STRUCTURE OF A CYCLOPHANE HOST MOLECULE

The cyclophane tetramethyl -15,18,21:-33,36,39-diethenylylidenedibenzo [k,a1][ raoxacyclodotriacontene-1,2,19,20-tetracarboxylate acetonitril e solvate, C56H44012.CH3=N, contains a large cavity and forms host-gue st complexes in solution with a variety of quaternary nitrogen compoun ds. Crystallization from an acetonitrile solution that contained adama ntyltrimethylammonium iodide led, though, to crystals of the uncomplex ed cyclophane (but containing one molecule of acetonitrile of crystall ization). The cavity, about 7.6 x 4.0 angstrom and roughly rectangular in cross section, is occupied by ester groupings from two adjacent cy clophanes, entering from opposite sides. Crystal data: orthorhombic, . P2(1)2(1)2(1), with a = 11.741 (6), b = 16.15 5 (5), c = 25.895 (7) a ngstrom, V = 4912 angstrom3, T = 296 K, Z = 4, M(r) = 950.01, D(x) = 1 .28g cm-3, F(000) = 1992, Mo Kalpha, lambda = 0.7107 angstrom, mu = 0. 84 cm-1, R = 0.0538 for 2410 independent reflections with I > 0, S = 2 .29 for 2610 total reflections.