STRUCTURES OF 2 ACYLPYRIDINIUM SALTS AND ONE SIMPLE PYRIDINIUM SALT

N-Phenoxycarbonyl-4-dimethylaminopyridinium chloride (1), C14H15N2O2+.Cl- , M(r) = 278.7, monoclinic, P2(1)/c, a = 17.397 (4), b = 5.865 (2), c = 13.482 (5) angstrom, beta = 104.26 (2)-degrees, V = 1333.2 angstrom3, Z = 4, D(x) = 1.389 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 2.83 cm-1, F(000) = 584, T = 198 K, [GRAPHICS] R = 0.0486 for 2631 unique reflections with I > 2sigma(I). N-Benzoyl-4-dimethylaminopyridinium tetraphenylborate (II), C14H15N2O+.B(C6H5)4-, M(r) = 546.5, triclinic, P1BAR, a = 9.086 (2), h = 9.328 (2), c = 19.494 (5) angstrom, alpha = 79.03 (2), beta = 78.83 (2), gamma = 64.53 (2)-degrees, V = 1452.6 angstrom3, Z = 2, D(x) = 1.249 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 0.69 cm-1, F(000) = 580, T = 172 K, R = 0.051 1 for 5033 unique reflections with I > 4sigma(I). 4-Dimethylaminopyridinium chloride (III), C7H11N2+.Cl-, M(r)=158.6, monoclinic, C2/c, a = 17.113 (3), b = 7.460 (2), c = 14.570 (3) angstrom, beta = 120.84 (1)-degrees, V = 1597.0 angstrom3, Z = 8, D(x) = 1.319 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 4.03 cm-1, F(000) = 672, T = 192 K, R = 0.0462 for 1501 unique reflections with I > 3sigma(I). (I) and (II) are N-acylpyridinium salts; (III) is a pyridinium salt for comparative purposes. In compound (I), the C(9) atom of the phenyl ring, the oxycarbonyl group [O(2)-C(8)-O(1)] and the pyridinium moiety are all essentially coplanar; this is demonstrated in the torsional angles: O(1)-C(8)-N(1)-C(7) = -6.7 (3), C(1)-N(1)-C(8)-O(2) = - 1.1 (3), C(9)-O(2)-C(8)-O 1) = 6.1 (4) and C(9)-O(2)C( 8)-N(1) = - 176.8 (2)-degrees. The coplanarity of the carbonyl group with the pyridinium moiety in (1) is in contrast to that observed in (11); the torsional angle in (11) for 0(1)-C(8)-N(1)-C(7) is - 18.9 (2)-degrees. The benzoyl group of (II) is non-planar with a torsional angle C(14)-C(9)-C(8)-O(1) = - 32.3 (3)-degrees. The phenyl group in (I) is rotated out of the plane defined by the oxycarbonyl group: C(14)-C(9)-O(2)-C(8) = 61.4 (3)-degrees. The simple pyridinium salt (III) is unexceptional. The only interesting feature is the position of the Cl anion relative to the N [GRAPHICS] atom in the compound. The Cl ions are situated in the crystal lattice such that they are disposed 0.4 angstrom closer to N(1) than to N(2): N(1)-Cl(1) = 3.065 versus N(2)-Cl(1) = 3.469 angstrom.