1 vinylimidazole

1-Vinylimidazole and potassium hexafluorophosphate (KPF₆) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Iron(iii) chloride hexahydrate (FeCl₃·6H₂O), iron(ii) chloride tetrahydrate (FeCl₂·4H₂O), ammonia, tetraethyl orthosilicate (TEOS), 1-vinyltriethoxysilane (VTES), 2,2′-azobisisobutyronitrile (AIBN), 1-bromooctane and triethylamine were obtained from Merck Chemicals (Darmstadt, Germany). HPLC grades of methanol, acetonitrile, acetone, potassium dihydrogen phosphate and sodium dodecyl sulfate were acquired from Merck (Darmstadt, Germany). Standards of CANA and EMPA were supplied from MSN Life Science Private Limited Unit-2, (India) and Emeishan Hongsheng Pharmaceutical Co. (China), respectively. Standard of MET kindly donated by Mahban Chemi Co. (Tehran, Iran). Fixed-dose combination Invokamet tablets (50 mg CANA/500 mg MET) and Jardiance tablets (25 mg EMPA) were purchased from Janssen (USA). Fresh plasma samples were obtained from Iranian Blood Transfusion Organization (Tehran, Iran) and stored at −18 °C until being used. Ultrapure water (Millipore, Bedford, MA, USA) was used throughout the whole experiments.

As an intermediate for the VAI-TFSI, 1-vinyl-3-allyl-imidazolium bromide (VAI-Br) was synthesized. 10.0 mmol of 1-vinylimidazole (Sigma-Aldrich) was mixed with 50 mL of acetonitrile (Sigma-Aldrich) and 12.0 mmol of allyl bromide (Sigma-Aldrich). Then, the acetonitrile was eliminated by rotary evaporator and the resulting crude product was purified by decantation using 20 mL of ethyl acetate and 20 mL of diethyl ether, respectively. The obtained 7.5 mmol of VAI-Br was dissolved in 50 mL of deionized water. Subsequently, 7.5 mmol of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added in the solution. The resulting mixture was then extracted using 100 mL of dichloromethane and was further purified by extraction with 50 mL of deionized water to remove organic impurities remaining in the solution. The obtained dichloromethane layer was purified by short-column chromatography using neutral aluminum oxide and the dichloromethane was removed by rotary evaporator. The obtained VAI-TFSI was dried overnight in a vacuum oven. The chemical structure of the VAI-TFSI was confirmed using ¹H-NMR spectroscopy.