Solvothermal synthesis. Bi2I6(L′)2 ( ). The reaction was carried out using the solvothermal synthesis method. BiI3 (57 mg, 1 eq., 0.81 mmol), ligand (30 mg, 1 eq., 0.81 mmol) and 9 mL anhydrous acetonitrile were loaded into a 25 mL Teflon-lined stainless-steel autoclave. The autoclave was sealed and heated slowly over 6 hours to 150 °C and then kept at same temperature for 120 hours. The oven was cooled slowly to room temperature (35 °C) over 120 hours. After the reaction was completed, the orange-colored small crystals settled in the reaction mixture and were filtered off, and washed with diethyl ether. The complex was further dried in the vacuum oven at