π-Stacked dimers in 6-methoxy-3,3-dimethyl-3<i>H</i>-benzo[<i>f</i>]chromene, and centrosymmetric dimers containing C—H...π(arene) hydrogen bonds in racemic 3-bromo-2,2,6,6-tetramethyl-3,4-dihydro-2<i>H</i>,6<i>H</i>-1,5-dioxatriphenylene
作者:Fernando de C. da Silva、James L. Wardell、Solange M. S. V. Wardell、Vitor F. Ferreira、John N. Low、Christopher Glidewell
DOI:10.1107/s0108270107039194
日期:2007.10.15
The title compounds, namely 6- methoxy- 3,3- dimethyl- 3Hbenzo[ f] chromene, C16H16O2, ( III), and racemic 3- bromo2,2,6,6- tetramethyl- 3,4- dihydro- 2H, 6H- 1,5- dioxatriphenylene, C20H21BrO2, ( IV), were both synthesized in one- step regioselective Wittig reactions from substituted 1,2- naphthoquinones. The new ring in both compounds adopts a screw- boat conformation. A single pi-pi stacking interaction links the molecules of ( III) into centrosymmetric dimeric aggregates, and a single C - H center dot center dot center dot pi( arene) hydrogen bond links the molecules of ( IV) into centrosymmetric dimers.