1,2-branched 1st to 4th generation carbosiloxane dendrimers with a Me2SiO2or MeSiO3 core

A straightforward method for the preparation of 1 --> 2-branched carbosilox ane dendrimers of the 1st to 4th generation with a Me2SiO2 or a MeSiO3 core by applying repetitive hydrosilylation-alcoholysis cycles is described. Al l dendrimers prepared contain as repeated units SiOCH2CH2CH2 entities and f eature SiMe2Cl, SiMeCl2 or Si(OCH2CH=CH2) end-grafted moieties. Depending o n the different initiator cores MeSi(OCH2CH=CH2)(3) (MeSiO3) (17) and Me2Si (OCH2CH=CH2)(2) (Me2SiO2) (1). 1,2-branched carbosiloxane dendrimers up to the 3rd (17) or 4th (1) generation are accessible. However. further hydrosi lylation of the latter molecules only results in the formation of irregular structured species, due to increasing steric congestions on the respective dendrimer surface. The formation of analytically pure and uniform carbosil oxane dendritic molecules is based on elemental analyses, IR, H-1, C-13(H-1 ) and Si-29 (H-1) NMR spectroscopic studies. From selected examples gel per meation chromatography was carried out.