The photochemical properties of cis-[Co en 2Cl2]+ where en = ethylenediamine involve the absorption of light energy, which can induce changes in the electronic configuration of the complex. This can lead to the formation of new products through a process called photoisomerization.The photochemical reaction mechanism for cis-[Co en 2Cl2]+ is as follows:1. Absorption of light: When the cis-[Co en 2Cl2]+ complex absorbs light, it undergoes a transition from its ground state to an excited state. This is due to the promotion of an electron from a lower-energy d-orbital to a higher-energy d-orbital.2. Isomerization: In the excited state, the complex can undergo isomerization, which involves the rearrangement of its ligands. In this case, the cis-[Co en 2Cl2]+ complex can isomerize to its trans isomer, trans-[Co en 2Cl2]+. This process is known as photoisomerization.3. Relaxation: After the isomerization, the complex returns to its ground state by releasing the absorbed energy in the form of heat or light fluorescence or phosphorescence . This results in the formation of the trans isomer as the final product.The main product formed in this photochemical reaction is the trans isomer, trans-[Co en 2Cl2]+. This isomerization can have significant effects on the chemical and physical properties of the complex, such as changes in its reactivity, color, and magnetic properties. The photoisomerization of cis-[Co en 2Cl2]+ to trans-[Co en 2Cl2]+ is an example of how light energy can be used to control the structure and properties of coordination complexes.