What aspect of solvatochromism indicates stronger metal/ligand interactions?

The transition frequency changes are indicative of the strength of metal/ligand interactions in solvatochromism because they reflect the energy difference between the ground and excited states of a complex influenced by its environment. When the solvent polarity changes, it can stabilize or destabilize certain electronic states of the metal-ligand complex. A shift in transition frequency typically occurs due to changes in the dielectric constant and solvation effects that impact the electronic structure of the metal center or ligand. Stronger interactions between the metal and ligand will generally result in a more significant change in transition frequency, signifying that the complex's electronic properties are being affected by the solvate environment.

Other factors such as the size of the solvent molecules, temperature of the solution, and polarity of the solvent do play a role in solvatochromism but are not as directly tied to the strength of metal/ligand interactions as the transition frequency changes. While larger solvent molecules can have steric effects and temperature can affect solubility and kinetics, the specific energetic changes and their relation to electronic transitions are best characterized by shifts in transition frequencies. Likewise, while solvent polarity influences the solvation and stability of the electronic states, the most direct evidence of stronger metal/ligand interactions is seen through the