TETRAMETHYLPYRAZINIUM POLYIODIDES

(1): Tetramethylpyrazinium triiodide tetramethylpyrazine, C12H19N3I3, M(r)= 586.00, triclinic, P1, a = 8.226(3), b = 8.393(3), c = 13.878(6)Angstrom, alpha 85.28(3), beta = 74.54(3), gamma = 87.96(3)degrees, V = 920.2(6)Angstrom(3), Z = 2, D-x = 2.12gcm(-3), lambda(Mo K alpha) = 0.71073 Angstrom, mu = 50.9 cm(-1), F(000) = 542, T = 293 +/- 1K, R=0.033 for 2476 unique observed reflections. (2): Tetramethylpyrazinium triiodide.0.5methylhydroquinone.0.5methylquinone, C15H20N2O2I3, M(r) = 641.03, monoclinic, P2(1)/n, a = 7.679(2), b = 12.520(4), c = 10.774(3)Angstrom, beta = 100.60(2)degrees, V = 1019.9(6)Angstrom(3), Z = 2, D-x = 2.09 g cm(-3), lambda(Mo K alpha) = 0.71073 Angstrom, mu = 46.0 cm(-1), F(000) = 598, T = 293 +/- 1K, R = 0.086 for 1267 unique observed reflections. (3): Tetramethylpyrazinium pentaiodide-hydrate, C8H15N2OI5, M(r) = 789.72, triclinic, P1, a = 8.206(1), b = 9.228(2), c = 13.936(2)Angstrom, alpha = 77076(2), beta = 85.23(1), gamma = 65.88(1)degrees, V = 941.2(3)Angstrom(3), Z = 2, D-x = 2.79 g cm(-3), lambda(Mo K alpha) = 0.71073 Angstrom, mu = 82.5 cm(-1), F(000) = 700, T = 293 +/- 1K, R = 0.048 for 2753 unique observed reflections. Crystallizes as integrated stacks of alternating organic cations and I-3(-) anions. Pairs of stacks are bridged by neutral tetramethylpyrazine molecules through N-H ... N hydrogen bonding. In (2), similar stacks of cations and I-3(-) anions are formed, but are bridged in an extended fashion through hydrogen bonding by methylquinone (N-H ... O) and methylhydroquinone (O-H ... N) molecules. (3) crystallizes as a sheet structure with localized regions of monoprotonated cations bridged by water molecules into infinite hydrogen-bonded chains and polyiodide regions of branched chains of closely associated I-2 molecules and I-3(-) anions.