| Summary: | 碩士 === 國立中正大學 === 化學所 === 93 === We have designed and synthesized a series of 2,3-dipyrrol-2’-ylquinoxaline (DPQ) derivatives M1, M1a, M2, and quinoxaline derivative model 1 for sensing inorganic anions. Except for model 1, all others are efficient chemosensors for fluoride and pyrrophosphate. It is expected to perturb the orbital overlap between the pyrrole and quinoxaline subunits, thereby changing the optical characteristics. On the basic of the results from ESI-MS, 1H NMR titrations, Semiempirical ZINDO calculations, we have found the colorimetric respone and fluorescee quenching in these chemosensors are indeed the result of deprotonation of the N-H proton.
The equilibrium constants derived from the emission spectral titration in CH2Cl2 solution are in the order of F-＞HP2O73-＞CN-＞OAc-＞H2PO4- ＞Cl- ~ Br- ~ I- ~ NO3- and also qualitatively correlated with the basicity of these anions. In the naked-eye colorimetric experiments, the UV-Vis titration of M1、model 1 with trifluoroacetic acid in CH2Cl2 solution aslo showed dramatic color changes from yellow to red. Howere, the color change was not observed with addition of excess HOAc, DOAc, Phenol to the solution of M1 and model 1.
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