This thesis deals with the investigation of structural properties of many different
systems via Electronic Circular Dichroism (ECD). The interpretation of experimental
data has been carried out mainly with quantum-chemistry methods, such as Density
Functional Theory (DFT), on both solution and solid-state systems.
The analysis of solution systems is oriented towards applications on biologically
active compounds, both natural or synthetic, and its objective is to underline the key
role of these approaches in the determination of the absolute configuration and the
difficulties that may be encountered in case of flexible molecules. Solid-state
measurements represent an attractive alternative to these cases where a lot of
conformations are present, but difficulties in the interpretation of the signals due to
solid-state interactions which are not observable in solution may be faced.
For a better understanding of spectral lineshapes, more detailed analyses have been
performed taking into account vibronic effects, which may also assist in the
determination of the conformational situation of the investigated substrate. The
limitations of the vibronic treatment for coupled electronic states have been considered,
leading to a general all-coordinate approach which allows simulating the electronic
spectrum of “dimeric” molecules with weakly coupled electronic states through a time dependent
approach
