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 termina ted carbosilane dendrimers and ally1-1,1-dihydrofluoroethyl ether or ally1- 1,1-dihydroheptadecafluorononyl ether through divergent synthetic routes: S i[CH2CH2SiMe2(CH2CH2CH2OCH2CF3)](4) (7),Si{CH2CH2SiMe[CH2CH2SiMe(CH2CH2CH2O CH2CF3)(2)](2)}(4) (8), Si[CH2CH2Si(CH2CH2CH2OCH2C8F17)(3)]4 (9), Si[CH2CH2 SiMe2(CH2CH2CH2OCH2C8F17)](4) (10), and Si{CH2CH2Si[CH2CH2Si(CH2CH2CH2OCH2C 8F17)(3)](3)}(4) (11) These compounds were characterized by elemental and s pectroscopic analyses. Valuable mass spectral data were obtained by using a tmospheric pressure chemical ionization (APcI). The fluorinated dendrimer m olecule and the nonfluorinated core scatter X-ray light differently and pre sent 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.