Two copper(II) complexes [CuL(1)Cl]ClO(4) and [CuL(2)MeCN](ClO(4))(2)xH(2)O were synthesized (L(1)= 1-(benzimidazole-2-ylmethyl)-1,4,7-triazacyclononane, L(2)= 1,4-bis(benzimidazole-2-ylmethyl)-1,4,7-triazacyclonone). The benzimidazole groups were N-substituents of tacn, and the complexes are more stable than their parents. They are able to catalyse the dismutation of superoxide anion in aqueous solutions at physiological pH and in bovine serum albumin solution (0.5 mg ml(-1)). X-ray structure analysis and EPR and electronic spectra show that the structure of complex is more similar to the Cu(II) centre of Cu(2)Zn(2)SOD than that. Comparing with other Cu(II) complexes, the complex possesses both high SOD activity and highly thermodynamic stability.

,7-triazacyclonone) and characterized by standard physical methods. The new complexes have better stability than the parent complex due to the introduction of benzimidazole groups on the backbone of tacn. The

Four heterodinuclear cryptates [EuML(dmf)](ClO4)2 (M=Ca, Cd, Ni, Zn) were synthesized by a two‐step method (L denotes deprotonated anionic cryptand synthesized by condensation of tris(2‐aminoethyl)amine with 2,6‐diformyl‐4‐chlorophenol). The ES‐MS spectra of the four cryptates and the crystal structure of [EuNiL(dmf)](ClO4)2⋅MeCN confirm that a strict dinuclear EuIII–MII entity exits in the cryptates. The cyclic voltammetry and luminescence spectral investigations indicate that the introduction of second metal ions into the mononuclear EuIII cryptate result in a negative shift of the redox potential of EuIII and a change in luminescence intensity of EuIII. The cryptate [EuML(dmf)](ClO4)2 was shown to quench the emission of EuIII when M=Ni and to enhance the emission of EuIII when M=Ca, Cd, and Zn in the sequence: mononuclear

Two new ligands consisting of a fluorenyl and dioxotetraaza unit, namely, 2,10-diamino-6-(9H-fluoren-9-yl)-4,8-diazaundecane-5,7-dione (L 1 ) and 1-(9H-fluoren-9-yl)-1,4,7,10-tetraazadecane-5,6-dione (L 2 ) along with their copper(II) complexes have been synthesized. Their properties were examined by ES-MS and CV in aqueous solution and the crystal structure of the copper(II) complex of L 1 has also been deter- [a] mined. The recognition of the transition metal ions (Cu 2+ , Ni 2+ , etc.) by receptors has been studied in aqueous solutions using pH-potentiometric and fluorimetric titrations. The results show that the binding of Cu 2+ or Ni 2+ ion with L 1 leads to quenching of the fluorescence of the fluorenyl group, but on the contrary the fluorescence of L 2 is enhanced. The mechanisms are discussed.Scheme 1. Syntheses of ligands and complexes

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