GEOMETRY OF THE IMINIUM MOIETY .1. STRUCTURE OF PYRAZOLINIUM SALTS AND AN N-ISOPROPYLIDENE DERIVATIVE

Compound (I; PYCL), 4,5-dihydro-3,5,5-trimethylpyrazolium chloride, C6H13N2+.Cl-, M(r) = 148.64, orthorhombic, P2(1)2(1)2(1), a = 8.324 (1), b = 8.381 (1), c = 12.121 (1) angstrom, V = 845.60 (16) angstrom 3, Z = 4, D(m) = 1.17 (1), D(x) = 1.167 g cm-3, lambda-(Mo K-alpha) = 0.71073 angstrom, mu = 3.31 cm-1, F(000) = 320, T = 294 K, R = 0.030 for 782 observed reflections. Compound (II; PYRA), bis(4,5-dihydro-3,5,5-trimethylpyrazolium) hexachlorostannate monohydrate, 2C6H13N2+.SnCl6(2-).H2O, M(r) = 575.8, orthorhombic, Fdd2, a = 16.975 (2), b = 30.729 (4), c = 8.987 (10) angstrom, V = 4687.8 (27) angstrom 3, Z = 8, D(m) = 1.62 (1), D(x) = 1.631 g cm-3, mu = 16.5 cm-1, F(000) = 2304, R = 0.021 for 1927 observed reflections. Compound (III; PYCS), bis(4,5-dihydro-3,5,5-trimethyl-l-isopropylidenepyrazolium) hexachlorostannate, 2C9H17N2+.SnCl6(2-), M(r) = 637.9, monoclinic, C2/c, a = 14.145 (1), b = 11.630 (1), c = 17.054 (6) angstrom, beta = 98.71 (4)-degrees, V = 2773.1 (10) angstrom 3, Z = 4, D(m) = 1.52 (1), D(x) = 1.528 g cm-3, mu = 15.2 cm-1, F(000) = 1288, R = 0.027 for 1930 observed reflections. Compound (IV; MONS), M(r) = 654.8, cubic, Im3BAR, a = 17.886 (4) angstrom, V = 5721.9 (42) angstrom 3, Z = 8, D(m) = 1.52 (1), D(x) = 1.520 g cm-3, mu = 14.9 cm-1, F(000) = 2400, R = 0.069 for 644 observed reflections. The four structures arise from the condensation of hydrazine compounds with acetone. In (III) and (IV) the existence of the ternary iminium ion was confirmed. Strong hydrogen bonds exist in (I) and (II). (IV) is structurally disordered, containing an equal proportion of (II) and (III) and constraints were applied to several bond lengths of the rings during the final stages of refinement.