Ja. Yang et al., THE POTASSIUM-SALT OF 9-(2,4,6-TRINITROANILINO)CARBAZOLE, Acta crystallographica. Section C, Crystal structure communications, 50, 1994, pp. 1548-1550
The picryl ring in the potassium salt of 9-(2,4,6-trinitroanilino)carb
azole [potassium N-(9-carbazolyl)-2,4,6-trinitroanlidide, K+.C18H10N5O
6-] is in a boat conformation. The C-N bond between C1 of the picryl r
ing and the adjacent N atom of the hydrazine moiety is shortened, indi
cating delocalization of the -1 charge into the picryl ring system. Th
e K+ ion, which has replaced the proton on the N atom bonded to C1, is
ionically bonded to this N atom and to an O atom in an ortho nitro gr
oup of the parent molecule. K+ also coordinates with four O atoms from
three other molecules and with the pi cloud of a phenyl ring of the c
arbazole group of a fourth molecule.