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.