Polysulfonylamines .96. Homoconjugates formed from di(organosulfonyl)amines and their conjugate anions: Four crystal structures featuring asymmetric [N-H center dot center dot center dot N](-) hydrogen bonds

The following compounds were prepared by cocrystallization of their components from MeOH or MeCN and structurally characterized by low-temperature X-ray diffraction: Na[N(SO2Me)(2)]. HN(SO2Me)(2) . 2 (12-crown-4) (2, orthorhombic, space group Pna2(1)), Na[N(SO2Me)(2)]. HN(SO2Me)(2) .(15-crown-5) (3, monoclinic, P2(1)/n), Na[N(SO2Ph)(2)]. HN(SO2Ph)(2) . 2 (12-crown-4) (4, monoclinic, P2(1)), (MeNH)(2)CO . HN(SO2Ph)(2) . 0.5 MeCN (5, monoclinic, P2(1)/n). The four structures exhibit [(RSO2)(2)N-H ... N(SO2R)(2)](-) anions as rare examples of intermolecular [N-H ... N](-) homoconjugates. The N ... N distances of the asymmetric hydrogen bonds are, in order, 266.9(6), 276.0(3), 291.3(4) and 279.4(2) pm, the corresponding N-H ... N angles amounting to 137(10), 176(3), 177(4) and 177(2)degrees. The asymmetry of the hydrogen bonds is clearly reflected in the geometry of the NS2 groups (amine moieties: N-S 162.3-165.2 pm, S-N-S 124.5-127.1 degrees; amide moieties: N-S 159.7-161.8 pm, S-N-S 119.1-122.6 degrees). The dihedral angles formed by the NS, planes vary from 51.8 degrees in 4 to 87.6 degrees in 5. The crystal lattices of 2 and 4 consist of discrete ions, sandwich-type [Na(12-crown-4)(2)](+) complexes acting as the counter-ions. In 3, Na+ is coordinated in an out-of-cavity pattern by the five polyether oxygen atoms and further accepts two Na-O bonds from the amide moiety of the complex anion [Na-O(crown) 241.5(2)-249.9(2), Na-O(anion) 235.0(2) and 263.9(2) pm]. The surprising structure of 5 contains homoconjugated 1,3-dimethylurea cations [(MeNH)(2)C-O-H ... O=C(NHMe)(2)](+), which are formed via a very strong asymmetric [O-H ... O](+) hydrogen bond [O ... O 247.7(2) pm, O-H ... O 172(3)degrees] and are associated with the amide moieties of the anions through a set of N-H ... O bonds to form infinite chains; the MeCN molecules occupy lattice cavities.