O. Borbulevych, R. D. Clark, Angel H. Romero
Jan 23, 2002
Citations
0
Influential Citations
35
Citations
Journal
Journal of Molecular Structure
Abstract
Abstract Molecular and crystal structure of a series of derivatives of N , N -dimethyl-4-nitroaniline has been studied by both X-ray diffraction method and high-level ab initio calculations. According to these data, the dimethylamino groups were found to have a trigonal-pyramidal configuration and are considerably turned with respect to the ring plane in all molecules having a substituent in the ortho -position; on the contrary, this group is planar in the meta -substituted molecules. Topological analysis of the electron density function for all molecules studied within the framework of Bader's ‘atoms in molecules’ (AIM) theory revealed that introduction of a substituent into the ortho - or meta -position of the ring results in increasing of the contribution of the resonance forms different from the quinoid one. Contribution of the latter form is predominant for the structure of N , N -dimethyl-4-nitroaniline ( 1 ). Topological analysis of the electron density distribution was used to explain a decreasing of the molecular hyperpolarisabilites of the ortho - and meta -substituted compounds as compared with those for 1 .