CARBOSILANE-BASED DENDRITIC POLYOLS

A divergent hydrosilation/Grignard-reaction sequence, followed by hydroboration of the allyl end groups was employed to prepare a series of novel dendritic carbosilane polyols. Dendrimers with 4, 12, 36, and 108 hydroxyl end groups have been prepared. The hydroboration reactions were monitored by H-1-NMR and MALDI-TOF and were quantitative in all cases. Using MALDI-TOF, the carbosilane dendrimers as well as the novel dendritic polyols have been characterized directly with respect to polydispersity. Whereas G2-OH consisted of mainly two species, the desired 36-ol (80%) and the 34-ol, G3-OH consisted of polyols with 92-108 hydroxyl groups. The dendritic polyols possess low glass transition temperatures (233-241 K) and thus constitute flexible polyols without polar interactions between the dendrons. The molecules appear suitable as chemically stable, flexible molecular scaffolds for the construction of unusual supermolecular architectures.