Studies On The Crystal Structure And Supramolecular Forces Of Isoflavonoids

Supramolecular chemistry can be defined as "chemistry beyond the molecule" bearing on the organized entities of higher complexity that result from the association of two or more chemical species held together by intermolecular forces, such as hydrogen bond, π-π stacking interaction and electrostatic interaction. Supramolecular chemistry is an important extension of the chemical field. Its object is the multimolecular entities assembled by the weak no-covalence interaction between molecules. Supermolecules are to molecules and the intermolecular bond what molecules are to atoms and the covalent bond. The supramolecular recognition and self-assembly are the two content of the supramolcecular chemistry and the supramocleular forces are the core of them. Isoflavonoids are important natural second metabolizability product. The diversity of biological species results in the diversity of chemical structure and biological activity of isoflavonoids, such as antioxidant, anti-inflammatory, anticancer, anti-hyperkinesias. Structure modification, which can improve the solubility of the parent isoflavone, is an important way in exploring new drugs. In order to study the bromination, the crystal structure and the supramolecular forces of the isoflavonoids, 6 kinds of isoflavone bromides and 9 kinds of single crystals were synthesized and determined.First, the bromination reaction and the crystal structure of isoflavone bromides were studied. 6 kinds of isoflavone bromides were synthesized using daidzein, genistein and ipriflavone as leading compound and they are 6,8,3',5'-tetrabromo-7,4'-dihydroxy-isoflavone(1), 6,8,3',5'-trtrabromo-5,7,4'-trihydroxyisoflavone(2), 3, 6-di-bromo-2,7-dimethoxy-4'-hydroxyisoflavanone (3), 3,8-dibromo-2-methoxy-7-isopropoxyiso-flavanone(4), 3,6-dibromo-2-methoxy-7-isopropoxy-iso-flavanone(5), 8-bromo-7-iso-propoxyisoflavone (6), respectively. 1~5 are all new compounds, of which 1, 2 and 6 are isoflavone bromides, 3, 4 and 5 are isoavanone bromides. They were characterized by IR, 1H NMR and 13C NMR. The reaction of isoflavone is attributed to electrophilic addition and substitution mechanism. The bromination on the double bond C2=C3 was first reported. That whether the addition reaction can be proceeding on the double bondof rings C or not relies on the substitute of C7 and the media. If the substitute at C7 is alkyloxyl group, such as methoxyl group, isopropoxyl groups, the addition reaction can take place, if the substitute at C7 is hydroxyl group, the addition reaction cannot proceed. Single X-ray diffractometer was used to determine the structure of 4, 5 and 6. In the crystal structure of 4 and 5, the C—H##-7i and Br"'7i interactions are found along with hydrogen bonds and aromatic %-% stacking interactions. 6 crystallized in tetragon system which is rare found in the organic compound, the Tt-n stacking interactions, hydrogen bonds, and Br*-Br contacts assemble 6 into a high-symmetry helical supramolecular compound.Secondly, the crystal structure and supramolecular forces of the isoflavone sulfated are discussed. In the crystal structures of strontium 7-methoxy-4'-hydroxy-isoflavone -3'-sulfonate (8), nickel 7-methoxy-4'-hydroxy-isofiavone-3'-sulfonate (9) and zinc 7-methoxy-4'-hydroxyisoflavone-3'-sulfonate (10), the oxygen atoms, existence in sulfo groups, coordinated water molecules, latticed water molecules, hydroxyl groups, carbonyl groups and methoxyl groups, can acted as a hydrogen bond donor as well hydrogen bond acceptor, thus, many O—H*"O hydrogen bonds existed. The hydrogen bonds among sulfo-group, latticed water molecules, coordinated water molecules and hydroxyl groups, the %-% stacking interactions existence of the isoflavone skeletons and the electrostatic interactions between the cations and the anions lead the isoflavone sulfonate into supramolecules with three-dimensional structures. A hydrophilic region is formed among sulfo-group, latticed water molecules and coordinated water molecules via hydrogen bonds, a hydrophobic region are formed through the n-n. stacking interactions of the isoflavone skeletons. The sulfo group is a vital bridge in structural link between the hydrophilic region and hydrophobic region, as well inorganic and organic components.Last, the crystal structure and supramolecular forces of the methlated isoflavone are studied. The C —H---0 hydrogen bond assemble 7,4'-dimethoxyl- isoflavone(ll) and 7,4'-di-methoxyl-5-hydroxylisoflavone into a three dimensional network together with aromatic 7i-7i stacking interactions. While only C—H**-0 hydrogen bond was found in 7,4'-diethoxyl-O-isoflavone(l 3).Two kinds of reaction were found when isoflavone reaction with bromine and they are electrophilic addition and substitution reaction. The position and the H atoms, which will be substituted, are decided by the orientation group. Few studies on the reaction of...