New amino acid ligated yttrium hydroxy clusters

The synthesis of the four mixed pentanuclear yttrium hydroxy clusters [Y5(OH)5(α-AA)4(Ph2acac)6] (α-AA = D-phenyl glycine, L-proline, L-valine, and L-tryptophan; Ph2acac = dibenzoylmethanide) is reported. The solid state structures of all compounds were established by single crystal X-ray diffraction. In these enantiomerically pure chiral clusters the dibenzoylmethanide and amino acid ligands are accommodated in the coordination spheres of the yttrium atoms. The specific optical rotations of all four compounds were determined. PGSE NMR diffusion measurements as function of concentration have been carried out on one model cluster, proving these molecules to be prone to aggregation in chloroform solutions.