Water-soluble chiral coordination polymers of Li, Na, K, and Ba with an anionic iron(III) complex of a L-threonine derivative and a significant red shift of visible spectra with Al salt.

Four salts of an anionic iron(III) bis-complex, [Fe(L)], were synthesized from water or methanol. HL is a tridentate ligand derived from the L-threonine amino acid, and the cations used are Li (1), Na (2), K (3), and Ba (4). Single-crystal X-ray diffraction showed that all the complexes are coordination polymers of different dimensionalities.