The photochemical properties of transition metal complexes differ significantly from those of non-transition metal complexes due to their unique electronic structures and crystal field splitting. Here are some key differences and explanations:1. Electronic transitions: Transition metal complexes exhibit d-d transitions, charge transfer transitions ligand-to-metal and metal-to-ligand , and spin-forbidden transitions. In contrast, non-transition metal complexes primarily exhibit -* and n-* transitions. The d-d transitions in transition metal complexes arise due to the partially filled d orbitals, which allow for electronic transitions within the d orbitals.2. Crystal field splitting: In transition metal complexes, the interaction between the metal ion and the ligands leads to the splitting of the d orbitals into different energy levels. This splitting is known as crystal field splitting and is influenced by the geometry of the complex and the nature of the ligands. Non-transition metal complexes do not exhibit crystal field splitting as they lack d orbitals. Crystal field splitting plays a crucial role in determining the photochemical properties of transition metal complexes, such as their color and reactivity.3. Absorption spectra: Due to the d-d transitions and crystal field splitting, transition metal complexes often exhibit broad absorption bands in the visible and near-UV regions, resulting in their characteristic colors. Non-transition metal complexes typically have narrower absorption bands and may not exhibit strong colors.4. Photoreactivity: Transition metal complexes can undergo various photochemical reactions, such as photoinduced electron transfer, energy transfer, and ligand substitution reactions. These reactions are facilitated by the unique electronic structures and crystal field splitting of the transition metal complexes. Non-transition metal complexes generally exhibit lower photoreactivity due to the absence of d orbitals and crystal field splitting.5. Spin states: Transition metal complexes can exist in different spin states high-spin and low-spin depending on the crystal field splitting and the nature of the ligands. The spin states can influence the photochemical properties of the complexes, such as their reactivity and magnetic properties. Non-transition metal complexes do not exhibit spin state variations as they lack d orbitals.In summary, the photochemical properties of transition metal complexes differ from those of non-transition metal complexes mainly due to their unique electronic structures, partially filled d orbitals, and crystal field splitting. These factors lead to distinct electronic transitions, absorption spectra, photoreactivity, and spin states in transition metal complexes compared to non-transition metal complexes.