Structure-energy relationship inω-amino acids and related compounds

Area of Science:

• Computational chemistry
• Molecular modeling
• Organic chemistry

Background:

• Ab-initio RHF calculations have been used to study potential energy surfaces of various molecules.
• A unified approach is needed to describe the conformational energies of related molecules like amino acids, hydroxy acids, and amino alcohols.

Purpose of the Study:

• To develop a common energy function applicable to omega-amino acids, omega-hydroxy acids, and omega-amino alcohols.
• To create a method for predicting conformational energies based on essential dihedral angles.
• To assess the influence of intramolecular interactions, such as hydrogen bonding, on conformational energy.

Main Methods:

• Developed an energy function dependent on essential dihedral angles for molecular framework description.
• Employed a least-squares fit procedure to determine the energy function parameters.
• Implemented a threshold for correlation coefficients to filter out geometries with unfavorable contributions.
• Compared energies calculated by quantum chemistry with those estimated by the developed function.

Main Results:

• The energy function accurately predicted energies for geometries used in parameter fitting.
• Larger energy differences were observed for geometries omitted from the fitting process.
• For conformers with intramolecular hydrogen bonding, energy differences approximated predicted H-bond interaction energies.

Conclusions:

• The developed energy function provides a semi-quantitative measure of conformational energy.
• The method effectively captures the influence of intramolecular interactions, particularly hydrogen bonding.
• This approach offers a computationally efficient way to study molecular conformations and interactions.