Tetraalkylammonium Tetrachlorothallates (III); X-Ray, ³⁵Cl-NQR, and ¹H-NMR Studies

Abstract

T e tra a lk y la m m o n iu m T e tr a c h lo r o th a lla te s ( I I I ) ; X -R a y , 35C 1 -N Q R , a n d XH -N M R S tu d ie s The crystal structure of (CH3)4NT1C14 and (C2H5)4NT1C14 was determined at room temperature by single crystal technique. (CH3)4NT1C14: D^-Cmmm; Z = 2; a = 913.2pm, fe = 894.6 pm, c = 752.5 pm; (C2H5)4NT1C14: Ct-P63mc; Z = 2; a = 827.9 pm, c = 1329.8 pm. (C2H5)4NT1C14 is isomorphous with (C2H5)4NInCl4. The compounds undergoe a phase transition at 239 K and 222 K, respectively. For both compounds no Cl NQR signal was observable in the high temper ature phase I due to the dynamics of the anion. The 3 Cl NQR was studied in the low temperature phase II of both compounds as a function of temperature. (CH3)4NT1C14 shows a two line, (C2H5)4NT1C14 a four line spectrum. The possible phase II structures and the dynamics of the cation, studied by 'H-NMR, are discussed.

Phase transition sequences in tetramethylammonium tetrachlorometallates by X-ray diffraction and spectroscopic measurements

“…Gó śniowska and colleagues report calorimetric data which suggest three first-order transitions for tetramethylammonium tetrabromoindate(III), [NMe 4 ][InBr 4 ], although structures of the transformed phases were not reported (Gó śniowska et al, 2000). NMR data indicate that tetramethylammonium tetrachlorothallate(III) undergoes a single phase transition at 239 K (Lenck et al, 1991).…”

Phase transition and structures of the twinned low-temperature phases of (Et4N)[ReS4]

“…Àh,k,Ài;l 0.233 (7) 6[9] m (2x,x,z) Ài,k,Àl;h 0.212 71988), Et 4 NFeBrCl 3 (Evans et al, 1990), Et 4 NInCl 4 (Trotter et al, 1969) and Et 4 NTlCl 4 (Lenck et al, 1991). They crystallize in the space group P6 3 mc.…”

Secondary Periodicity in the Tetrahalogeno Complexes of the Group 13 Elements

“…[15] The B-F distance is the average of the distances in Me 4 N[BF 4 ], [16] Me 3 PhN [BF 4 ] [17] and Pr 4 N[BF 4 ], [18] whereas the Al-F distance is that in Ph 4 P[AlF 4 ]. [19] Comparison of the average Tl-Cl distance in the tetramethylammonium salt [20] with that in the tetrabutylammonium salt [8] (2.416 Å and 2.393 Å, respectively) and of the Al-Cl distance in the LiAlCl 4 and CsAlCl 4 salts [21] (2.137 Å and 2.119 Å) shows that the effect of the cation on the M-X distance is within about 0.02 Å. This makes it possible to study the secondary periodicity in the M-X distance using the data from MX 4 -salts of different cations.…”