Polysulfonylamine, CXIX Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Ein antidromes Achtringmuster als robustes supramolekulares Synthon - Drei prototypische Strukturen/Polysulfonylamines, CXIX Hydrogen Bonding in Crystalline Onium Dimesylamides: An Antidromic Eight-Membered Ring Pattern as a Robust Supramolecular Synthon - Three Prototypical Structures

Abstract

Syntheses and low-temperature X-ray structures are reported for three ionic solids of general formula BH+(MeSO2)2N-, where BH+ is 3,4,6,7,8,9-hexahydro-2H-pyrimido[1,2-a]pyrimidinium (1, monoclinic, space group P21/c), N,N′-diphenylformamidinium (2, monoclinic, P21/c), or 2-phenylaminopyridinium (3, triclinic, P1̄̄, two independent formula units). As a common feature, the onium cations in question exhibit a difunctional hydrogen-bond donor sequence H -N -C (sp2) - N - H geometrically complementary to an O - S - N fragment of the anion. Consequently, the three crystal packings consist of discrete cation-anion pairs (formula units) assembled by an N -H ··· N and an N - H O hydrogen bond. In both independent ion pairs of 3, the N -H ··· N bond originates from the pyridinium centre and the N - H - O bond from the amino group. The eight-membered ring [graph set N2 = R22(8), antidromic] that results in all these prototypical structures has potential as a new and robust supramolecular synthon. In each case, short C - H ··· O contacts with H ··· O ≤ 260 pm and C - H ··· O ≥ 140° are present; in 2, two Car - H ··· O hydrogen bonds are assisted by a C(formyl)- H ··· O contact and a π - π interaction to create a centrosymmetric formula unit dimer.

Polysulfonylamines. CXXXII.

“…In order to demonstrate its high probability of formation, the motif in question was successfully integrated into hydrogenbonded assemblies of increasing complexity, i.e. prototypical ion pairs (Wijaya et al, 1999), cyclodimers and catemers of ion pairs (Moers, Wijaya et al, 2000), and three-dimensional networks (Wijaya et al, 2000). The 2-aminopyridinium salt (I) represents an example for a catemeric structure composed of R 2 2 (8) bonded ion pairs, and the structure determination of the analogous title compound, (II), was carried out in order to evaluate the in¯uence of a sterically more demanding disulfonylamidate anion on the robustness of the target motif.…”