Table of Contents

Abstract: Ab initio and density functional theory methods have been applied to study the molecular structure and interaction of water with N-methyl-2-propenylidenimine and Nmethyl- 2-butenylidenimine molecules. The most possible reactive sites of the above molecules have been identified for the water interactions. The strength of the hydrogen bond is discussed using the atomic charges, which were calculated using the Mulliken population analysis and Natural population analysis schemes at MP2/6-31G* level of theory. The electron density (ρ) and laplacian of electron density (∇²ρ) have been calculated for the possible existence of the hydrogen bonds with CH and CH3 groups of molecules using the “Atoms in molecules” approach. The chemical hardness and chemical potential for these complexes have been calculated at HF/6-31G* level of theory and discussed for the conformational stability of these molecules.

Abstract: Fundamental molecular issues in lubrication chemistry were reviewed under categories of solution chemistry, contact chemistry and tribochemistry. By introducing the Density Functional Theory(DFT)-derived chemical reactivity parameters (chemical potential, electronegativity, hardness, softness and Fukui function) and related electronic structural principles (electronegativity equalization principle, hard-soft acid-base principle, and maximum hardness principle), their relevancy to lubrication chemistry was explored. It was suggested that DFT, theoretical, conceptual and computational, represents a useful enabling tool to understand lubrication chemistry issues prior to experimentation and the approach may form a key step in the rational design of lubrication chemistry via computational methods. It can also be optimistically anticipated that these considerations will gestate unique DFT-based strategies to understand sophisticated tribology themes, such as origin of friction, essence of wear, adhesion in MEMS/NEMS, chemical mechanical polishing in wafer manufacturing, stress corrosion, chemical control of friction and wear, and construction of designer tribochemical systems.