Sugar-metal ion interactions: the coordination behaviors of lanthanum with erythritol.

Three novel lanthanum chloride–erythritol complexes (LaCl3·C4H10O4·5H2O (LaE(I)), LaCl3·C4H10O4·3H2O (LaE(II)), and LaCl3·1.5C4H10O4 (LaE(III)) were synthesized and characterized by single crystal X-ray diffraction, FTIR, far-IR, THz, and Raman spectroscopy. The coordination number of La3+ is nine. LaE(I) and LaE(II) have similar coordination spheres, but their hydrogen bond networks are different. Erythritol exhibits two coordination modes: two bidentate ligands and tridentate ligands in LaE(III). Chloride ions and water coordinate with La3+ or participate in the hydrogen-bond networks in the three complexes. Crystal structures, FTIR, FIR, THz, and Raman spectra provide detailed information on the structures and coordination of hydroxyl groups to metal ions in the metal–carbohydrate complexes.