Polysulfonylamine, CLXIX. Intermolekulare Wechselwirkungen in kristallinen Di(organosulfonyl)aminen. Teil 1. Di(4-brombenzolsulfonyl)amin: Zwei Konformationspolymorphe und Strukturverwandtschaft eines Polymorphs mit dem entsprechenden 2,4-Dimethylpyridinium-Salz / Polysulfonylamines, CLXIX. Intermolecular Interactions in Crystalline Di(organosulfonyl)- amines. Part 1. Di(4-bromobenzenesulfonyl)amine: Two Conformational Polymorphs and the Structural Relationship of one Polymorph to the Corresponding 2,4-Dimethylpyridinium Salt

Abstract

Two crystal structures (polymorphs) of di(4-bromobenzenesulfonyl)amine (1), as determined by low-temperature single-crystal X-ray diffraction, are reported: Form A, monoclinic, P21/c, Z' = 1; form B: monoclinic, P21/c, Z' = 2. In A, the molecule adopts an extended conformation approximating to C2 symmetry, whereas the two independent molecules of form B display a folded hair-pin conformation with pseudo-mirror symmetry [torsion τ (C-S···S’-C’) and intercentroid distance dIC of the aromatic rings in A: 173.2° and 750.8 pm, in B: −5.4/−8.90° and 364.1/366.5 pm]. The packings of both polymorphs consist of layers, in which the molecules are connected by N-H···O hydrogen bonds in one and by Br···O interactions in the other dimension. The 1:1 onium salt (2; monoclinic, P21/n, Z' = 1) produced on N-deprotonation of 1 with 2,4-dimethylpyridine is structurally related to B. Its packing involves strands of formula units, whereby the anions retain the folded conformation (τ = 5.8°, dIC = 372.5 pm) and perfectly mimic the catemeric Br···O pattern of B, while the cations are isotactically connected to the anion backbone via an N-H(···O)2 three-centre bond. In all structures, a three-dimensional network of weak hydrogen bonds C-H···A (A = O, in 2 also N−) and C-H···Br contacts supports the controlling N-H···O and Br···O interactions; moreover, an intermolecular (π···π) stacking dimer of the type phenyl/phenyl and a (π···π) stacking trimer of the type phenyl/pyridinium/phenyl have been identified in A and 2, respectively. None of the structures exhibits very short bromine-bromine contacts suggestive of specific attractive forces.