Double-stage convergent approach for the synthesis of functionalized dendritic aliphatic polyesters based on 2,2-bis(hydroxymethyl)propionic acid

Henrik Ihre, Anders Hult*, Jean M.J. Fréchet, Ivan Gitsov

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

285 Scopus citations

Abstract

The fourth generation tridendron dendrimer based on 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) with 48 hydroxyl groups was synthesized in high yields using N,N′-dicyclohexylcarbodiimide (DCC) for the coupling steps. A double-stage convergent approach reduced the number of synthetic and liquid chromatographic steps required in the synthesis and purification of the final dendrimers. The hydroxyl functional dendrimer was subjected to a variety of surface modifications by reaction with different acid chlorides. The acetonide, hydroxy, acetate, n-octanoate, n-palmitoate, and benzoate end-functionalized dendrimers showed large differences in thermal and solution behavior depending on the nature of their end groups. The glass transition temperature varied from -4 °C for the acetate-terminated dendrimer to +57 °C for the hydroxyl-functionalized dendrimer. Dendrimers terminated with long alkyl chains were highly soluble in hexane and dichloromethane and poorly soluble in water and methanol whereas the hydroxy-terminated dendrimer showed the opposite solution behavior. All surface modified dendrimers were amorphous according to differential scanning calorimetry (DSC) except for the n-palmitoate-terminated dendrimer that showed a distinct melting transition at +28 °C in its DSC trace due to the crystallization of the long alkyl chains.

Original languageEnglish (US)
Pages (from-to)4061-4068
Number of pages8
JournalMacromolecules
Volume31
Issue number13
StatePublished - Jun 30 1998
Externally publishedYes

ASJC Scopus subject areas

  • Materials Chemistry

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