Synthesis and Characterization of K2[Ni(CN)4] , K3[Fe(C2O4)3] and Cu(acac)2 Complexes :: Lab Report

Synthesis and Characterization of K2[Ni(CN)4] , K3[Fe(C2O4)3] and Cu(acac)2 complexes(IV , V and VI) with different structures and Properties 1. Introduction The 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 done on each of the 3 synthesized complexes by obtaining their UV-Vis spectrum. The UV-Vis spectrum of each complex would identify different properties and would help to explain the observations made when they were synthesized (for example their colour and how they reacted). 2. Method Table 1: Synthesis of K2[Ni(CN)4] Amount of Reagents used Method Observations NiSO4 †¢ 7H2O : 6.00 g KCN : 3.01g In 20ml water NiSO4 †¢ 7H2O was dissolved and the solution containing KCN (dissolved in 7ml 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 solution of KCN (dissolved in 3ml of water). This solution was heated and swirled so that the crystals that formed dissolved. It was heated again and left so that crystals started forming again. This solution was then placed in an ice bath to enhance crystallization and the crystals were removed by filtration. The water was removed by drying the crystals in the oven at 100 °C. A small amount of the sample was dissolved in water and the UV-Vis spectrum was obtained. Nickel (II) sulphate hexahydrate was used in place of heptahydrate. When the precipitate was added to the KCN solution, it turned dark red. As it was heated it darkened even more but as the crystals started forming the colour changed to a light red. As the crystals dried more its colour changed from light red-orange to a light yellow colour. These crystals were dissolved in water for the UV-vis spectrum. The solution was a yellow colour. Table 2: Synthesis of K3[Fe(C2O4)3] Amount of Reagents used Method Observations (NH4)2Fe(SO4)2 †¢ 6H2O: 5.03g To a solution of (NH4)2Fe(SO4)2 †¢ 6H2O (dissolved in 20ml water) 1 ml of sulphuric acid was added and stirred. The oxalic acid (dissolved in 25ml water) was also added and this combined solution was slowly heated to boiling, resulting in the formation of yellow iron(II) oxalate precipitate. The liquid was decanted and 15ml of hot water was added again 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 10ml hot water) was added.