Synthesis of CoPOM. The CoPOM complex was synthesized using a slightly modified literature route. Briefly, NaWO4•2H2O (35.62 g, 0.108 mol), Na2HPO4•7H2O (1.70 g, 0.012 mol) and Co(NO3)2•6H2O (6.98 g, 0.024 mol) were dissolved in 100 mL deionized water in a 200 mL round-bottom flask. After adjusting the pH to 7 using 9 M aqueous HCl solution under magnetic stirring, the purple suspension was stirred and refluxed at 105°C bath temperature for 2 hours. After reflux, the solution was saturated with 36 g NaCl and allowed to cool to room temperature. The resulting purple crystals were collected, quickly washed with approximately 30 mL of water, and recrystallized from hot water. The purity of CoPOM is confirmed by Fourier transform infrared spectroscopy (FT-IR).