STUDIES ON POLYHALIDES .16. PREPARATION AND CRYSTAL-STRUCTURES OF BIPYRIDINIUMPOLYIODIDES BIPY.HIN WITH N=3, 5, AND 7

With simply protonated alpha,alpha'-Bipyridyl Bipy.H+ a triiodide Bipy. HI3, a pentaiodide Bipy.HI5 and a heptaiodide Bipy . HI7 may be prepared in the presence of iodide ions I- and dependent of the iodine I2 content. Bipyridiniumtriiodide C10H9N2I3 crystallizes at room temperature monoclinically in P2(1)/n with a = 1122.8 (1) pm, b = 1072.7(1) pm, c = 1200.2(3)pm, beta = 98.02(2)degrees and Z = 4. The crystal structure is built up from mixed cationic and anionic layers. Bipyridiniumpentaiodide C10H9N2I5 crystallizes at room temperature monoclinically in P2(1)/c with a = 887.3(5) pm, b = 2527.9(12) pm, c = 830.7(3) pm, beta = 106.78(5)-degrees and Z = 4. The crystal structure contains triiodide ions I3- till now uniquely connected by iodine molecules I2 in a trigonal planar way. Bipyridiniumheptaiodide C10H9N2I7 crystallizes at room temperature triclinically in P1 with a = 713.1(3) pm, b = 1 007.9(3) pm, c = 1464,8(4) pm, alpha = 81.07(3)-degrees, beta = 89.92(3)-degrees, gamma = 82.77(3)degrees and Z = 2. The crystal structure contains a V-shaped pentaiodide ion I5- completed by an iodine molecule I2 to a trigonal pyramidally shaped heptaiodide ion I7- and at the same time connected to a zigzag chain.