Synthesis, π‐Face‐Selective Aggregation, and π‐Face Chiral Recognition of Configurationally Stable C3‐Symmetric Propeller‐Chiral Molecules with a π‐Core. Issue 19 (15th April 2014)

• Record Type: Journal Article
• Authors: Saito, Nozomi; Terakawa, Ryo; Yamaguchi, Masahiko
• Is Part Of: Chemistry. Volume 20:Issue 19(2014)
• Page Start: 5601
• Page End: 5607
• Publication Date: 2014-04-15
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201400094
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The <italic>C</italic><sub>3</sub>‐symmetric propeller‐chiral compounds (<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold> and (<italic>M</italic>, <italic>M</italic>, <italic>M</italic>)‐<bold>1</bold> with planar π‐cores perpendicular to the <italic>C</italic><sub>3</sub>‐axis were synthesized in optically pure states. (<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold> possesses two distinguishable propeller‐chiral π‐faces with rims of different heights named the (<italic>P</italic>/<italic>L</italic>)‐face and (<italic>P</italic>/<italic>H</italic>)‐face. Each face is configurationally stable because of the rigid structure of the helicenes contained in the π‐core. (<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold> formed dimeric aggregates in organic solutions as indicated by the results of <sup>1</sup>H NMR, CD, and UV/Vis spectroscopy and vapor pressure osmometry analyses. The (<italic>P</italic>/<italic>L</italic>)/(<italic>P</italic>/<italic>L</italic>) interactions were observed in the solid state by single‐crystal X‐ray analysis, and they were also predominant over the (<italic>P</italic>/<italic>H</italic>)/(<italic>P</italic>/<italic>H</italic>) and (<italic>P</italic>/<italic>L</italic>)/(<italic>P</italic>/<italic>H</italic>) interactions in solution, as indicated by the results of <sup>1</sup>H and 2D NMR spectroscopy analyses. The dimerization constant was obtained for a racemic mixture, which showed that the heterochiral (<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold>/(<italic>M</italic>, <italic>M</italic>, <italic>M</italic>)‐<bold>1</bold> interactions were much weaker than the homochiral (<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold>/(<italic>P</italic>, <italic>P</italic>, <italic>P</italic>)‐<bold>1</bold> interactions. The results indicated that the propeller‐chiral (<italic>P</italic>/<italic>L</italic>)‐face interacts with the (<italic>P</italic>/<italic>L</italic>)‐face more strongly than with the (<italic>P</italic>/<italic>H</italic>)‐face, (<italic>M</italic>/<italic>L</italic>)‐face, and (<italic>M</italic>/<italic>H</italic>)‐face. The study showed the π‐face‐selective aggregation and π‐face chiral recognition of the configurationally stable propeller‐chiral molecules.</p> </abstract>