Málmhvötuð brennisteinsálagning á alken - verkefni lokið
Fréttatilkynning verkefnisstjóra
Thiiran eru lífræn efnasambönd hliðstæð epoxy efnum nema thiiran innihalda brennistein í stað súrefnisatóms. Thiiran eru upphafsefni notuð í brennisteinsríkar fjölliður, gjarnan með kolefnisdísúlfíði. Slíkar fjölliður hafa lágan brotstuðul ljóss og eru eftirsótt efni í dýr ljósmælitæki og sólarrafhlöður.
Fjölliðurnar hafa einnig hagnýtingu sem hágæðagler í gleraugu með lágmarkaðri bjögun, litrófsháða skynjara, og mæla. Hins vegar eru efnasmíðar thiirana flóknar þar sem almennt hvarf til að búa til fjölbreytt thiiran skortir. Fræðilega er hægt að smíða þau með álagningu brennisteins á alken, en oftast eru þau búin til með því að smíða fyrst tilsvarandi epoxíð og framkvæma svo atómskiptihvarf, sem ganga misjafnlega. Oftast er hvert thiirane smíðað eftir sérhannaðri aðferð sem er bæði dýrt og takmarkar hugsanlega fjölbreytni fjölliða sem hægt er að smíða. Í þessu verkefni var unnið að málmhvataðri brennisteinsálagningu á alken. Sérhannaður málmhvati var smíðaður og hæfileikar hans til að aðstoða við álagningarhvarfið rannsakaðir. Brennisteinsatóm flutningur frá thiiran til málmsins, svo og flutningur brennisteins frá brennisteinsríkum málm til alkens var rannsakaður. Niðurstöðurnar voru mjög jákvæðar og staðfestu að flutningur brennisteins tókst í báðar áttir. Þessar niðurstöður gefa góða ástæðu til að halda áfram með verkefnið og rannsaka næst myndun fjölbreyttari thiiran efna, hvarfgang hvarfsins, og fjölliðun við CS2.
English:
Thiiranes are organic compounds parallel to epoxides except thiiranes contain a sulfur atom in place of an oxygen atom. Thiirane are important starting materials for sulfur-rich polymers often with carbon disulfide. Such polymers have very low refraction index and are expensive and sought-after materials for advanced optical applications and solar panels. Such thermoset polymers display outstanding optical qualities and high refractive index.
Limited number of substituted thiiranes is synthetically accessible in meaningful yields due to synthetic challenges in sulfur addition reactions to alkenes and a lack of a general reaction for this transformation. The thiiranes formed are normally obtained through an optimization for each substrate, and often by first synthesizing the corresponding epoxide. A single-step metal mediated reaction to form novel thiiranes was studied. The approach employed complexes with tunable ligands that easily accommodate sulfur atom during the atom transfer reaction. The "S" atom transfer reactions from thiirane to metal, and episulfidation reaction of a sulfur-rich metal to alkene were studied. The project research goal is to determine feasibility of this system as a general synthetic route for thiiranes. The results showed the system under study was capable of transferring sulfur to and from the complex to an alken. The results were encouraging and support further studies to evaluate the reaction mechanism, expand to more substrate variety and attempt copolymerization with CS2.
• Information on how the results will be applied
Research Question output:
Initial question related to if it is possible to achieve a general reaction for the sulfuration of unsaturated bonds in organic molecules. This question was not fully answered. However, the results obtained suggest that using metal complexes for such sulfuration reaction is indeed worthy of attention and further study. Furthermore, highly valuable copolymers for optical applications appear achievable. An application for a second project for further studies on the copolymers was submitted.
• A list of the project’s outputs
3 PhD students participated
3 MS students participated
2 BS student projects
2 RA employees participated at BS and MS level for short term project.
Four theses were produced. Two graduate and two undergraduate level. A PhD that will be the first PhD thesis from this work exclusively is expected in 2023. One MS thesis was exclusively from this project while the remaining students did collaborations along with other projects as their main efforts. From that group two PhD students graduated.
Three scientific papers, and four conference proceedings have been published. Three more scientific papers are in preparation.
Heiti verkefnis: Málmhvötuð
brennisteinsálagning á alken / Metal Catalyzed Episulfidation of Alkenes
Verkefnisstjóri: Sigríður Guðrún Suman,
Raunvísindastofnun
Tegund styrks: Verkefnisstyrkur
Styrktímabil: 2017-2019
Fjárhæð styrks: 47,942 millj. kr. alls
Tilvísunarnúmer Rannís: 173667
