organic compounds
Molecules of the title compound [systematic name: 2,4,6-(pentafluorophenyl)-1,3,5,2,4,6-trioxatriborinane], C18B3F15O3, are located on crystallographic twofold rotation axes which run through the boroxine and one of the pentafluorophenyl rings. The boroxine ring (r.m.s. deviation = 0.027 Å) and the pentafluorophenyl rings (r.m.s. deviations = 0.004 and 0.001 Å) are essentially planar. The dihedral angles between the boroxine and the two symmetry-independent benzene rings are 8.64 (10) and 8.74 (12)°. The two benzene rings are mutually coparallel [dihedral angle = 0.80 (11)°]. The packing shows planes of molecules parallel to (01), with an interplanar spacing of 2.99 Å. Within these planes, all the molecules are oriented in the same direction, whereas in neighbouring planes the direction is inverted. Short BF contacts of 3.040 (2) and 3.1624 (12) Å occur between planes. The geometric parameters of the boroxine ring in the title compound agree well with those of comparable boroxine structures, while the packing reveals some striking similarities and differences.
organic compounds
The crystal structures of five dibromobenzene derivatives, namely dibromoborylbenzene, C6H5BBr2, (I), 1-dibromoboryl-4-(trimethylsilyl)benzene, C9H13BBr2Si, (II), 4-bromo-1-(dibromoboryl)benzene, C6H4BBr3, (III), dibromo(dimethylamino)(phenyl)borane, C8H12BBr2N, (IV), and dibromo(dimethylsulfanyl)[4-(trimethylsilyl)phenyl]borane, C11H19BBr2SSi, (V), have been determined. Compounds (I)-(IV) crystallize with one molecule in the asymmetric unit, but the molecule of (V) is located on a crystallographic mirror plane, implying twofold disorder of the central aromatic ring, the S atom and one of the methyl groups bonded to the S atom. In (I), (II) and (III), the B atom is three-coordinated, and in (IV) and (V) it is four-coordinated. The geometric parameters of the -BBr2 group in these five structures agree well with those of comparable structures retrieved from the Cambridge Structural Database. The C-B and B-Br bond lengths in the molecules with a three-coordinated B atom are significantly shorter than those in the molecules with a four-coordinated B atom. In the compounds with a three-coordinated B atom, the -BBr2 group tends to be coplanar with the aromatic ring to which it is attached.