Neutron Diffraction Study of 4-nitroaniline at 100K

C.G. POZZI; A.E. GOETA; G. PUNTE; E. DE MATOS GOMES; M. BELSLEY; G.J. MCINTYRE

Florencia, Italia

Congreso; XX IUCr Congress; 2005

The planarity of the amino group in nitroanilines is still a matter of controversy. It has been assumed in several experimental and theoretical studies of 4-nitroaniline (pNA) [1]. Single crystal X-ray diffraction and experimental electron density analysis of pNA have been previously reported [2,3]. However, no accurate experimental coordinates and atomic displacement parameters (adps) for the hydrogen atoms are available yet. As shown by Bürgi et al. [4], accurate adps for hydrogen atoms are essential for obtaining reliable results on physical properties. With this in mind, we have carried out a single crystal neutron diffraction study of pNA at 100K. It shows a relationship between the planarity of the amino moiety and the degree of intramolecular charge transfer, as well as a hydrogen bond scheme different from that observed in other primary anilines [1].