Fabry, Jan published the artcileHigh- and low-temperature phases in isostructural 4-chloro-3-nitroaniline and 4-iodo-3-nitroaniline, Formula: C6H5IN2O2, the main research area is chloronitroaniline iodonitroaniline temperature isostructure phase; 4-chloro-3-nitroaniline; 4-iodo-3-nitroaniline; Raman; crystal structure; geometric constraints; phase transitions.
The structures of 4-chloro-3-nitroaniline, C6H5ClN2O2, (I), and 4-iodo-3-nitroaniline, C6H5IN2O2, (II), are isomorphs and both undergo continuous (second order) phase transitions at 237 and 200 K, resp. The structures, as well as their phase transitions, have been studied by single-crystal X-ray diffraction, Raman spectroscopy and difference scanning calorimetry experiments Both high-temperature phases (293 K) show disorder of the nitro substituents, which are inclined towards the benzene-ring planes at two different orientations. In the low-temperature phases (120 K), both inclination angles are well maintained, while the disorder is removed. Concomitantly, the b axis doubles with respect to the room-temperature cell. Each of the low-temperature phases of (I) and (II) contains two pairs of independent mols., where the mols. in each pair are related by noncrystallog. inversion centers. The mols. within each pair have the same absolute value of the inclination angle. The Flack parameter of the low-temperature phases is very close to 0.5, indicating inversion twinning. This can be envisaged as stacking faults in the low-temperature phases. It seems that competition between the primary amine-nitro N-H···O hydrogen bonds which form three-centered hydrogen bonds is the reason for the disorder of the nitro groups, as well as for the phase transition in both (I) and (II). The backbones of the structures are formed by N-H···N hydrogen bonding of moderate strength which results in the graph-set motif C(3). This graph-set motif forms a zigzag chain parallel to the monoclinic b axis and is maintained in both the high- and the low-temperature structures. The primary amine groups are pyramidal, with similar geometric values in all four determinations The high-temperature phase of (II) has been described previously [Garden et al. (2004). Acta Crystalline C60, o328-o330].
Acta Crystallographica, Section C: Structural Chemistry published new progress about Crystal structure. 105752-04-3 belongs to class iodides-buliding-blocks, name is 4-Iodo-3-nitroaniline, and the molecular formula is C6H5IN2O2, Formula: C6H5IN2O2.
Referemce:
Iodide – Wikipedia,
Iodide – an overview | ScienceDirect Topics – ScienceDirect.com