STRUCTURE OF THIOCYANATE SALT OF 1,8-BIS(DIMETHYLAMINO)NAPHTHALENE (DMANH+.SCN-) AT 188 AND 290 K

The structure of the title compound has been determined by X-ray diffraction techniques at 188 and 290 K. Crystal data for C14H19N2+.SCN-(dmanH+.SCN-): M(r) = 273.40, orthorhombic, Pbcn, Z = 4, F(000) = 584; (I) T = 188 K, lambda(Mo Kalpha) = 0.71073 angstrom, mu = 1.97 cm-1, a = 8.033 (1), b = 22.770 (6), c = 8.193 (1) angstrom, V = 1498.5 (3) angstrom3, D(x) = 1.212 g cm-3, R(F2) = 0.047 for 2280 reflections; (II) T = 290 K, lambda(Cu Kalpha) = 1.54178 angstrom, mu = 17.5 cm-1, a = 8.0608 (9), b = 22.941 (3), c = 8.266 (2) angstrom, V = 1528.5 (4) angstrom3, D(x) = 1.188, D(m) = 1.180 g cm-3, R(F) = 0.063 for 1026 reflections. The dmanH+ cation has crystallographic twofold symmetry. The thiocyanate anion is disordered around another two-fold axis. The short intramolecular N...H...N hydrogen bond between the amino groups is statistically symmetrical, with H+ on the twofold axis (according to the least-squares refinements). The geometry of the N...H...N bridge is characterized by N...N 2.573 (3) and 2.566 (3) angstrom and N...H...N 156 (2) and 160 (2) at 188 and 290 K, respectively. This distance is close to the estimated lower limit of N...N hydrogen bonds, where truly symmetric bonds may be expected.