Synthesises And Study Of Crystal Chemistry On Several Kinds Of Azo Compounds

A number of azo compounds, containing donor-acceptor groups, have been synthesized and the single crystals were grown by slow evaporation at ambient temperature. Their crystal structures are determined by X-Ray analysis.In our database there are a total of 108 compounds of azobenzenes, of which 102 were retrieved from the CSD (Cambridge Structure Database) using searching program and 6 were determined by us. From the database, five classes of compounds were studied. Using our program CSD2OPEC, we first decode the format of CSD. Then the crystal model and the packing energy were calculated using the program OPECH. Using our program GC, geometrical parameters and symmetrical relations were obtained. In this thesis, we analyzed the crystal structure of a series of azo compounds and systematically studied the effects of configuration, resonance, planarity of molecule and intermolecular interactions on their packing and properties, and drew the following conclusions.1) The position of substituentes and different substituents have an important effect on molecular planarity.2) If molecules can form indefinite chains by strong intermolecular hydrogen bonds, the hydrogen bonds action will be the most important factor in molecule packing.3) In the crystal structures where the strong formation groups of hydrogen bonds lack, weak interactions play important roles in the molecular self-assembling into crystal.4) If the planarity of the molecules is good, it/n interaction results in molecular stacking in crystal.5) All of-NO2 groups take part in hydrogen bonds. And most of them are bifurcative.6) When the substituents are long-chained alkyl radicals, lacking n/n interaction, alkyl-alkyl action between two molecules will affect the crystal staking.7) In molecules in which intramolecular resonance assisted hydrogen bonds (RAHB), the planarity of the molecule is significantly strengthened through the resonance hydrogen bonds.