Diels-Alder “Click” Chemistry in Designing Dendritic Macromolecules

Covalent assembly of hierarchical particles by efficient coupling of β-diketones and benzyl chloride

A coupling reaction is performed between polymeric nanoparticles and microparticles via the nucleophilic substitution of pendent β-diketone groups with benzyl chloride. The coupling reaction results in the formation of hierarchical particles, through the nanoparticles being covalently linked onto the microparticles. The coupling reaction is tracked by TEM and SEM, and the formation of covalent C-C bonds through the coupling reaction between the polymeric nanoparticles and microparticles is confirmed by solid-state (13)C CP-MAS NMR spectroscopy and XPS. The proposed coupling reaction between the nanoparticles and the microparticles is believed to be a promising strategy in particle-surface modification.

Dendrimer templated construction of silver nanoparticles

Silver nanoparticles continue to evoke great current interest due to their tremendous potential in designing smart materials for a wide variety of applications. Much emphasis has been placed lately in developing methodologies that could modulate the size and shape of these metal particles. Dendrimers that are monodisperse in nature with a regular and highly branched three-dimensional architecture, provide a useful platform to accomplish this goal. These hyperbranched macromolecules have been widely explored as templates in the construction of silver metal nanoparticles, and this review aims to provide a detailed overview of dendrimer-assisted synthesis of silver nanoparticles.

"Click" methodologies: efficient, simple and greener routes to design dendrimers

Designing dendrimers that are monodisperse hyperbranched macromolecules and offer significant potential in numerous scientific fields, is becoming a major topical area in modern research. Among the challenges of the 21st century, synthetic methodologies that increase efficiency of conversion and a greener chemistry approach, are expected to lead the way in the quest to build novel nanomaterials. The recent entry of so-called "click" reactions that include Diels-Alder, Cu(I)-catalyzed Huisgen cycloaddition and thiol-ene coupling, have generated real stimulus not only in developing elegant materials of choice, but also in making the leap to industrial scale build-up of dendritic macromolecules. This tutorial review takes on the task of demonstrating the simplicity of these "click" reactions and the advantages they offer from a synthetic view point in developing mono- to multifunctional dendrimers. A brief introduction to "click" chemistry is followed by a chronological survey of developments in the field, and the impact these have had in designing novel dendritic macromolecules. The review is intended to introduce scientists to these highly efficient methodologies with demonstrated potential, and provide impetus for further growth of the area.

Combined CuI-catalysed alkyne–azidecycloaddition and furan–maleimide Diels–Alder “click” chemistry approach to thermoresponsive dendrimers

Cu¹-catalyzed alkyne–azide and Diels–Alder “click” reactions are used in sequence, in a layer-by-layer build-up of dendrimers which undergo retro-Diels–Alder disassembly upon heating.

Dendrimers: Analytical characterization and applications

This review focuses on analytical techniques used for separation and characterization of dendrimers and their derivatives. These macromolecules have been attractive material for a development of new drug carriers and imaging agents. They are also interesting for many biological and industrial applications. The review mentions a few of them.