Chapter 6

Selenium/tellurium containing polymer materials in nanobiotechnology

“…Zhang and coworkers demonstrated a supramolecular strategy to modulate the reactivity of Se-Se bonds [35]. Selenocystamine (SeCy) by itself was rather sensitive to redox stimuli, but upon binding with a host molecule to cucurbit [6]uril (CB [6]) (K a =5.5×10 6 M -1 ) via host-guest chemistry, however, the Se-Se became inert. Further studies revealed that SeCy-CB [6] complex was 5×10 3 time less active toward oxidation than the free SeCy.…”

“…Additionally, complete recovery of the redox properties could be achieved by disrupting the host-guest pair using a competitive guest CB [6]. This supramolecular control over the reactivity provides a possible way to modulate the selenium redox process by changing the microenvironments.…”

“…For example, in 1970s selenium was proved to be incorporated into proteins to produce selenoproteins which perform as important antioxidant enzymes [3]. Great progresses has since been made to synthesize selenium-containing compounds with anti-oxidant properties ever since [4][5][6][7]. Similarly, after the pioneering use of tellurium compounds in organic synthesis, rising interest has been directed toward the field of tellurium chemistry [8][9][10][11].…”

Dynamic Chemistry of Selenium: Se–N and Se–Se Dynamic Covalent Bonds in Polymeric Systems

“…In 1957, selenium was determined to be one of the necessary elements in the human body, after that, selenoproteins were also discovered, which prevent cell damage from free radicals. As free radicals are related to several chronic diseases, such as cancer and heart disease, various small antioxidant molecules containing selenium were synthesized and studied. − The previous applications of selenium in polymer chemistry, however, were mostly related to polyselenophenes by using their photovoltaic properties. − Selenium-containing macrocycles were also studied. , In our group, we have developed a series of selenium-containing polymers and used them in biosystems as responsive materials . In these studies, we took advantage of low bond energies of C–Se and Se–Se (C–Se, 244 kJ mol –1 ; Se–Se, 172 kJ mol –1 , while C–S, 272 kJ mol –1 ; S–S, 240 kJ mol –1 ), which makes the monoselenide and diselenide easy to be oxidized or reduced.…”