Preparation and characterization of nonpolar fluorinated carbosilane dendrimers by APcI mass spectrometry and small-angle X-ray scattering

The following highly fluorinated nonpolar dendrimers were obtained in high yields from multiple hydrosilylation reactions between core hydride terminated carbosilane dendrimers and ally1-1,1-dihydrofluoroethyl ether or ally1-1,1-dihydroheptadecafluorononyl ether through divergent synthetic routes: Si[CH2CH2SiMe2(CH2CH2CH2OCH2CF3)](4) (7),Si{CH2CH2SiMe[CH2CH2SiMe(CH2CH2CH2OCH2CF3)(2)](2)}(4) (8), Si[CH2CH2Si(CH2CH2CH2OCH2C8F17)(3)]4 (9), Si[CH2CH2SiMe2(CH2CH2CH2OCH2C8F17)](4) (10), and Si{CH2CH2Si[CH2CH2Si(CH2CH2CH2OCH2C8F17)(3)](3)}(4) (11) These compounds were characterized by elemental and spectroscopic analyses. Valuable mass spectral data were obtained by using atmospheric pressure chemical ionization (APcI). The fluorinated dendrimer molecule and the nonfluorinated core scatter X-ray light differently and present unique slopes on the Guinier Plot of data from small-angle X-ray light scattering (SAXS) in hexafluorobenzene. Glass transition temperatures (T-g) and thermogravimetric analyses (TGA) of the dendrimers were determined.