Polysulfonylamine, LVIII [1] Erhaltung der Konformation des unkomplexierten Koronanden in einem supramolekularen 18-Krone-6-Komplex: Darstellung und Kristallstrukturen von 18-Krone-6-Dimesylamin (3/2) und von zwei Modifikationen des freien Dimesylamins / Polysulfonylamines, LVIII [1] Conservation of the Conformation of the Uncomplexed Coronand in a Supramolecular 18-Crown-6 Complex: Formation and Crystal Structures of 18-Crown-6-Dimesylamine (3/2) and of Two Modifications of Free Dimesylamine

Abstract

The title compound 1 is an unprecedented example of an 18-crown-6 complex in which coronand rings preserve the conformation of the uncomplexed crystalline polyether. 1 is precipitated, independently of the molar ratio employed, by mixing methanolic solutions of its components at room temperature. The complex crystallizes in the monoclinic system, space group P21/n, with (at -130°C) a = 1771.9(7). b = 833.3(3), c = 2024.2(6) pm, β = 107.13(3)°, V = 2.856(2) nm3, Z = 4. Dϰ = 1.325 Mg m-3. The structure contains infinite chains of alternating host and guest species, in which every HN(SO2CH3)2 guest is linked via C-H ··· O(crown) and C-H ··· O(sulfonyl) interactions with two D3d-pseudosymmetric crown rings. Within the chain, each D3d ring acts as an acceptor in six C-H ··· O(crown) and as a donor in four C-H -O(sulfonyl) interactions. Equivalent molecules in the chain are related by v-translation. Pairs of antiparallel chains are connected into ladder-like strands by a sec­ond type of 18-crown-6 molecule that crystallographically preserves the centrosymmetric C′i conformation of the uncomplexed polyether. These rings accept, via their two symmetry- related pseudocorner oxygen atoms, an N-H ··· O hydrogen bond (H ··· O 210 pm) from one guest molecule in each chain and are also connected to the same guests by a C-H ··· O(sulfonyl) interaction. Parallel strands are linked through C-H- (crown) ··· O(sulfonyl) and C-H(crown) ··· O(crown) interactions to form a three-dimensional network. The H ··· O distances of the strand-building and the strand-connecting C-H ··· O interactions lie in the range 230-260 pm. For comparison, two modifications of the pure guest compound, crystallized from CCl4 (modification 2a) or CH2Cl2 (modification 2b), were structurally characterized. The crystallographic data (at -95 °C) are for 2a: monoclinic, space group P21/c, a = 767.5(2), b = 974.5(2), c = 915.0(3) pm, β = 105.80(2)°, V = 0.6585(3) nm3, Z = 4, Dϰ = 1.747 Mg m-3; for 2b: monoclinic, space group P21/c, a = 776.2(3), b = 997.1(3), c = 923.0(4) pm, β = 111.10(3)°, V = 0.6665(4) nm3. Z = 4, Dϰ = 1.726 Mg m 3. In both modifications, the molecules are connected by an N-H ··· O hydrogen bond (H ··· O 234 pm in 2a, 220 pm in 2b) into chains in the z-direction, the principal difference between 2a and 2b arising from the differing conformational character of the acceptor oxygen atoms. Corresponding bond lengths and bond angles in 2a and 2b and in the guest molecule of 1 are essentially identical, as are the torsion angles around the S-N bonds in 2a and 2b. The local C1 symmetry of the CO2SNSO2C framework in 2a and 2b changes to an approximate C2 symmetry upon complexation with 18-crown-6. thus optimizing the host-guest comple­mentarity.