Thermosensitive Amphiphilic Janus Dendrimers with Embedded Metal Binding Sites. Synthesis and Self-Assembly

A family of amphiphilic diblock Janus dendrimers were synthesized by chemoselective "click" coupling of poly(benzyl ether) dendrons, PBE, and poly-(ether-ester), PEE, dendrons based on three different ethylene glycol spacers. The well-defined defect-free structure of these dendrimers was proven by MALDI-TOF. In aqueous solutions these dendrimers were able to self-assemble into vesicles with diameter ranging from 140 nm to 3.6 mu m or solid micelles (10 to 14 nm diameter). The form of these assemblies was affected by the spacer length between branching points and by the generations of both dendrons. The ethylene glycol moieties in the PEE dendrons induced notable thermosensitivity with sharp transitions observed for all members of the series. The presence of two triazole groups at each branching point was further exploited to fabricate palladium bearing nanomaterials with potential application in catalysis.