1 | Author | Jones | Requires cookie* |

Title | Polysulfonylamine | ||

Abstract | , LIV [1] (12-Krone-4)lithiumdimesylamid-Acetonitril (3/2): Ein Kristall mit zwei prinzipiell unterschiedlichen Konformationen des gleichen Coronanden Polysulfonylam ines, L IV [1] (12-Crow n-4)lithium D im esylam ide-A cetonitrile (3/2): A Crystal w ith Two F undam entally D ifferent C onform ations of the Sam e C oronand A rm an d Blaschette*, K arl-H einz N agel, P e te r G. [Li(12-crown-4){N(S02CH3)2}] is obtained from equimolar amounts of lithium dimesyl amide and 12-crown-4 in methanol and crystallizes from acetonitrile as a 3/2 solvate. The crystallographic data of the latter at -130 °C are: monoclinic, space group P 2In, a = 1053.4(3), b = 904.3(3), c = 2791.2(8) pm, ß = 95.66(3)°, V = 2.646 nm3, Z = 6, Dx = 1.441 Mgm~3. Apart from CH3CN molecules residing in lattice cavities, the structure consists of two crystallogra-phically independent [Li(12-crown-4){N(S02CH3)2}] ion pairs A and B in the ratio 2:1. In B, the Li and N atoms lie on a crystallographic twofold axis. In both ion pairs, Li is hexa-coordinated by the four crown oxygen atoms O(C) and by one oxygen O(S) from each sul-fonyl group of the anionic ligand. The coordination geometry of Li in A closely resembles that of Cu11 in the known structure of [Cu(12-crown-4)Cl2] and can be pictured as a distorted octahedron, where two cis sites are occupied by the O(S) atoms and the remaining vertices by the four oxygens of the macrocycle, which displays a [4 8] conformation. The lithium atom, the two O(S) and two O(C) atoms are arranged in an approximately square-planar pattern with L i-O (S) 203.6 and 205.1, L i-O (C) 206.9 and 219.1 pm, trans angles of 173.7 and 174.8°, and cis angles in the range 87.1 -93.6°. The angle between the remaining two Li -O(C) bonds with distances 214.7 and 221.5 pm is only 146.5° compared with 180° in an ideal octahedron. In ion pair B, the coronand assumes a [3 3 3 3] conformation close to C4 symmetry, as observ ed e. g. in the known structures of [Li(12-crown-4)NCS] with a square-pyramidal 0 4N-co-ordination and [Ca(12-crown-4)(H20) 4]Cl2-4 H zO with a square-antiprismatic 0 8-geometry. The coordination polyhedron in B can be viewed as an incomplete cube in which two verti ces related by a face diagonal are unoccupied. Important bond lengths and angles in B are: L i-O (S) 216.8, L i-O (C) 214.0 and 228.7pm; 0 (S) -L i-0 (S) 82.0, 0 (C) -L i-0 (C) 75.7/76.3 for adjacent and 120.4/121.9° for opposite ring oxygens. | ||

Reference | (Z. Naturforsch. 49b, 36—42 [1994]; eingegangen am 2. September 1993) | ||

Published | 1994 | ||

Keywords | Polysulfonylamines, (12-Crown-4)lithium Dimesylamide, Synthesis, Crystal Structure, Coronand Conformation | ||

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