Structural and Electronic Properties of Push-Pull Conjugated Molecules: A Theoretical Investigation of p-Amino-p’-Nitrodiphenylacetylene Compounds

We present and discuss the results of calculations carried out at the ab initio and AM1 semi-empirical levels, in order to rationalize the experimental data obtained by Graham et al. [1] on the series of donor-acceptor molecules NO2-C6H4-(C≡C)n-C6H4-NH2 with n=0-3. Full geometry optimizations on all the molecules are compared to the X-ray diffraction data. Evolution of the electronic properties as a function of the number of triple bonds between the phenyl rings is investigated.