Synthesis of imidazolium salt-terminated poly(amidoamine)-typed POSS-core dendrimers and their solution and bulk properties

Abstract

Imidazolium bromide-terminated first and second generation poly(amidoamine) (PAMAM)-typed polyhedral oligomeric silsesquioxane (POSS)-core dendrimers, denoted as POSS-PIm16Br and POSS-PIm32Br, respectively, were prepared by the reaction of the corresponding imidazole-terminated PAMAM-typed POSS-core dendrimers with 1-bromopropane. The structures of POSS-PIm16Br and POSS-PIm32Br were identified using multinuclear nuclear magnetic resonance data, MALDI-TOF-MS spectra, and elemental analysis. Wide-angle X-ray scattering (WAXS) data for cast films of the imidazolium hexafluorophosphate (PF6)-terminated first and second generation POSS-core dendrimers, denoted as POSS-PIm16PF6 and POSS-PIm32PF6, respectively, which were prepared by anion exchange reactions of POSS-PIm16Br and POSS-PIm32Br, were characterized by the occurrence of two amorphous halos, with a strong peak at q=15 nm−1 and another weak peak around q=10 nm−1. Our present X-ray diffraction data for the cast films of POSS-PIm16PF6 and POSS-PIm32PF6 reflect the same features that were described for 1-butyl-3-methylimidazolium hexafluorophosphate. Ionic conductivities for the imidazolium bis(trifluoromethanesulfonyl)imide (TFSI)-terminated POSS-core dendrimers, which were prepared by anion exchange reactions of POSS-PIm16Br and POSS-PIm32Br, were estimated by the ac impedance method after the addition of LiTFSI. Maximum ionic conductivity of 4.03 × 10−5 S cm−1 at 51 °C was observed for the POSS-core dendrimer of lower generation and less lithium salt addition. Imidazolium salt-terminated first and second generation poly(amidoamine)-typed polyhedral oligomeric silsesquioxane (POSS)-core dendrimers were prepared. Wide-angle X-ray scattering (WAXS) data for cast films of the imidazolium hexafluorophosphate (PF6)-terminated first and second generation POSS-core dendrimers reflect the same features that were described for 1-butyl-3-methylimidazolium hexafluorophosphate. Ionic conductivities for the imidazolium bis(trifluoromethanesulfonyl)imide (TFSI)-terminated POSS-core dendrimers were estimated by the ac impedance method after the addition of LiTFSI. Maximum ionic conductivity of 4.03 × 10−5 S cm−1 at 51 °C was observed for the POSS-core dendrimer of lower generation and less lithium salt addition.