Isomerism of the Aniline Trimer.

Isomerism of the Aniline Trimer.
Angew Chem Int Ed Engl. 2018 Oct 03;:
Authors: Perez C, León I, Lesarri A, Pate BH, Martínez R, Millán J, Fernández JA
Abstract
Weaker intermolecular forces permit expanded isomerization alternatives for molecular aggregation, as observed for the prototype models of the aniline trimer (An3) and the monohydrated aniline dimer (An2-W) when compared to the phenol trimer. These isolated trimers were generated in a jet-cooled neon expansion and probed using broadband (chirped-pulsed) microwave spectroscopy. Three isomers of the aniline trimer and two isomers of the hydrated dimer were detected and characterized in the spectrum. In the homotrimer the weak N-H···N hydrogen bonds are assisted by subtle combinations of N-H···Pi and C-H···Pi interactions, producing several competing low-lying ring species in the gas phase. One of the aniline trimers is a symmetric top, topologically equivalent to the only observed phenol trimer. Conversely, addition of a water molecule to the aniline dimer introduces a leading O-H···N interaction, making water to behave as dominant hydrogen-bond pivot between the two aniline molecules. This combination of weak intermolecular interactions critically tests the performance of dispersion-corrected or parametrized density-functional methods. Evaluation of the B3LYP-D3(BJ) and M06-2X methods revealed deficiencies of the Truhlar functional to reproduce the experimental...

Source: Angewandte Chemie - October 3, 2018 Category: Chemistry Authors: Perez C, León I, Lesarri A, Pate BH, Martínez R, Millán J, Fernández JA Tags: Angew Chem Int Ed Engl Source Type: research