organic compounds
The title compound, C10H11BrO4, a useful precursor to pharmaceutically active isocoumarin and isochroman derivatives, crystallizes with two unique molecules in the asymmetric unit. A - stacking interaction links the planar molecules in the asymmetric unit. Additional - contacts stack pairs of molecules along the c axis. A feature of the crystal packing is the presence of a number of short BrO contacts. A particularly unusual arrangement involves the formation of dimers, with pairs of BrO contacts imposing a close BrBr interaction and generating five-membered rings within an eight-membered ring formed by two BrO contacts. Only two comparable arrangements have been reported previously. The BrO contacts combine with weak C-HO hydrogen bonds to form corrugated sheets of molecules approximately parallel to (001). These sheets are stacked along the c axis by - interactions to generate a three-dimensional network.