Ligands affect catalytic activity in several ways: - Electronic Effects: Ligands can donate or withdraw electron density from the central metal atom, altering its reactivity. - Steric Effects: The size and shape of ligands can influence the accessibility of the active site, impacting how substrates interact with the catalyst. - Solubility: Ligands can affect the solubility of the catalyst in various solvents, which is important for homogeneous catalysis. - Stability: Ligands can enhance the stability of the catalyst, preventing degradation during the reaction.