CARBOSILANE-BASED DENDRITIC POLYOLS

A divergent hydrosilation/Grignard-reaction sequence, followed by hydr oboration of the allyl end groups was employed to prepare a series of novel dendritic carbosilane polyols. Dendrimers with 4, 12, 36, and 10 8 hydroxyl end groups have been prepared. The hydroboration reactions were monitored by H-1-NMR and MALDI-TOF and were quantitative in all c ases. Using MALDI-TOF, the carbosilane dendrimers as well as the novel dendritic polyols have been characterized directly with respect to po lydispersity. Whereas G2-OH consisted of mainly two species, the desir ed 36-ol (80%) and the 34-ol, G3-OH consisted of polyols with 92-108 h ydroxyl groups. The dendritic polyols possess low glass transition tem peratures (233-241 K) and thus constitute flexible polyols without pol ar interactions between the dendrons. The molecules appear suitable as chemically stable, flexible molecular scaffolds for the construction of unusual supermolecular architectures.