Crystal and molecular structure of bis-(2,2'-biphenylene)-methane

Crystals of bis-(2,2'-biphenylene)methane are monoclinic of space group P2t/c with cell constants a = 10.173, b= 10.241, c=16.722 A, fl=96.54 °, Z = 4 . The molecular symmetry is 1 as a result of the deviations from planarity of both biphenyl groups. The four central C-C-bonds are 1.53/~,, which is appreciably larger than the corresponding bond lengths in fluorene. The sp2-sp 2 single bonds in the biphenylene groups are 0.03/~ smaller than the corresponding bond in biphenyl itself.