Applicability studies for a novel alternative method for calculation of core electron binding energies (CEBEs) as new molecular descriptors in medicinal chemistry and related areas

• Grant number: 03/09007-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2004
• End date: January 31, 2005
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Yuji Takahata
• Grantee: Rudolf Kiralj
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 03/00075-9 - Development of an alternative mehod to calculate core electron binding energies (CEBEs) of molecules, and evaluation of its applicability in drug design, AP.TEM

Abstract

X-ray Photoelectron Spectroscopy (XPS) or Electron Spectroscopy for Chemical Analysis (ESCA) is a relatively new X-ray based spectroscopy. Experimental core-electron binding energies (CEBEs) for electrons defined by atomic number, principal and azimuthal quantum number, when measured by this technique, Show systematic variations depending on atom environment, presumably due to changes in the atom oxidation state and valence shell. Computational methodologies based on Density Functional Theory (DFT) and semi-empirical (HAM/3) approaches are able to reproduce well the CEBE shifts (CEBEs relative to standards) known as ESCA chemical shifts. The aim of this project is to investigate the usefulness of new methodology to calculate ESCA shifts (at DFT and HAM/3 level) in medicinal chemistry, QSAR/QSSPR studies and related areas. It is presumed that, due to valence electron density changes, calculated ESCA shifts can be related to molecular descriptors, (hetero)aromaticity indices, biological activity/toxicity, physico-chemical and spectroscopic properties, chemical reactivity and intermolecular interactions at quantitative level. To test this statement, carbon 1s and other shifts in benzene derivatives, polycyclic aromatic hydrocarbons, artemisinins, indole-3-acetic acid and HIV-1 protease inhibitors will be related to the aforementioned phenomena and parameters. (AU)