Synthesis and characterization of the complexes K2[Ni(CN)4], K3[Fe(C2O4)3] and Cu(acac)2 (IV, V and VI) with different structures and properties1. IntroductionThe aim of this experiment was to synthesize HgCo(SCN)4, [Ni(en)3]S2O3, NiCl2(PPh3)2, K2[Ni(CN)4], K3[Fe(C2O4)3] and Cu(acac ) 2 but only K2[Ni(CN)4], K3[Fe(C2O4)3] and Cu(acac)2 were synthesized and explained in this report. Characterization was then carried out on each of the 3 synthesized complexes, obtaining the UV-Vis spectrum. The UV-Vis spectrum of each complex would identify different properties and help explain observations made at the time of synthesis (e.g. their color and how they reacted).2. MethodTable 1: Synthesis of K2[Ni(CN)4]Quantity of reagents used Method ObservationsNiSO4 • 7H2O: 6.00 gKCN: 3.01 g In 20 ml of water NiSO4 • 7H2O was dissolved and the solution containing KCN (dissolved in 7 ml of water) was added to the nickel solution. This solution was filtered and the precipitate was washed with small quantities of water. This precipitate was added to the KCN solution (dissolved in 3 ml of water). This solution was heated and swirled so that the crystals that formed dissolved. It was heated again and left so that the crystals began to form again. This solution was then placed in an ice bath to aid crystallization and the crystals were removed by filtration. Water was removed by drying the crystals in an oven at 100°C. A small amount of the sample was dissolved in water and the UV-Vis spectrum was obtained. Nickel(II) sulfate hexahydrate was used instead of the heptahydrate. When the precipitate was added to the KCN solution, it turned dark red. As it was heated, it darkened even more, but as crystals began to form the color changed to light red. As the crystals dried more, the color changed from light orange-red to light yellow. These crystals were dissolved in water for the UV -vis spectrum. The solution was yellow in color. Table 2: Synthesis of K3[Fe(C2O4)3]Quantity of reagents used Method Remarks(NH4)2Fe(SO4)2 • 6H2O: 5.03 g A a solution of (NH4)2Fe(SO4) 2 • 6H2O (dissolved in 20 ml of water), 1 ml of sulfuric acid was added and stirred. Oxalic acid (dissolved in 25 mL of water) was also added and this combined solution was slowly heated to boiling, resulting in the formation of a yellow iron(II) oxalate precipitate. The liquid was decanted and 15 ml of hot water was again added to the precipitate, this was stirred and filtered. The precipitate (iron(II) oxalate) was transferred to another beaker and a potassium oxalate solution (dissolved in 10 ml of hot water) was added).