Dendrimer Synthesis

Dendrimers are nano-sized, radially symmetric molecules with well-defined, homogeneous, and monodisperse structure consisting of tree-like arms or branches. They are characterized have special features, including mono-dispersity, multivalency and globular shape, which make them promising candidates for many applications such as anticancer therapies and diagnostic imaging light/energy harvesting and catalysis^[1]. However, very few products utilizing dendrimers and one of main reasons is the challenge related to their synthesis. In 2001, the field of dendrimers was greatly advanced with the emergence of "click chemistry". Especially the modified Hüisgen cycloaddition, which makes it easier for researchers to design and construct dendrimers. Scheme 1 shows the anatomical structure of the AB2-type dendrimer.

Scheme 1. Anatomical structure of the AB2-type dendrimer. (Each branch is made of a monomer A that splits into two B monomers. "G" stands for generation).

Applications

• Dendrimer synthesis by thiol-ene click reaction

Thiol-ene click reactions are compatible with water and oxygen and can be performed without solvent or photochemical initiation. Zhang et al^[2]. developed an efficient and facile method for constructing carbosiloxane dendrimers by thiol-ene reaction. This method can achieve the synthesis of fifth generation dendrimers in a single day starting from readily available materials. The sequential process was conducted under benign reaction conditions without the use of metal catalysts, fitting the criterion of green chemistry. Therefore, thiol-ene click reaction offers an alternative approach to dendrimer synthesis.

• Dendrimer synthesis by CuAAC click reaction

Copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is an efficient and simple approach to dendrimer synthesis with high purity and excellent yield. In a study, the individual branch or dendron was built sequentially by CuAAC click reaction, starting on the "outside" of the molecule. Then, they were coupled to a multivalent center piece ("core") in the last step, which led to the formation of a variety of dendrimers with different chain-end groups and internal repeat units^[3]. The process is simple-it works well in an aqueous solution without protection from oxygen and produces few by-products.

What Can We Do?

Alfa Chemistry has a strong research foundation in the field of dendrimer synthesis by click chemistry. We have ability to help you explore the various applications of click chemistry and provide you with related click chemistry reagents, technical advice and services. If you have problems, please don't hesitate to contact us.

References

1. Arseneault, M.; et al. Recent advances in click chemistry applied to dendrimer synthesis. Molecules. 2015, 20: 9263-9294.
2. Zhang, Z.; et al. Facile and efficient synthesis of carbosiloxane dendrimers via orthogonal click chemistry between thiol and ene. Macromolecular Rapid Communications. 2016, 37: 318-322.
3. Wu, P.; et al. Efficiency and fidelity in a click-chemistry route to triazole dendrimers by the copper(I)-catalyzed ligation of azides and alkynes. Angewandte Chemie. 2004, 43: 3928-3932.