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

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 Na<SUB>3</SUB>[Mo<SUB>154</SUB>O<SUB>462</SUB>H<SUB>14</SUB>(H<SUB>2</SUB> O)<SUB>48</SUB>(HO<SUB>2</SUB>C-(NH<SUB>3</SUB><SUP>+</SUP>)HC -CH<SUB>2</SUB>-S-S-CH<SUB>2</SUB>-CH(NH <SUB>3</SUB><SUP>+</SUP>)-COO<SUP>-</SUP>)11] ·x H<SUB>2</SUB>O 1 (x ≈250) containing nanosized ring-shaped clusters which capture the oxidation product of cysteine, i.e. the diprotonated cystine ligands (H<SUB>2</SUB>cystine<SUP>+</SUP>) at the inner wall of their cavities; interestingly, the multiphilic ligands containing different types of functional groups (two -NH<SUB>3</SUB><SUP>+</SUP>, one -CO<SUB>2</SUB><SUP>-</SUP>, one -CO<SUB>2</SUB>H 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