The Dynamic Coordination Chemistry Between Organic Tellurium And Metal Ions And Its Application Research

Tellurium is located at the sixth main group of periodic table and has similar chemical properties to sulfur and selenium.Organic tellurium has an excellent electron-donating ability,coordinating with metal ions well.Furthermore,organic tellurium is highly sensitive to redox,which makes its coordination chemistry show the dynamic regulatability.It is of great significance that the contruction of novel organic tellurium dynamic coordination systems can promote the development of the tellurium chemistry and dynamically responsive functional materials.In this thesis,we synthesized of a new organic tellurium molecule,and studied the dynamic coordination chemistry between organic tellurium and metal ions and its applications in fields of smart materials and biomedicines.The main research was summarized as follows:In the first chapter,the related contents of organic tellurium chemistry,dynamic coordination chemistry,stimulus-responsive hydrogels and chemodynamic therapy were introduced,which laid the theoretical foundation for this research.In the second chapter,the tellurium-containing monomer（Acry2-Te）with acrylamide groups at both ends was synthesized,and the dynamic coordination interaction between Acry2-Te and platinum（IV）ions under oxidation and reduction was studied.Organic tellurium upon oxidative stimulus was oxidized and the coordination interaction between tellurium and platinum ions disappeared.The oxidized organic tellurium upon reducing stimulus was reduced,and the coordination interaction between tellurium and platinum ions recovered.Through the molecular thermodynamic simulation,the dynamic coordination mechanism was elucidated at the molecular level.In the third chapter,the tellurium-containing hydrogel was prepared via copolymerizing Acry2-Te and N-hydroxyethylacrylamide.Platinum ions were added to the tellurium-containing hydrogel.Organic tellurium could coordinate with platinum ions,which improved the mechanical property of the hydrogel.Adding an oxidant（such as 50 m M H₂O₂）to the hydrogel,organic tellurium was oxidized.The coordination interaction between tellurium and platinum ions disappeared,which evidently reduced the mechanical property of the hydrogel.Adding an reductant（such as 50 m M ascorbic acid）to the hydrogel after oxidation,organic tellurium was reduced.The coordination interaction between tellurium and platinum ions recovered,which improved the mechanical property of the hydrogel again.Therefore,the hydrogel was mechano-regulatable upon highly redox-active mediated by the dynamic coordination interaction between tellurium and platinum ions.In the fourth chapter,the coordination system between Acry2-Te and manganese ions(Mn²⁺)was studied.Compared with manganese ions,the coordination system（Acry2-Te-Mn）could more efficiently catalyze the decomposition of hydrogen peroxide to generate highly toxic reactive oxygen species which might cause oxidative stress in tumor cells.Acry2-Te-Mn was introduced into the DNA-crosslinked nanogel,and nucleic acid drugs were efficiently loaded via hybridization chain reaction.Thus,intelligent nucleic acid nanomedicines containing Acry2-Te-Mn were constructed.In the last chapter,the summary and prospect of this thesis were made.In this paper,the new dynamic coordination system between tellurium and platinum was developed.The dynamic hydrogel that was mechano-regulatable upon highly redox-active would provide the material support for designing of mechanically morphing smart devices.We prepared an intelligent nucleic acid nanomedicines containing Acry2-Te-Mn which would realize the synergistic therapy（gene therepy-enhanced chemodynamic therapy）and have the potential value in clinical applications.