Blue M2: an intermediate melanoidin studied via conceptual DFT

Area of Science:

• Computational chemistry
• Theoretical chemistry
• Materials science

Background:

• Melanoidin pigments are complex macromolecules formed during the Maillard reaction.
• Understanding the molecular structure and properties of melanoidin intermediates is crucial for controlling their characteristics.
• Computational methods offer a pathway to investigate these complex systems.

Purpose of the Study:

• To computationally evaluate the performance of ten density functionals for predicting the molecular properties and structure of the blue-M2 intermediate melanoidin pigment.
• To identify the most suitable density functionals for characterizing the chemical reactivity of this pigment.
• To accurately predict the maximum absorption wavelength of the blue-M2 intermediate.

Main Methods:

• Utilized ten density functionals (CAM-B3LYP, LC-ω PBE, M11, M11L, MN12L, MN12SX, N12, N12SX, ω B97X, ω B97XD) with the Def2TZVP basis set.
• Employed the SMD solvation model to account for solvent effects.
• Calculated chemical reactivity descriptors using conceptual density functional theory (DFT).
• Identified active sites for nucleophilic, electrophilic, and radical attacks using Fukui functions, electrophilic Parr functions, and condensed dual descriptors.

Main Results:

• The study accurately predicted the maximum absorption wavelength of the blue-M2 intermediate compared to experimental data.
• MN12SX and N12SX density functionals demonstrated superior performance in predicting chemical reactivity.
• The Fukui function, electrophilic Parr functions, and condensed dual descriptors effectively identified active sites for various chemical attacks.

Conclusions:

• MN12SX and N12SX density functionals are recommended for future computational studies on blue-M2 intermediate melanoidin pigment.
• Conceptual DFT provides valuable insights into the chemical reactivity and active sites of melanoidin pigments.
• Computational modeling is a powerful tool for understanding complex pigment systems.