Methodological Approach Based on Structural Parameters, Vibrational Frequencies, and MMFF94 Bond Charge Increments...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate theoretical modeling of platinum compounds is crucial for understanding their chemical properties and applications.
• Platinum derivatives, including cisplatin, are vital in catalysis and medicine, necessitating reliable computational parameters.
• Existing computational methods may not consistently predict both structural and vibrational properties for platinum systems.

Purpose of the Study:

• To comprehensively benchmark various computational methods for platinum derivatives.
• To evaluate the suitability of different density functionals and basis sets for platinum systems.
• To develop and validate parameters for classical force fields, specifically bond charge increments (bci), for platinum.

Main Methods:

• Performed a benchmark study on five platinum derivatives (PtH, PtCl, [PtCl4]2-, [Pt(NH3)4]2+, cis-[Pt(NH3)2Cl2]) using 16 density functionals and Post-Hartree-Fock methods.
• Investigated 11 basis sets, comparing relativistic all-electron and RECP approaches.
• Derived and analyzed partial atomic charges (CHELPG) and bond charge increments (bci) for MMFF94 force field parameterization.

Main Results:

• No single method excelled at predicting both structural parameters and vibrational frequencies.
• CHELPG partial atomic charges showed slight fluctuations for Pt, consistent with its soft acid nature in cisplatin.
• Average calculated bci values effectively captured atomic charge variations, providing a good description of platinum's chemical environment.
• A Python tool for bci optimization was developed and made publicly available.

Conclusions:

• The choice of computational methodology significantly impacts the accuracy of predicted properties for platinum compounds.
• Bond charge increments (bci) derived from quantum chemical calculations offer a reliable way to parameterize classical force fields for platinum-containing systems.
• The developed bci optimization tool and methodology will enhance molecular docking simulations involving platinum ligands.