Absolute configuration determination of theanti-head-to-head photocyclodimer of anthracene-2-carboxylic acid through cocrystallization withL-prolinol

Abstract

The absolute configuration has been established of the enantiopureanti-head-to-head cyclodimer of anthracene-2-carboxylic acid (AC) cocrystallized with L-propinol and dichloromethane [systematic name: (S)-2-(hydroxymethyl)pyrrolidin-1-ium (5R,6S,11R,12S)-8-carboxy-5,6,11,12-tetrahydro-5,12:6,11-bis([1,2]benzeno)dibenzo[a,e][8]annulene-2-carboxylate dichloromethane monosolvate], C5H12NO+·C30H19O4−·CH2Cl2. In the crystal structure, the AC dimer interacts with L-prolinol through a nine-membered hydrogen-bonded ring [R22(9)], while the dichloromethane molecule is incorporated to fill the void space. The absolute configuration determined in this study verifies a recent assignment made by comparing theoreticalversusexperimental circular dichroism spectra.