds 1 and 2 displayed sharp emission bands based on the f−f transitions by excitation and showed a different emission pattern due to their ‘fac’- and ‘mer’-coordination geometries. The luminescence quantum yields and life times of 1 and 2 were estimated to be (Φ = 0.25 and 1.40 ms) and (Φ = 0.30 and 1.23 ms), respectively.