Design, Synthesis And Study Of Chiral Sulfur Oligomers

The present research on sulfur-containing chiral oligomer in the main chain has not received great attention, which could expand the types of functional chiral oligomer. The sulfur atom is a kind of "soft" atom, and it can form strong bond with the soft metal (such as palladium, etc.), which has a strong coordination bonding ability to transition metal ions. Therefore, introduction of sulfur atoms into the main chain of poly chiral dithuranes could bring new properties to polymers which may show the application in the field of supramolecular chemistry. In this paper, poly chiral sulfur ethers were synthesized from optically active chiral sulfur ether monomers, and the applications of the polymers in ionic and enantioselective recognition were also carefully studied. The research works were listed as following:2-Naphthol, coumarin and triphenylmethane was used as starting material respectively, which reacted with S-epoxy chloropropane to give optically active epoxy compounds, then with SCN- as a reagent to afford chiral thuranes monomer. The chiral oligomers b2,c3,d3 were obtained by anionic polymerization in bulk or solution. We also used dichloro-diethyl ether and 1,3-diphenol to afford 2,2’-((oxybis(ethane-2,1-diyl)) bis(oxy)) diphenol crown ether, then reaction with S-epoxy chloropropane, and SCN- as a reagent to produce chiral dithiiranes monomer, which was polymerized to get poly chiral dithuranes a3. The structure of all intermediates, target products and the chiral polymers was characterized by nuclear magnetic resonance (NMR).In order to further study its functional properties, for example, for ion recognition, chiral recognition, a series of tests, such as ultraviolet and fluorescence spectra, were performed. We found that the oligomer a3 exhibit good recognition for copper and mercury ions, and also show good recognition for the (R)-naphthol and (S)-naphthol; oligomer b2 exhibit recognition for mercury and chromium ions, but it seems to show no recognition on enantiomers; polymer c3 was not studied due to its poor solubility.In addition, in order to improve the main chain rigidity of the polymer containing sulfur atoms and form stable helical structure in solution, the experiment of oxidation poly sulfur ether d3 into sulfoxide d4 was performed. Oligomer d3 showed the similar optical rotation to that of d4, which hinted that the main structure does not become more rigid when the main chain of C-S-C bond changes to a C-S(O)-C.