Crucial influence of solvent and chirality-the formation of helices and three-dimensional nets by hydrogen-bonded biimidazolate complexes.
Deprotonation and recrystallisation of racemic [Co(2,2'-biimidazole)3][NO3]3 by ammonia in water/dimethylformamide solutions gave crystals of [Co(Hbiim)3] x 0.8H2O x 0.5DMF (2: Hbiim = monoanion of 2,2'-biimidazole, DMF = dimethylformamide), a porous material that contains fourfold interpenetrating (10.3) three-dimensional nets formed by neutral, hydrogen-bonded [Co(Hbiim)3] units, with DMF molecules in the narrow channels. Recrystallisation of [delta-Co(2,2'-biimidazolate)3] gave helices instead of the expected (10,3)-a net. These results are discussed in the light of additional density functional theory and molecular mechanics calculations and the X-ray structure of [Co(H2biim)3][NO3]3.
Ohrström
L
L
Department of Inorganic Chemistry, Chalmers Tekniska Högskola, Gothenburg, Sweden. ohrstrom@inoc.chalmers.se
Larsson
K
K
Borg
S
S
Norberg
S T
ST