The wide range of pharmacological activities (e.g. antiviral, antifungal, antibacterical,
antiinflamatory, leishmanicidal and antidepresant) has already been attributed to the
xanthenediones, a group of synthetic heterocyclic compounds possessing a pyran
nucleus fused on either side with cyclohex-2-enone rings [1]. In this work, two 3,3,6,6-
tetramethyl-9-substituted-3,4,5,6,7,9-hexahydro-1H-xanthene-1,8(2H)-diones (Figure
1) were synthesized and their crystal stuctures were determined by single crystal X-ray
diffraction. The main structural feature in compound 1 is a supramolecular chain along
the a-axis formed by O4–H4···O2 hydrogen bond and C13–H13···O4 and Br1···Br2
interactions between the adjacent asymmetric units, while the formation of
supramolecular network is further achieved by C–H···π interactions between the
adjacent chains. The main motif in 2 is a dimer formed via O4–H4···O2 hydrogen bond
and Cl1···π interactions. The neighbouring dimers are connected through strong C7–
H7A···π interactions, thus resulting in formation of a zigzag chain parallel to the c-axis.
Weak C–H···π interactions link the adjacent chains into a supramolecular layer. This
work may provide a basis for design of new biologically active xanthenediones both at
the molecular and supramolecular level