On the option of generating novel type surfaces with multiphilic ligands within the cavity of a giant metal-oxide based wheel type cluster: chemical reactions with well-defined nanoobjects

Abstract

The reaction of an aqueous solution of sodium molybdate with cysteine hydrochloride acting as educt and reducing agent at rather low pH values (≈1.5) results in the formation of Na₃[Mo₁₅₄O₄₆₂H₁₄(H₂ O)₄₈(HO₂C-(NH₃⁺)HC -CH₂-S-S-CH₂-CH(NH ₃⁺)-COO^-)11] ·x H₂O 1 (x ≈250) containing nanosized ring-shaped clusters which capture the oxidation product of cysteine, i.e. the diprotonated cystine ligands (H₂cystine⁺) at the inner wall of their cavities; interestingly, the multiphilic ligands containing different types of functional groups (two -NH₃⁺, one -CO₂^-, one -CO₂H and one -S-S-) attach to the inner wall of the cluster through one of the two carboxylate groups thereby demonstrating the possibility to generate novel type surfaces within the cavity of a nanostructured ring-shaped cluster.