Sugar interaction with metal ions. The crystal structure and Raman spectra study of SmCl3–galactitol complex

Abstract

The crystal structure of 2SmCl3·galactitol·14H2O has been determined. The crystal system is triclinic, space group: P-1. The unit cell dimensions: a=9.683(2) Å, b=10.341(2) Å, c=7.990(2) Å; α=108.01(3)°, β=92.71(3)°, γ=88.42(3)°. Each Sm atom is coordinated to nine oxygen atoms, three from the alditol and six from water molecules, with Sm–O distance from 2.417 to 2.520 Å. The seventh water molecule is hydrogen-bonded by the hydroxy hydrogen on O–3 (O(3)–H(13)⋯O(10), 2.635 Å). After forming complexes the peaks have shifted and the relative intensities have changed in the IR and Raman spectra, which are corresponding to the changes in bond distances and bond angles of the structures. The IR and Raman spectra of Pr–, Nd– and Sm–galactitol complexes are similar, which show that the three metal ions have the same coordination mode.