Inter-ring and endo anomeric effects, and hydrogen-bonded supramolecular motifs in two 2,4,6,8-tetraazabicyclo[3.3.0]octane derivatives.
In 2,4,6,8-tetrakis(4-chlorophenyl)-2,4,6,8-tetraazabicyclo[3.3.0]octane, C(28)H(22)Cl(4)N(4), the imidazolidine rings adopt envelope conformations, which are favoured by two equal endo anomeric effects. The molecule lies on a crystallographic twofold axis and molecules are linked into a three-dimensional framework via two C-H...Cl hydrogen bonds. In 2,4,6,8-tetrakis(4-methoxyphenyl)-2,4,6,8-tetraazabicyclo[3.3.0]octane, C(32)H(34)N(4)O(4), one of the methyl groups is disordered over two sets of sites and the same methyl group participates in an intermolecular C-H...O hydrogen bond, which in turn causes a considerable deviation from the preferred conformation. There are two unequal inter-ring anomeric effects in the N-C-N groups. Molecules are linked into corrugated sheets by one C-H...pi hydrogen bond and two independent C-H...O hydrogen bonds involving methoxy groups.
College of Chemistry and Environmental Science, Henan Normal University, Xinxiang 453007, People's Republic of China. zzf5188@sohu.com
Zhenfeng
Z
Zhang
Jiange
J
Wang
Guisheng
G
Zhang
Jianpin
J
Li