Crystal structures and Hirshfeld surface analyses of 6,8-dimethoxy-3-methyl-1 H -isochromen-1-one and 5-bromo-6,8-dimethoxy-3-methyl-1 H -isochromen-1-one chloroform monosolvate

• Published in: Acta crystallographica. Section E, Crystallographic communications Crystallographic communications, 2020-07, Vol.76 (7), p.1107-1112
• Main Authors: Tiouabi, Mustapha, Tabacchi, Raphaël, Stoeckli-Evans, Helen
• Format: Article
• Language: English
• ISSN: 2056-9890; 2056-9890
• DOI: 10.1107/S2056989020007975

In the molecule of 6,8-dimethoxy-3-methyl-1 H -isochromen-1-one, C 12 H 12 O 4 , ( I ), the two methoxy groups are directed anti with respect to each other. In the molecule of the brominated derivative, 5-bromo-6,8-dimethoxy-3-methyl-1 H -isochromen-1-one, that crystallized as a chloroform monosolvate, C 12 H 11 BrO 4 ·CHCl 3 , ( II·CHCl 3 ), the methoxy groups are directed syn to each other. In the crystal of I , molecules are linked by bifurcated C—H...O hydrogen bonds, forming chains along the c -axis direction. The chains are linked by C—H...π interactions, forming a supramolecular framework. In the crystal of II·CHCl 3 , molecules are linked by C—H...O hydrogen bonds forming 2 1 helices parallel to the b -axis direction. The chloroform solvate molecules are linked to the helices by C—H...O(carbonyl) hydrogen bonds. The helices stack up the c -axis direction and are linked by offset π–π interactions [intercentroid distance = 3.517 (3) Å], forming layers parallel to the (100) plane. Compound II·CHCl 3 was refined as a two-component twin. Two chlorine atoms of the chloroform solvate are disordered over two positions and were refined with a fixed occupancy ratio of 0.5:0.5.