<p>To facilitate computational investigation of intermolecular interactions in the solution phase, we report the development
of ALMO-EDA(solv), a scheme that allows the application of continuum solvent models within the framework of
energy decomposition analysis (EDA) based on absolutely localized molecular orbitals (ALMOs). In this scheme, all
the quantum mechanical states involved in the variational EDA procedure are computed with the presence of solvent
environment so that solvation effects are incorporated in the evaluation of all its energy components. After validation on
several model complexes, we employ ALMO-EDA(solv) to investigate substituent effects on two classes of complexes
that are related to electrochemical CO<sub>2</sub>
reduction catalysis. For [FeTPP(CO<sub>2</sub>−κC)]<sup>2−</sup>
(TPP = tetraphenylporphyrin), we
reveal that two ortho substituents which yield most favorable CO2
binding, −N(CH<sub>3</sub>)<sub>3</sub><sup>+</sup> (TMA) and −OH, stabilize the
complex via through-structure and through-space mechanisms, respectively. The Coulombic interaction between the
positively charged TMA group and activated CO<sub>2</sub>
is found to be largely attenuated by the polar solvent. Furthermore, we
also provide computational support for the design strategy of utilizing bulky, flexible ligands to stabilize activated CO<sub>2</sub>
via long-range Coulomb interactions, which creates biomimetic solvent-inaccessible “pockets” in that electrostatics is
unscreened. For the reactant and product complexes associated with the electron transfer from the <i>p</i>-terphenyl radical
anion to CO<sub>2</sub>
, we demonstrate that the double terminal substitution of <i>p</i>-terphenyl by electron-withdrawing groups
considerably strengthens the binding in the product state while moderately weakens that in the reactant state, which are
both dominated by the substituent tuning of the electrostatics component. These applications illustrate that this new
extension of ALMO-EDA provides a valuable means to unravel the nature of intermolecular interactions and quantify
their impacts on chemical reactivity in solution.<br></p>
Energy decomposition analysis for exciplexes using absolutely localized molecular orbitals
