The effect of various metals on the photochemical properties of metal complexes under UV irradiation can be quite significant. Different metals can alter the excited state lifetime, reactivity, and other properties of the complexes, leading to different photochemical behaviors. Some of the factors that can be influenced by the choice of metal include:1. Electronic configuration: The electronic configuration of the metal ion can have a significant impact on the photochemical properties of the complex. For example, metal ions with d0 or d10 configurations e.g., Ti IV , Zn II often exhibit relatively short excited state lifetimes and low reactivity, while metal ions with partially filled d orbitals e.g., Ru II , Ir III can have longer excited state lifetimes and higher reactivity.2. Ligand field strength: The strength of the ligand field around the metal ion can also affect the photochemical properties of the complex. Strong-field ligands e.g., CO, CN- can lead to low-energy, long-lived excited states, while weak-field ligands e.g., H2O, Cl- can result in higher-energy, short-lived excited states. This can influence the reactivity of the complex and the types of photochemical reactions that can occur.3. Spin state: The spin state of the metal ion can also play a role in determining the photochemical properties of the complex. For example, high-spin metal ions e.g., Fe II , Co II can have short excited state lifetimes and low reactivity, while low-spin metal ions e.g., Fe III , Co III can have longer excited state lifetimes and higher reactivity.4. Coordination geometry: The coordination geometry of the metal complex can also influence its photochemical properties. For example, octahedral complexes often exhibit longer excited state lifetimes and higher reactivity than tetrahedral complexes, due to the greater number of possible excited states and the larger spatial separation between the metal ion and the ligands.5. Redox properties: The redox properties of the metal ion can also affect the photochemical behavior of the complex. Metal ions with more positive reduction potentials e.g., Au III , Pt IV can undergo photoinduced electron transfer reactions more readily than metal ions with less positive reduction potentials e.g., Cu I , Ag I .In summary, the choice of metal can have a significant impact on the photochemical properties of metal complexes under UV irradiation. By carefully selecting the appropriate metal ion and ligands, it is possible to tune the excited state lifetime, reactivity, and other properties of the complex to achieve the desired photochemical behavior.