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

–

HSO

4

–

Br

–

and NO

3

–

indicating the F

–

sensing ability of poly(

1

) and poly(

2

). The

1

H-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.