Study On The UV And Fluorescent Chiral Sensors Of Optical Active Diethyl Tartrates And Polytartaramides

In the paper, two optical active polytartaramides (PITAs) were synthesized through bulk polycondensation from isophoronediamine (IPDA) and chiral diethyl tartrates (DETs). The structures of PITAs were characterized from the reaction of 2-formylphenyl boronic acid and chiral S-?-phenylethylamine with PITAs. Tartaramide-and polytartaramide-linked SiO2 (SiO2-TA or SiO2-PTA) substrates were also prepared. Chiral recognition of DETs, PITAs and SiO2-TAs or SiO2-PTAs was studied with 1,1'-bi-2-naphthols (BINOL) as a fluorescent sensor. Finally, a new thiourea color sensor (TUD) was synthesized from the reaction of S-phenylethylamine and 4-nitrobenzene thioisocyanate. The UV and color recognition of DETs was studied with TUD as a chiral sensor. Meanwhile, the fluorescent chiral recognition of PITAs was studied with TUD. The main contributions are described as follows:(1) Two optical active PITAs were synthesized through bulk polycondensation from IPDA with D-DET and L-DET, respectively. They are soluble in polar solvents, such as H2O, ethanol and so on, but are insoluble in non-polar solvents, such as THF, chloroform and the like. PITAs exhibit Mn above 100,000 and Mw above 300,000. PITAs show optical activity of about 60°, while the DETs exhibit optical activity of 8.9°. The configuration of tartarate units was maintained during the polycondensation from chiral DETs to PITAs. The configurations of PITAs were also characterized through the reaction of 2-formylphenyl boronic acid and S-a-phenylethylamine with PITAs and 1H NMR sprectra.(2)The chiral recognition of L-DET and D-DET with BINOL was studied in ethanol, chloroform and toluene solution. The results show that enantiomer DETs were not recognized by BINOL in a polar ethanol solution. L-DET enhances stronger the BINOL fluorescence intensity than D-DET in non-polar solvent like chloroform or toluene. DETs can be chirally recognized with BINOL as a fluorescent sensor. Meanwhile, BINOL was used as a chiral fluorescence sensor for L-PITA and D-PITA in chloroform. The quenching effect of L-PITA on BINOL fluorescence is stronger than D-PITA. As the PITA concentration increased, the chiral recognition sensitivity increases substantially. L-DET, D-DET, L-PITA and D-PITA were also coupled respectively onto (3-aminopropyl) trimethoxysilane modified SiO2, and and SiO2-TA or SiO2-PTA substrates were prepared. Their chiral recognition was also studied with BINOL. BINOL is an effective chiral fluorescence sensor for DETs, PITAs, and SiO2-TA or SiO2-PTA substrates(3) A new thiourea color sensor TUD was synthesized from the reaction of S-phenylethylamine and 4-nitrobenzene thioisocyanate at room temperature 24h, and was characterized by FT-IR and 1H NMR. Its melting point was 114.5-115.5?. Chiral recognition of DETs was studied with TUD as UV and color sensor in DMSO. At the wavelength of 358nm, as the D-DET concentration increased, the UV absorbance of TUD decreased obviously, while no increase of the UV absorbance was observed at the same L-DET concentration. At the wavelength 483nm, with the increase of D-DET concentration, the UV absorption of TUD became stronger, while no this phenomenon occurred as the L-DET concentration increased. Meanwhile, with the increase of D-DET concentration, TUD solution turned gradually from colorless to pale yellow, but no color change occurred at the same addition of L-DET. Thus, TUD is a UV and color chiral sensor for L-DET and D-DET recongnition. L-PITA enhanced TUD fluorescence greater than D-PITA. TUD also chirally recognize PITAs with different configurations via fluorescence in DMSO.