Conformational diversity: Six conformers side-by-side in the crystal cell of 2,2′,7,7′-tetramethoxy-9,9′-spiro-9-silabifluorene
作者:I. L. Karle、R. Butcher、M. A. Wolak、S. H. Lee、Z. H. Kafafi
DOI:10.1007/s10870-006-9129-x
日期:2007.2.14
X-ray crystal structure analysis of a sublimation-grown spiro silabifluorene, that is highly fluorescent in the violet-blue, established that there are six cocrystallized ordered conformers in the asymmetric unit. Crystals were grown by a vapor transport method under argon gas flow at temperatures between 255–280°C. As expected, there are no cocrystallized solvent molecules. There is no π-stacking of the aryl groups. There is no possibility for normal hydrogen bond formation; however, several CH⋯π bonds occur. The packing is efficient with a density of 1.24 g/cc. Each conformer deviates from tetrahedral geometry around the Si atom. Cell data are: C28H24O4Si×12, sp. gr. P $\bar 1$ , a=16.2750(5) Å, b=20.6613(5) Å, c=23.8289(5) Å, α=102.025(2)°, β=94.252(2)°, and γ=109.916(2)°, V=7275(1) Å3.
升华生长螺状硅基芴(在紫蓝色下具有高荧光性)的X射线晶体结构分析证实,不对称单元中有六个共结晶有序构象。晶体是在氩气流下,在255-280°C的温度范围内通过蒸汽传输法生长的。正如预期的那样,没有共结晶溶剂分子。芳基没有π-堆积。不可能形成正常的氢键;然而,出现了几个CH⋯π键。堆积密度为1.24 g/cc,非常有效。每个构象偏离了Si原子周围的四面体几何结构。晶胞数据为:C28H24O4Si×12,比重P $\bar 1$ ,a=16.2750(5) Å,b=20.6613(5) Å,c=23.8289(5) Å,α=102.025(2)°,β=94.252(2)°,γ=109.916(2)°,V=7275(1) Å3。