The crystal and molecular structure of the complex, cryptolepine-tetrapheny
lborate, C16H13 N-2(+).(C6H5)(4)B-, has been determined by direct methods.
The pale yellow crystals are monoclinic, P2(1)/n, a = 11.039(5), b = 16.491
8(7), c = 16.404(2) Angstrom, beta = 95.70(1)degrees, V = 2968.75 Angstrom(
3), and Z = 4. The structure exhibits an unusual form of static disorder wi
th the planar cryptolepine molecules occupying a cleft between tetraphenyl
berate molecules. The disorder involves essentially planar cryptolepine mol
ecules packed in one of two orientations in the cleft, related by an almost
exact noncrystallographic twofold rotation axis passing through the molecu
les. The tetraphenyl berate cation, on the other hand, shows no disorder. T
he distribution of bonds around the boron atom is essentially tetrahedral a
nd the four phenyl rings are planar within experimental error.