Energies of polypeptides: theoretical conformational study of polyglycine using quantum mechanical partitioning.

A quantum-mechanical investigation of functional group effect on 5,5'-disubstituted-1,1'-azobis(tetrazoles)

The present work reports the detailed B3LYP/6-311++G(d,p) study of most stable transand cisconfigurations photoisomerization in the core system of computational photochemistry-the 5,5'-disubstituted-1,1'-azobis (tetrazole) molecules. All computations were carried out in gas phase attemperature 293.15 K and pressure 1 atm. Firstly; the potential energy surface (PES) of the groundstate of the mol...

Raman studies of solution polyglycine conformations.

Polyglycine (polygly) is an important model system for understanding the structural preferences of unfolded polypeptides in solution. We utilized UV resonance and visible Raman spectroscopy to investigate the conformational preferences of polygly peptides of different lengths in water containing LiCl and LiClO(4). Lithium salts increase the solubility of polygly. Our study indicates that in sol...

A Theoretical Study on Applying Conformational Analysis of 2-Halo-2-Oxo-1,3,2-Dioxaphosphorinanes

The quantum-chemical calculations on the conformational properties of 2-flouro-2-oxo- 1,3,2-dioxaphosphorinane (1), 2-choloro-2-oxo-1,3,2-dioxaphosphorinane (2) and 2-bromo- 2-oxo-1,3,2-dioxaphosphorinane (3) have been investigated by means of ab initio molecular orbital (HF/6-311+G**) and hybrid density functional theory (B3LYP/6-311+G**) based methods and Natural Bond Orbital (NBO) interpreta...

Quantum Mechanical Study of the Structure, NBO and HOMO–LUMO Analysis of Molecule Oxaliplatinium

Oxaliplatinium is an anticancer drug, used in chemotherapy. To investigate the oxaliplatinium structure based on frontier orbital analysis, thermodynamic analysis and natural bond orbital (NBO) theory is the main objective of the present research. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The NBO charges, the values of electric dipole moment (µ) of ...

A quantum-mechanical study on nitro and amino derivatives of 1,2,3,4-tetrazine