Mesomeric effect on the structural and electronic properties of 4-(2-tert-butyl-4-methylphenoxy)phthalonitrile

Abstract

The molecular and crystal structures of the title compound, C 19 H 18 N 2 O, were determined and characterized by single crystal X-ray diffraction and spectroscopic methods. Details of the molecular geometry imply that there is a mesomeric effect between the electron-withdrawing N atoms of nitrile substituents and electrondonating O atom. Formally, single central O-C ar bond lengths are considerably different from each other. O-C ar distance to phthalonitrile ring is shorter than the other O-C ar distance due to mesomeric effect under discussion. In addition to structural and spectral evidences, possible results from mesomerism of the compound were investigated by topological analysis on the electronic properties using quantum theory of atoms in molecules (QTAIM) approach. It is inferred from topological analysis that the nitrile group in para position has slightly stronger mesomeric effect than that in meta position due to diffusive double charge separation property during meta mesomerism of the compound. Mesomeric effect revealing itself by differences in delocalization indices between certain bonded atom pairs results in considerable decrease in aromaticity of phthalonitrile ring.

Synthesis, characterization and spectroscopic studies of novel peripherally tetra-imidazole substituted phthalocyanine and its metal complexes, the computational and experimental studies of the novel phthalonitrile derivative

“…C Ar eO stretching vibrations calculated at the range of 1224e1149 cm À1 were in good agreement with the experimental data and literature [57].…”

“…The experimental C^N stretching mode was observed at 2230 cm À1 as a single sharp band while in theoretical C^N stretching vibrations were observed as a sharp and intense band at 2244 and weak shoulder at 2251 cm À1 [57]. The low intense band at 2251 cm À1 was not observed in the experimental spectrum.…”

“…C]C aromatic stretching vibrations calculated at a range of 1574e1393 cm À1 were in good agreement with the experimental data at a range of 1595e1423 cm À1 . Due to the dense C]C phenyl stretching vibrations, C]N stretching vibrations were observed together with C]C aromatic stretching vibrations at 1574 and 1531 cm À1 [52,54,57].…”

Effects of pnictogen and chalcogen bonds on the aromaticities of carbazole-like and dibenzofuran-like molecular skeletons: Cambridge Crystallographic Data Centre (CCDC) Study

“…Substitution of an aromatic system mostly leads to a decrease in its aromaticity. Because electronic delocalization from more movable electrons along conjugated path is directly responsible for the extra stabilization of an aromatic system, the substituent effects are considered as a kind of perturbation in aromaticity due to mesomeric effects . Aromatic systems, although acting as a medium in electronic charge interchange between the substituent groups, may also restrict this interaction to a certain extent because of its tendency of preserving aromatic character.…”

Interplay of thermochemistry and Structural Chemistry, the journal (volume 21, 2010) and the discipline

“…Karabıyık et al [304] studied spectroscopic properties and molecular and X-ray single crystal structure of 4-(2-tert-butyl-4-methylphenoxy)phthalonitrile. A mesomeric effect between the electron-withdrawing N atoms of nitrile substituents in meta and para positions and the electron donating O atom was identified, which should be, as revealed by QTAIM slightly stronger in para than in meta position.…”