Quantum Chemical Computation Of Intermolecular Interactions Of Coal Supramolecular Molecules

The intermolecular interactions a nd m olecular recognition of coal are key components of coal supramolecular chemistry. By the theoretic studies on intermolecular interactions of coal molecular, we may understand the m olecular recognition mechanism of coal supramolecular molecules, and then disclosure the characterization of coal supramolecular molecules, to supply theoretical basis for the abundance of coal structural theory and the development of coal molecular engineering subject. We study the coal intermolecular interactions by quantum chemistry theoretic methods in this paper.The parallel and T-shaped configurations of OH self-associated hydrogen bond is studied by ab intio HF method at 6-31*basis set. The T-shaped optimized configuration is more stable than parallel optimized configuration by energy analysis, and its energy is -10.80kj/mol by 6-311G/RHF,MP2 method and BSSE corrected. The r esult s hows t his h ydrogen b ond isaw eakly h ydrogen b ond system.The hydrogen bond in coal is studied by HF/MP2 method on 6-31G+ basis set, and get their optimized configurations. These hydrogen bonds accept the same stable order after energy and thermodynamic analysis, that is cyclic OH hydrogen bond > OH-N hydrogen bond > OH-ether hydrogen bond > OH self-associated > OH- hydrogen bond.The - stacking interactions are studied by DFT method on B3LYP/6-31G+ level, and get result of energy of parallel optimized configuration is -16.87kj/mol by single-point energy computing on 6-31G(d,p) basis set, and the system intermolecular interactions is relatively weak.The intermolecular interactions of coal big molecularconstruction unit are researched by theoretic study on DFT-B3LYP/3-21G level, and get the intermolecular interactional energy is -61.05kj/mol on 6-31G basis set. The energy shows that this intermolecular interactions is relatively weak.