SOLID-STATE BINDING OF DIMETHYL-SULFOXIDE INVOLVING CARBOXYLIC HOST MOLECULES - X-RAY CRYSTAL-STRUCTURES OF 4 INCLUSION SPECIES

The crystal structures of four dimethyl sulphoxide (DMSO) inclusion compounds with different carboxylic acid hosts, 1-4, have been studied by single crystal X-ray analysis. Crystals of the trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid inclusion compound (1a), [1 · DMSO (1: 1)] show monoclinic (P21/n) symmetry with the unit cell dimensions a = 11.522(4), b = 18.658(2), c = 8.709(1) Å and β = 98.92(2)°. The clathrate of the 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (2a), [2 · DMSO (1: 2)] is triclinic (PĪ) with the cell dimensions a = 15.043(7), b =9.657(4), c = 8.118(7) Å, α = 101.81(5), β = 96.05(4) and γ = 100.04(4)°. Triclinic (PĪ) symmetry is shown also by the inclusion compound of 9,10-dihydro-9,10-ethanoanthracene-11-monocarboxylic acid (3a) [3 · DMSO (1:1)] with the cell dimensions a=6.3132(1), b=7.9846(2), c=17.5314(4) Å, α = 96.46(2), β = 87.08(2) and γ = 106.02(2)°. The 9,9′-bianthryl-2-monocarboxylic acid clathrate (4a) [4 · DMSO (1:1)] is monoclinic (P21/n) and the cell dimensions are a = 19.625(18), b = 8.817(1), c = 14.076(8) Å and β = 97.92(6)°. In all these structures, the hosts show the same basic recognition pattern for the DMSO guest, involving a strong O-H ... O bond from the COON to the S=O group, and a possible C-H ... O type interaction between the carbonyl O atom of the host and a CH3 group of the guest. The crystals consist of discrete host-guest aggregates which are mainly held together by weak intermolecular interactions of the Van der Waals' type. The stoichiometries of the aggregates are, however, different. © 1990 Kluwer Academic Publishers.