On the impact of a phosphoryl group in the recognition capabilities of 2-aminopyridines toward carboxylic acids

• Published in: Theoretical chemistry accounts 2019-09, Vol.138 (9), p.1-9, Article 112
• Main Authors: Gallegos, Miguel, Gil-Guerrero, Sara, Fernández-Alarcón, A., Bouzas-Ramos, Diego, Martín, Judith, Concellón, Carmen, del Amo, Vicente, Costa, J. M., Mendoza-Meroño, R., García-Granda, S., Martín Pendás, Ángel, Costales, Aurora
• Format: Article
• Language: English
• Subjects: 11th Congress on Electronic Structure: Principles and Applications (ESPA-2018); Atomic/Molecular Structure and Spectra; Carboxylic acids; Catalysis; Chemistry; Chemistry and Materials Science; Density functional theory; Inorganic Chemistry; Organic Chemistry; Physical Chemistry; Recognition; Regular Article; Response time; Theoretical and Computational Chemistry; Time dependence
• ISSN: 1432-881X; 1432-2234
• DOI: 10.1007/s00214-019-2496-0

Inspired by natural molecular recognition processes, many research efforts have been routed in recent years toward the design of new host–guest molecular systems based on non-covalent interactions. Within this field, 2-aminopyridines (2APs) have been widely studied due to their tunable spectroscopic response in the presence of carboxylic acids. Herein, we present and analyze a novel family of 2AP core compounds based on 2-phosphorylamidopyridine (2PAP). Linear response time-dependent density functional theory (TD-DFT) has been used to characterize and model several spectroscopic properties of 2PAP. Our results, validated through experiments, show that TD-DFT can provide a reliable description of the electronic excited states of these aromatic systems. In addition, we have also studied the amino–imino tautomerization of 2AP and 2PAP in light of TD-DFT tools. We show that the presence of a carboxylic acid has a catalytic effect on the tautomerization reaction, which otherwise does not occur spontaneously at room temperature. These results suggest that this low-cost computational approach can be applied to more complex organic systems derived from 2-aminopyridine, paving the way for the development of potentially useful sensing materials and organic species for molecular recognition.