Theoretical study of chemosensor for fluoride and phosphate anions and optical properties of the derivatives of 2-(2-hydroxyphenyl)-1,3,4-oxadiazole

The interactions between chemosensor, 2-(2-hydroxyphenyl)-5-phenyl-1,3,4-oxadiazole (HOXD1), and different halides (F , Cl , and Br) and phosphate (H2PO4-) anions were theoretically investigated. It turned out that the unique selectivity of HOXD1 for F-/H2PO4- is ascribed to its ability of deprotonating the hydroxy group of host sensor. Optical spectra of neutral and deprotonated sensors were simulated using TD-DFT method. It was found that intermolecular proton transfer is responsible for the colorimetric and fluorescent signaling of chemosensor for F-/H2PO4-. Seven derivatives of HOXD1 have been designed. All the mono-electron-donating (-CH3, -OCH3, and -N(CH3)(2)) substituted derivatives are expected to be promising candidates for ratiometric fluorescent F-/H2PO4- chemosensors as well as chromogenic chemosensors, while para-N(CH3)(2) substituted derivative can serve as chromogenic F-/H2PO4- chemosensor only. Furthermore, the mono-electron-withdrawing (-CN and -COCH3) derivatives are promising electron transport and luminescent materials for OLEDs as well. (C) 2010 Elsevier B.V. All rights reserved.