The Synthesis And Crystal Structure Study On3,9-Disubstituted-2,4,8,10-tetra-Oxaspiro[5.5]Undecane

In this dissertation,3,9-disubstituted-2,4,8,10-tetraoxaspiro[5.5]undecanic compounds were synthesized with halogeneated benzaldehyde and pentaerythritol as material by phosphotungstic acid as catalyst.The chemical environment of the methylenes existing in six members heterocycles were analyzed and assigned by1HNMR.We analyzed that halogen substituent in the terminal aromatic rings influenced the chemical shifts of methylenes existing in six members heterocycles.When it was the ortho-substituted group which was closer to the six members heterocycle comparing with the para-substituted group, the chemical shifts of methylenes shifted toward downfield and the values increased as a result of the vander waals effect. When the polarity of halogen substituent increased,the electron density of the protons in the six members heterocycles was reduced owing to the inducting effects,and the chemical shifts of methylenes were in higher field.Single crystals of3,9-bis(4-fluorophenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane,3,9-bis(2-chlorophenyl)-2,4,8,10-tetraoxaspiro[5.5]undecane and3,9-bis(2-bromophenyl)-2,4,8,10-tetraoxaspiro-[5.5]undecane were cultured by solution crystallization and confirmed by X-ray single crystal diffraction instrument.The three single crystals were all monoclinic,belong in the racemate and included R,S configuration, but their crystals structure was different.R, S configuration in crystal cell of3,9-bis(4-fluorophenyl)-2,4,8,10-tetraoxaspiro-[5.5]undecan respectively have two state.S configuration layer was composed of three layers like "Sb-Sa-Sb". Sa configuration molecules formed a two-dimensional network structure along the "ab" plane by the electronic weak interaction of C-H...F bonds. Sb configuration molecules anchored Sa configuration molecular layer along "c" axis through the overlapping effects of the π-π bonds and the weak interaction of C-H...π and C-H...O bonds. Molecular interaction of the R configuration layers was the same as that of S configuration layers. Through weak interaction of the C-H... F bonds and overlapping effects of π-π bonds, S configuration layers interlaced with R configuration layers to form a three-dimensional network structure.R, S configuration molecules of3,9-bis(2-chlorophenyl)-2,4,8,10-tetraoxaspiro[5.5]-undecane crystals respectively, side by side along "a" axis,formed a one-dimensional chain structure,then constituted a two-dimensional network structure by the weak interaction of C-H...π bonds and overlapping effects of π-π bonds.The compound crystal can’t form three dimensional structure because of only two molecular layers of R configurations and S configuration along the direction of "c" axis.R configuration molecules of3,9-bis(2-bromophenyl)-2,4,8,10-tetraoxaspiro[5.5]-undecane formed a one-dimensional molecular chain through the overlapping effects of π-π bonds.S configuration molecules also did.Through the weak interaction of C-H...O and C-H...π bonds,two molecular chains interlaced and formed two-dimensional network structure along "a" axis.The crystal forms three molecular layers along the direction of "c" axis by the overlapping effects of π-π bonds.