Carbosilane Dendrimers with Perfluoroalkyl End Groups. Core−Shell Macromolecules with Generation-Dependent Order

Abstract

A series of carbosilane dendrimer generations, G0 to G3, with 4, 12, 36, and 108 end groups, respectively, has been functionalized with perfluorohexyl (C6F13−) groups on the surface. Quantitative perfluoroalkylation of the dendrimer surface was achieved via free radical addition of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-n-octyl mercaptan. Quantitative perfluoroalkylation of the dendrimers was demonstrated by NMR and SEC. The thermal properties of the dendrimers with core−shell structure were investigated by DSC, polarizing microscopy, and WAXS. Whereas G0 was obtained as a crystalline material that did not show the formation of mesophases, G1 (12 end groups) exhibited the formation of a highly ordered smectic mesophase between −15 and −30 °C. In contrast, G2 and G3 did not form mesophases; however, a transition to a most probably hexagonally ordered array of columns could be observed. The generation-dependent thermal behavior is ascribed to the increasingly dense packing of perfluorohexyl groups on the dendrimer surface.

Self-assembly using dendritic building blocks—towards controllable nanomaterials

“…Furthermore, peripheral groups are able to modify the assembly mode of dendrons -for example transforming a spherical assembly built up from multiple dendron cones into a stacked pyramidal columnar array [162]. Similar effects of fluorous groups on assembly processes have also been reported by other workers [163].…”

Size‐Tunable Micron‐Bubbles Based on Fluorous–Fluorous Interactions of Perfluorinated Dendritic Polyglycerols

“…This is also reported for other dendrimers with perfluorinated shell. [20] The small solubilities of the higher generations are still sufficient for recording a were realized, whereby the number of peaks increased with the generation to 8, 9, and 12 peaks, respectively. In the interval region of À80 at À84 ppm, there are two peaks that can be attributed to CF 3 groups (Figure 2).…”

Siloxane and Carbosiloxane Based Dendrimers: Synthesis, Reaction Chemistry, and Potential Applications

“…[75,76] Thus, the reaction of, e.g., Si(O(CH 2 ) 3 SiMeCl 2 ) 4 (108) with BrMg-CH 2 CH=CH 2 produces Si(O(CH 2 ) 3 SiMe(CH 2 CH=CH 2 ) 2 ) 4 (109). Hydrosilylation of the latter molecule with the dichlorosilane H±SiMeCl 2 in presence of catalytic amounts of platinic acid affords the terminal SiMeCl 2 -functionalized dendritic molecule Si(O(CH 2 ) 3 SiMe((CH 2 ) 3 SiMeCl 2 ) 2 ) 4 (110), which on further treatment with HOCH 2 CH=CH 2 in presence of NEt 3 yields the second generation dendrimer Si(O(CH 2 ) 3 -SiMe((CH 2 ) 3 SiMe(OCH 2 CH=CH 2 ) 2 ) 2 ) 4 (111). [75] The above described dendrimers were characterized by, e.g., elemental analysis, MALDI-TOF-MS or ESI-TOF-MS (ESI = electro-spray ionization), GPC as well as IR and NMR techniques.…”