Attochemistry of hydrogen bonded amide and thioamide model complexes in protein following vertical ionization

Abstract

Hydrogen bond in protein structure is a dynamic topic in research community. 2-Pyridone attached to amide forms hydrogen bond in the protein structure. Instead of amide, a number of model complexes such as thioamide in protein structure are used in recent research. Thioamide behaves potential surrogate of amide. To develop better understanding on the effect of ionizing radiation in protein, charge migration should be studied rigorously for the hydrogen bonded complexes such as amide:2-pyridone or thioamide:2-pyridone complexes. Hydrogen bond energies of these complexes are investigated in this context. Surprisingly, thioamide hydrogen bonded complexes are stronger in nature compare to amide hydrogen bonded complexes. This investigation centered on charge migration through amide and thioamide hydrogen bonded complexes and focused on different aspects of attosecond charge migration through these bonds. It is observed that charge migration occurs in amide hydrogen bonded complexes in 600–800 attoseconds time scale whereas it ceases for thioamide hydrogen bonded complexes.