Template syntheses and properties of copper(II)-lanthanide(III) complexes of phenol-based symmetric and unsymmetric dinucleating macrocycles

Cu(II)-Ln(III) complexes of H₂(fsal-n,m) ((n,m = (2,3), (3,2) (3,3); Ln = Lanthanide), fsal-n,m-Cu,Ln, have been synthesized by a template reaction, where fsal-n,m^2- denotes dinucleating macrocycles with two 2,6-6bis(iminomethyl)-4-methylphenolate entities combined through two lateral chains, -(CH₂)_n- and -(CH₂)_m-, at the imino nitrogens. Temperature dependences of magnetic susceptibilities for the Cu(II)-Gd(III) complexes showed that an intramolecular ferromagnetic interaction operates between Cu(II) and Gd(III) ions in fsal-2,3-Cu,Gd and fsal-3,2-Cu,Gd. Absorption spectra suggested that substrates possessing N- and O-donor groups such as amino alcohols are specifically bound at the Cu-Ln centre of fsal-2,3-Cu,Ln, through the nitrogen to the copper site and through the oxygen to the lanthanide site. The fluorescence intensity of Eu(III) decreased drastically on forming the Cu-Eu complex.