Materials and Instrumentation
All chemicals were purchased from Merck or Aldrich. Characterization of the new [email protected] (1) was performed by FESEM (TESCAN-MIRA3), TEM (Philips EM 208S), FTIR (Shimadzu 8400S), BET (ASAP 2020 micromeritics), and TGA Bahr Company STA 504). XRD patterns of the mesoporous silica nanosphere were obtained using TW 1800 diffractometer with CuKa radiation (λ = 1.54050 Å). 1H NMR (500 MHz, Bruker DRX-500 Avance spectrometers in DMSO) spectral were compared with those obtained from authentic samples or reported in the literature. Distilled water was used in all experiments.
General procedure for the preparation of 1,3-bis(3-(triethoxysilyl)propyl) urea bridge
First, (3-aminopropyl) triethoxysilane (APS, 6.52 mL) was added dropwise to 2,4-toluene diisocyanate (2 mL) and the mixture was stirred under solvent-free condition at 75 °C for 4 h. Then, the mixture was cooled down to room temperature and stirred for 12 h to obtain a white gel. Subsequently, CHCl3 (10 mL) was added to the white gel and a clear solution was obtained, then hexane (10 mL) was added to it and a white precipitate was obtained which was separated by filtration and washed with hexane and dried at 70 °C.
General procedure for the preparation of PMO
P123 (4 g) as a surfactant was dissolved in 150 mL HCl (2M) and heated to 40 °C under stirring for 4 h. Then, the white powder (3.5 g) prepared above was dissolved in CHCl3 and with TEOS (11.8 mL) added dropwise and simultaneously to the solution of P123 and HCl and stirred for 24 h at 40 °C and then aging for 48 h at 100 °C. Eventually, washed with EtOH (5 mL) and hexane (5 mL) and dried at 80 °C. The surfactant was extracted by a Soxhlet via EtOH-acidic. Finally, it was dried at 100 °C for 12 h.
General procedure for the preparation of [email protected] (1)
Cu(OAc)2 (0.5 g) was dissolved in 5 mL distilled water and this solution was added slowly to the suspension of PMO-APS-TDU (0.5 g) in 10 mL distilled water. The solution was stirred at room temperature for 24 h. Finally, the resulting solid was collected, washed with H2O and EtOH, and dried at 60 °C for 5 h (Scheme 3).
General procedure for the preparation of 2-(1H-Tetrazol-5-yl) acrylonitrile derivatives
[email protected] (1, 0.03 g), aromatic aldehyde (2a-i, 1 mmol), malononitrile (3, 1 mmol), and NaN3 (4, 1.20 mmol) were heated to 110 °C under solvent-free conditions. The reaction development was monitored by TLC. After completion of the reaction, the reaction mixture dissolved in HCl (2M, 15 mL) and the catalyst was separated by filtration, then the resulting solution was extracted with EtOAc (3×10 mL). Finally, the solvent evaporated under reduced pressure and the desired product was recrystallized with EtOH-H2O to afford the pure product. The recovered catalyst was reused for subsequent cycles without a loss of performance.
The FTIR, 1HNMR and 13CNMR data of tetrazole derivatives
3‑(2‑Chlorophenyl)‑2‑(1H‑tetrazole‑5‑yl) acrylonitrile (5b)
FTIR (KBr, cm-1): 3420 (NH), 2221 (CN), 1564 (C=C).; 1HNMR (500MHz, CDCl3): δ (ppm) 7.58–7.59 (2H, d, CH-Ar), 7.61–7.69 (1H, t, J= 7.20 Hz, CH-Ar), 8.13–8.14 (1H, d, CH-Ar), 8.54(1H, s, CH), 13.22 (br s, NH).; 13CNMR (75 MHz, CDCl3) δ (ppm) 80.14, 116.80, 129.17, 129.88, 130.73, 131.97, 134.39, 135.19, 147.04, 159.07, 161.37.
3‑(4‑Methoxyphenyl)‑2‑(1H‑tetrazole‑5‑yl) acrylonitrile (5g)
FTIR (KBr, cm-1): 3146 (NH), 2224 (CN), 1586 (C=C).; 1HNMR (500MHz, CDCl3): δ (ppm) 3.82 (3H, s, OCH3), 7.09–7.11 (1H, d, CH-Ar), 7.96–7.99 (1H, d, CH-Ar), 8.21 (1H, s, CH), 13.70 (br s, NH). 13CNMR (75 MHz, CDCl3) δ (ppm) 56.02, 93.70, 115.25, 116.55, 125.21, 132.61, 147.97, 155.85, 162.91.