HALOGEN NQR AND CRYSTAL-STRUCTURE OF AMMONIUM HALIDES (R-NH3)- AND (X-) (+H3NR'NH3+) (X-) - R=(HOCH2)3C, R'=CH2C(CH3)2CH2 - X=I, BR(X)

The I-127-NQR of (HOCH2)3CNH3+I- was determined in the range 77 less-t han-or-equal-to T/K less-than-or-equal-to 310. At T = 310 K the NQR si gnal fades out (T(m) = 463 K). The I-127 spectrum(T = 77 K): nu1 = 29. 195 MHz, nu = 14.597 MHz, eta(I-127) = 0, e Q PHI(zz)h-1(I-127) = 97.3 15 MHz, is in agreement with the crystal structure. The I-127 NQR spec trum of 1,3-diammonium-2,2-dimethylpropane diiodide, (H3NCH2C(CH3)2 CH 2NH3)2+.2I-, is a quartet within the whole temperature range investiga ted, and the lines correspond to two crystallographically independent iodines: Space group P2(1)/c, Z = 4, a = 731.2(3) pm, b = 689.0(3) pm, c = 2255.1(8) pm, beta = 104.90(1)-degrees. At T = 77 K the I-127 NQR quartet is (MHz): nu1 = 34.145, nu2 = 32.805, nu3 = 22.113, nu4 = 16. 787; at 295 K (same order, MHz): 30.559, 29.729, 19.810, 15.651. There are two combinations of the NQR frequencies. Considering the coordina tion of I-, the hydrogen bonds N-H...I, e Q PHI(zz)Q h-1, and eta, we choose for I(1) nu1 and nu3, for 1(2) nu2 and nu4. At 77 K e Q PHI(zz) h-1 (I(1)) = 118.86 MHz, eta(I-127(1)) = 0.498, e Q PHI(zz)h-1 (I(2)) = 109.75 MHZ, eta(I-127(2)) = 0.135 follow for the two iodine atoms. B oth, e Q PHI(zz)h-1 (I(1)) and e PHI(zz)Q h-1 (I(2)) decrease smoothly with increasing T:eta(I(2)) increases with increasing T whereas eta(I -127(1)) is almost constant within 77 less-than-or-equal-to T/K less-t han-or-equal-to 406. The Br-79.Br-81 NQR spectrum of 1,3-diamino-2,2-d imethylpropane dihydrobromide is also a quartet, showing two crystallo graphic inequivalent Br atoms in the unit cell. The frequencies are (T = 273 K, M Hz): nu1 (Br-79) = 14.303, nu2(Br-79) = 12.884, nu1(Br-81) = 11.951, nu2(Br-81) = 10.781; space group C2/c, Z = 8, a = 2136.4(6) pm, b = 854.6(3) pm, c = 1 125.8(3) pm, beta = 93.23(1)-degrees. Crys tal structures and NQR results are discussed.