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Novel acetylenes carrying urea groups, 1-(4-ethynylphenyl)-3-(4-nitrophenyl) urea (1), 1-(4-propargyl)-3-(4-nitrophenyl) urea (2), were synthesized and polymerized with rhodium catalyst. Polymers [poly(1) and poly(2)] with moderate molecular weights were obtained in good yields. The anion sensing ability of poly(1) and poly(2) was estimated using the tetra-n-butylammonium (TBA) salts of a series of anions in DMF. Upon the addition of F-, the color of the DMF solution of poly(1) and poly(2) immediately turned to a different color, while the color of solution changed slightly upon addition of Cl-, HSO4-, Br-, and NO3-, indicating the F- sensing ability of poly(1) and poly(2). The 1H-NMR titrations of poly(1) revealed that the colorimetric response of poly(1) was triggered by the urea/F- interaction through the hydrogen bonding and/or deprotonation process. The absorption spectra titration and Hill plot analysis were carried out to measure the F- binding ability, and the Hill coefficient in the poly(1)/F- complexation was found to be 5.8. This result clearly indicated that this binding mode between poly(1) and F- was based on a positive homotropic allosterism.
Novel acetylenes carrying urea groups, 1- (4-ethynylphenyl) -3- (4-nitrophenyl) urea (1), 1- (4-propargyl) -3- Polymers [poly (1) and poly (2)] with moderate molecular weights were obtained in good yields. The anion sensing ability of poly (1) and poly (2) was estimated using the tetra-n-butylammonium TBA) salts of a series of anions in DMF. Upon the addition of F-, the color of the DMF solution of poly (1) and poly (2) immediately turned to a different color, while the color of solution changed slightly later addition The Cl-, HSO4-, Br-, and NO3-, indicating the F-sensing ability of poly (1) and poly (2). The1H-NMR titrations of poly (1) revealed that the colorimetric response of poly ) was triggered by the urea / F-interaction through the hydrogen bonding and / or deprotonation process. The absorption spectra titration and Hill plot analysis were carried out to measure the F-binding ability, and the Hill coefficient in the poly (1) / F-complexation was found to be 5.8. This result clearly indicates that this binding mode between poly (1) and F-was based on a positive homotropic allosterism.