Smart Transformation of a Polyhedral Oligomeric Silsesquioxane Shell Controlled by Thiolate Silver(I) Nanocluster Core in Cluster@Clusters Dendrimers

Using polyhedral oligomeric silsesquioxane (POSS) modified by a thiol group as a protected ligand, atom-precise multi-heteorocluster-based dendrimers Ag-12@POSS6 (1a and 1b) were assembled. Through the reactive -SH groups, six POSS shell ligands stabilize the central 12-core silver(I) cluster by diverse Ag-S interactions. When such Ag-12@POSS6 complex was stimulated by different solvents (acetone or tetrahydrofuran), the core Ag-12 silver(I) cluster underwent reversible structural transformation between flattened cubo-octahedral (in 1a) and normal cubo-octahedral (in 1b); concomitantly shell POSS clusters rearranged from pseudo-octahedral to quasi-octahedral. Furthermore, the film matrix modified by 1a or 1b showed different hydrophobicity.