Synthesis and computer modelling of hydroxy-derivatised carbosilane dendrimers based on polyhedral silsesquioxane cores

Abstract

Divergent synthesis methods have been used to prepare 2nd generation dendrimers based on polyhedral silsesquioxane cores with up to 72 terminal groups at their surface. Repetitive hydrosilation/allylation of vinyl-functionalised polyhedral silsesquioxanes produce chlorosilyl- and allyl-derivatised dendrimers respectively. Hydroboration/oxidation of the allyl-functionalised dendrimers produces alcohol (hydroxy) terminated dendrimers. Energy minimisation and molecular dynamics techniques have been used to model the architectures of the dendrimers. The results show the dendrimers are relatively spherical, globular molecules, with a large proportion of the terminal hydroxy groups located in a shell at the exterior of the dendrimer. As the number of terminal groups on the dendrimers increases the number of the dendrimer branches that back fold towards the core of the dendrimer also increases.