POLYSULFONYLAMINES .58. CONSERVATION OF T HE 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 2 MODIFICATIONS OF FREE DIMESYLAMINE/

The title compound 1 is an unprecedented example of an 18-crown-6 comp lex in which coronand rings preserve the conformation of the uncomplex ed crystalline polyether. 1 is precipitated, independently of the mola r ratio employed, by mixing methanolic solutions of its components at room temperature. The complex crystallizes in the monoclinic system, s pace group P2(1)/n, with (at -130 degrees C) a = 1771.9(7), b = 833.3( 3), c = 2024.2(6) pm, beta = 107.13(3)degrees, V = 2.856(2) nm(3), Z = D-x = 1.325 Mg m(-3). The structure contains infinite chains of alter nating host and guest species, in which every HN(SO2CH3)2 guest is lin ked via C-H... O(crown) and C-H... O(sulfonyl) interactions with two D -3d-pseudosymmetric crown rings. Within the chain, each D-3d ring acts as an acceptor in six C-H O(crown) and as a donor in four C-H... O(su lfonyl) interactions. Equivalent molecules in the chain are related by y-translation. Pairs of antiparallel chains are connected into ladder -like strands by a second type of 18-crown-6 molecule that crystallogr aphically preserves the centrosymmetric C'(i) conformation of the unco mplexed polyether. These rings accept, via their two symmetry-related pseudocorner oxygen atoms, an N-H... O hydrogen bond (H... O 210 pm) f rom one guest molecule in each chain and are also connected to the sam e guests by a C-H...O(sulfonyl) interaction. Parallel strands are link ed through C-H(crown)... O(sulfonyl) and C-H(crown)... O(crown) intera ctions to form a three-dimensional network. The H... O distances of th e strand-building and the strand-connecting C-H...O interactions lie i n the range 230-260 pm. For comparison, two modifications of the pure guest compound, crystallized from CCl4 (modification 2a) or CH2Cl2 (mo dification 2b), were structurally characterized. The crystallographic data (at -95 OC) are for 2 a: monoclinic, space group P2(1)/c, a = 767 .5(2) b = 974.5(2), c = 915.0(3) pm, beta = 105.80(2)degrees, V = 0.65 85(3) nm(3) Z = 4, D-x = 1.747 Mg m(-3), for 2b: monoclinic, space gro up P2(1)/c, a = 776.2(3), b = 997.1(3), 923.0(4) pm, beta = 111.10(3)d egrees, V = 0.6665(4) nm(3) Z = 4, D-x = 1.726 Mg m(-3). In both modif ications, 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 pr incipal difference between 2a and 2b arising from the differing confor mational character of the acceptor oxygen atoms. Corresponding bond le ngths 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 C-1 symmetry of the CO2SNSO2C framework in 2a and 2b changes to an approximate C-2 symmetry upon complexation with 1 8-crown-6, thus optimizing the host-guest complementarity.