CRYSTAL-STRUCTURES OF [PB(NO3)6]4- AND [BA(NO3)6]4- SALTS OF 24-PYRIMIDINIUM CROWN 6 (5,12,19,26,33,40-HEXAAMINO-3,10,17,24,31,38-HEXAMETHYL[1.6](1,5)PYRIMIDINIOPHANE)

Reflux of thiamin [3-(4-amino-2-methylpyrimidin-5-ylmethyl)-5-(2-hydrooxyethyl)-4-methylthiazoliu m] mononitrate in methanol for 2h, followed by recrystallization from water, produced single crystals of [L][NO3]6 {L = 5,12,19,26,33,40-hexaamino-3,10,17,24,31,38-hexamethyl[1.6](1,5)-pyrimidiniopha ne or 24-pyrimidinium crown 6}. Addition of a saturated aqueous solution of M(NO3), (M = Ba or Pb) to a saturated aqueous solution of [L][NO3]6 yielded single crystals of [L] [Ba(NO3)6] [NO3]2.6H2O and [L][Pb(NO3)6] [NO3]2.6H2O respectively. Both compounds crystallize in the trigonal space group R3BAR: Ba, a = b = 14.265(3), c = 25.206(9) angstrom, Z = 3, R = 0.0435, R' = 0.0586, 1169 independent reflections with F > 6.0sigma(F); Pb, a = b = 14.228(5), c =25.24(1) angstrom, Z = 3, R = 0.0343, R' = 0.0354, 1263 independent reflections with F > 1.0sigma(F). The M2+ ions in these isomorphous structures lie on a three-fold axis and are co-ordinated to 12 nitrate oxygen atoms, with a co-ordination polyhedron resembling a distorted cuboctahedron.