Electronic structure theory based study of proline interacting with gold nano clusters

Area of Science:

• Computational chemistry
• Materials science
• Nanotechnology

Background:

• Metal nanoparticle-biomolecule interactions are key for biosensor design.
• Proline-gold nanocluster interactions are explored for their potential in biosensing applications.

Purpose of the Study:

• To investigate the structural, electronic, and bonding properties of proline tagged with gold nanoclusters using computational methods.
• To understand the nature and stability of these complexes for future biosensor development.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Geometries were optimized using PBE1PBE functional and a mixed basis set (6-311++G for proline, SDD for gold clusters).
• Analysis included interaction energies, molecular orbitals, charge density, electron affinity, ionization potential, and Natural Bond Orbital (NBO) analysis.

Main Results:

• Complexes with odd numbers of gold atoms exhibited higher stability.
• Complexation led to a significant decrease in HOMO-LUMO gaps.
• Key interactions include N-Au and O-Au bonds, alongside non-covalent interactions.
• Electron affinity and ionization potential increased upon complexation.
• NBO analysis confirmed partial covalent character due to charge transfer from proline to the gold cluster.

Conclusions:

• The interaction between proline and gold nanoclusters is partially covalent, with specific bonding and non-covalent contributions.
• The electronic properties of gold nanoclusters are significantly altered by proline complexation.
• These findings provide valuable insights for experimental studies and future applications in biosensing technology.