Ab initio approaches based on density functional theory (DFT) are a reliable way to predict electronic and atomic structures. However, their high computational cost limits the possibility of modeling metal complexes with ligands of high molecular weight. Although DFT-based ab initio molecular dynamics (AIMD) simulations allow access to the dynamical properties of small molecular systems of fewer than 1000 atoms for several hundred picoseconds, AIMD simulations with tens of thousands of atoms for nanoseconds is outside the realms of possibility due to the high computational cost involved. For this reason, classical molecular dynamics (CMD) simulations using accurate force-field parameters are desirable, and they can be a fundamental approach to simulating lanthanide complexes coordinated to ligands with high molecular weight.