Excited-State Solvation Structure of Transition Metal Complexes from Molecular Dynamics Simulations and Assessment of Partial Atomic Charge Methods

• Main Authors: Abedi, Mostafa, Levi, Gianluca, Zederkof, Diana B, Henriksen, Niels E, Pápai, Mátyás, Møller, Klaus B
• Format: Journal Article
• Language: English
• Published: 21-12-2018
• Subjects: Physics - Chemical Physics
• DOI: 10.48550/arxiv.1812.09090

Phys. Chem. Chem. Phys., 2019 In this work, we investigate the excited-state solute and solvation structure
of $\mathrm{[Ru(bpy)_3]^{2+}}$, $\mathrm{[Fe(bpy)_3]^{2+}}$,
$\mathrm{[Fe(bmip)_2]^{2+}}$ and $\mathrm{[Cu(phen)_2]^{+}}$
(bpy=2,2'-pyridine; bmip=2,6-bis(3-methyl-imidazole-1-ylidine)-pyridine;
phen=1,10-phenanthroline) transition metal complexes (TMCs) in terms of
solute-solvent radial distribution functions (RDFs) and evaluate the
performance of some of the most popular partial atomic charge (PAC) methods for
obtaining these RDFs by molecular dynamics (MD) simulations. To this end, we
compare classical MD of a frozen solute in water and acetonitrile (ACN) with
quantum mechanics/molecular mechanics Born-Oppenheimer molecular dynamics
(QM/MM BOMD) simulations. The calculated RDFs show that the choice of a
suitable PAC method is dependent on the coordination number of the metal,
denticity of the ligands, and type of solvent. It is found that this selection
is less sensitive for water than ACN. Furthermore, a careful choice of the PAC
method should be considered for TMCs that exhibit a free direct coordination
site, such as $\mathrm{[Cu(phen)_2]^{+}}$. The results of this work show that
fast classical MD simulations with ChelpG/RESP or CM5 PACs can produce RDFs
close to those obtained by QM/MM MD and thus, provide reliable solvation
structures of TMCs to be used, e.g. in the analysis of scattering data.