Tetrazine Dynamic Covalent Polymer Networks

Abstract

Dynamic nucleophilic aromatic substitution of tetrazines (S N Tz) has been used for the synthesis of dynamic covalent polymer networks that take advantage of both the reversible nature of the reaction and the versatility of the tetrazine ring. Polymer microspheres were easily synthesized and they were proved to be degraded either by UV irradiation or by a chemical stimulus, recovering the original monomer, which allows an efficient recycling. It was also possible to convert one polymer into another one (metamorphosis) by irreversible exchange of monomers. Additionally, the backbone of the polymers could be reduced/oxidized or postfunctionalized with polar groups by the inverse electron demand Diels−Alder (IEDDA) reaction, which not only locked the exchange but also allows for the modulation of the polymer properties, such as solubility in water. Tetrazine dynamic polymers are a recyclable and highly versatile kind of material that enables postsynthetic modulation of their properties as well as provides novel chemical methods and photodegradation. Article pubs.acs.org/Macromolecules

Sulfur in Dynamic Covalent Chemistry

“…Also, tetrazine dynamic polymer networks were synthesized which can be photodegraded or chemically degraded for recycling aims. [116]…”

Hydrogen sulphide-triggered theranostic prodrugs based on the dynamic chemistry of tetrazines

“…1a). [8][9][10] This reaction quickly exchanges phenols and thiols in positions 3 and 6 of the tetrazine ring, at Fig. 1 (a) In previous works, the dynamic nature of the aromatic substitution of tetrazines has been reported.…”

“…Indeed, it has been proved that IEDDA reaction cancels the exchange, as the resulting diazine ring is electron richer. 8,9 Therefore, the prodrug should be deactivated by such Diels Alder reaction, and no release is expected in the analogous diazine compound. In order to keep the size and geometry as similar as possible, IEDDA reaction was performed with strained alkene 6, which after elimination of nitrogen, followed by a retro-Diels Alder reaction, yields diazine Dz(CLB) 2 where the only difference with respect to Tz(CLB) 2 is a substitution of two nitrogen atoms for two C-H groups.…”

Anion-assisted amidinium exchange and metathesis

“…Development of new dynamic covalent chemistries (DCvC) benefits a wide range of research areas such as materials science, [1][2][3][4] bioconjugation, 5,6 stereoselective synthesis, 7 (bio)molecular sensing, 8,9 and the construction of mechanically interlocked architectures (MIAs). 10 Dynamic covalent reactions (DCRs) involving primary amines are especially important due to the ubiquity of this class of organic compounds.…”