Template synthesis, crystal structure and luminescent properties of neutral N4O3 tripodal LnIIIL complexes (Ln III = La3+, Eu3+, Gd3+, Tb 3+, Dy3+, Ho3+, Er3+, Tm3+ or Lu3+; H3L = Tris{[3′-(2″- pyridyl)-5′-tert-butyl-2′-hydroxybenzylidene-2-imino]ethyl}amine)

In the presence of Ln³⁺ (Ln = La, Eu, Gd, Tb, Dy, Ho, Er, Tm or Lu), tris(2-aminoethyl)amine condensed with three equivalents of 3-(2′-pyridyl)-5-tert-butyl-2-hydroxybenzaldehyde in methanol to give the neutral Schiff-base complex Ln^IIIL (Ln = La 1, Eu 2, Gd 3, Tb 4, Dy 5, Ho 6, Er 7, Tm 8 and Lu 9; H₃L = tris{[3′-(2″-pyridyl) -5′-tert-butyl-2′-hydroxybenzylidene-2-imino]ethyl}amine). The structures of compounds 4-7 were determined by X-ray crystallography. The crystal structure analyses revealed that the Schiff base behaves as a tri-deprotonated heptadentate ligand encapsulating the lanthanide metal ion within the N₄O₃ cavity, with all the pyridyl groups being pendant. Solution spectroscopic data suggest that the Ln^IIIL complexes remain intact in methanol and exist as nine-coordinate non-electrolytes with the lanthanide metal ions coordinated to the N ₄O₃ cavity of the tripodal Schiff base and two solvent molecules. The solution photoluminescent properties of these lanthanide Schiff-base complexes were also examined.