Colourless crystals of complex 2 were obtained in a similar method by using the ligand bik-Me instead of ligand bik-Et (Figure ). For complex 3, the reaction of three equivalents of acetylacetone and triethylamine with one equivalent of Dy(NO3)35H2O in methanol produced a colourless solution. The successive addition of a methanolic solution of bik-Et ligand into the above reaction mixture produced a very pale-yellow solution. After filtration, slow evaporation of the filtrate yielded analytically pure crystals of 3 (Figure ).