An Imidazole-functionalized Polyacetylene: Convenient Synthesis and Selective Chemosensor for Metal Ions and Cyanide Na 2 Hpo 4 ·12h 2 O, Naclo 4 , Kcns and Naf Were of Analytical Grade, and Purchased from Sinopharm

Materials and Instrumentations N, N-Dimethylformamide (DMF) was dried over and distilled from CaH 2 under an atmosphere of dry nitrogen. 1 H-NMR spectroscopy study was conducted with a Varian Mercury300 spectrometer using tetramethylsilane (TMS; δ = 0 ppm) as internal standard. Or 1 H and 13 C NMR spectra were measured on a Bruker ARX 300 spectrometer using tetramethylsilane (TMS; δ = 0 ppm) as internal standard. The Fourier transform infrared (FTIR) spectra were recorded on a PerkinElmer-2 spectrometer in the region of 3000–400 cm-1. UV-visible spectra were obtained using a Shimadzu UV-2550 spectrometer. Elementary analysis was taken on a Vario EL III elementary analysis instrument. Gel permeation chromatography (GPC) was used to determine the molecular weights of polymers. GPC analysis was

performed on an Agilent 1100 series HPLC system and a G1362A refractive index detector.
Polystyrene standards were used as calibration standards for GPC.THF was used as an eluent and the flow rate was 1.0 mL/min.Photoluminescence spectra were performed on a Hitachi F-4500 fluorescence spectrophotometer.

Synthesis of P0
Into a baked 80-mL Schlenk tube with a stopcock in the sidearm was added 1.14 g of monomer S1.The tube was evacuated under vacuum and then flushed with dry nitrogen three times through the side arm.Freshly distilled toluene (16 ml) was injected into the tube to dissolve the monomer.

Preparation of Polymer Thin Films.
The polymers were dissolved in ethanol (concentration ~3 wt %) and the solutions were filtered through syringe filters.Polymer films were spin-coated onto glass substrates, which were cleaned by N, N-dimethyformide, acetone, distilled water and THF sequentially in ultrasonic bath before use.
Residual solvent was removed by heating the films in a vacuum oven at 40 o C.

Preparation of solutions.
Preparation of solutions of metal ions and anions 0.2 mmol of each inorganic salt (NaNO 3 , 17.0 mg; KNO 3 , 20.2 mg; Ba(NO 3 ) 2 , 52.3 mg; AgNO 3 , was dissolved in distilled water (10 mL) to afford 2×10 -2 mol/L aqueous solution.The stock solutions could be diluted to desired concentration with water when needed.
Preparation of polymer solutions P1 (2.1 mg) was dissolved in ethanol to afford the stock solution with the concentration of 1.06×10 -3 mol/L.This stock solution was diluted to 1.06×10 -4 mol/L and 0.528×10 -4 mol/L with ethanol.
P0 (1.9 mg) was dissolved in the mixture solvent (10 mL) of ethanol and DMF (1:1) to afford the stock solution with the concentration of 1.06×10 -3 mol/L.And this stock solution (1 mL) was diluted to 1.06×10 -4 mol/L with ethanol.
P0 (1.9 mg) and imidazole (0.72 mg) were dissolved in the mixture solvent (10 mL) of ethanol and DMF (1:1) to afford the stock solution with the concentration of 1.06×10 -3 mol/L.And this stock solution (1 mL) was diluted to 1.06×10 -4 mol/L with ethanol.a The concentration of the metal ions were changed to 2×10 -2 mol/L.

Fluorescence intensity changes of the mixture of P0 and imidazole with metal ions
A solution of the mixture of P0 and imidazole (1.06×10 -4 mol/L) was prepared in ethanol.The solutions of metal ions (2×10 -2 mol/L) were prepared in distilled water.A solution of the mixture of P0 and imidazole (3.0 mL) was placed in a quartz cell (10.0 mm width) and the Fluorescence spectrum was recorded.The ion solution was introduced (4 μL) and fluorescence intensity changes were recorded at room temperature every time (Excitation wavelength: 335 nm).

Fluorescence intensity changes of P1+ Cu 2+ with other anions
A solution of P1 (0.528×10 -4 mol/L) was prepared in ethanol.The solutions of anions (2×10 -2 mol/L) were prepared in distilled water.A solution of P1 (3.0 mL) was placed in a quartz cell (10.0 mm width) and the Fluorescence spectrum was recorded.The ion solution was introduced (10 μL) and fluorescence intensity changes were recorded at room temperature every time (Excitation wavelength: 335 nm).

Fluorescence "turn off-turn on" of polymer film by ammonia
Fluorescence intensity change was recorded after the film of P1 immersed in aqueous Cu(NO 3 ) 2 solution (2×10 -2 mol/L).Then the film was immersed in ammonia aqueous solution and fluorescence intensity change was recorded at room temperature (Excitation wavelength: 335 nm).

Fluorescence "turn off-turn on" of polymer film by CN -
Fluorescence intensity change was recorded after the film of P1 immersed in aqueous Cu(NO 3 ) 2 solution (2×10 -2 mol/L).Then the film was immersed in NaCN aqueous solution (1.4×10 -3 or 1.0×10 -2 mol/L) and fluorescence intensity changes were recorded at room temperature each time (Excitation wavelength: 335 nm).
Scheme 1 of x , y and molar molecular weight of P1 was calculated according to the results of Elementary Analysis.EA: Found: C 73.09, H 6.620, N 9.015.(2×14.01)y/(210.27y+178.66x)×100% = 9.015% x = 0.36 x+y = 1 y = 0.64 Mw (per unit)=210.27×0.64+178.66×0.36=198.89Fluorescence intensity changes of P1 with metal ions A solution of P1 (1.06×10 -4 mol/L) was prepared in ethanol.The solutions of metal ions (2×10 -2 mol/L) were prepared in distilled water.A solution of P1 (3.0 mL) was placed in a quartz cell (10.0 mm width) and the Fluorescence spectrum was recorded.The ion solution was introduced (4 μL) and fluorescence intensity changes were recorded at room temperature every time (Excitation wavelength: 335 nm).Fluorescence titration of P1 with metal ionsA solution of P1 (1.06×10 -4 mol/L) was prepared in ethanol.The solutions of metal ions were prepared in distilled water.A solution of P1 (3.0 mL) was placed in a quartz cell (10.0 mm width) and the Fluorescence spectrum was recorded.The ion solution was introduced in portions and fluorescence intensity changes were recorded at room temperature every time (Excitation