On the impact of a phosphoryl group in the recognition capabilities of 2-aminopyridines toward carboxylic acids
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.
KeywordsMolecular recognition Amino–imino tautomerization Fluorescence 2-aminopyridines
We acknowledge financial support form Spanish MINECO/FEDER, Grants CTQ2015-65790-P and CTQ2016-76829-R and Principado de Asturias Government Grant FC-GRUPIN-IDI/2018/000117. C. C. expresses her gratitude to MINECO for the award of “Ramón y Cajal” contract (RYC-2014-16021). AFA thanks CONACyT/México for his scholarship 436154. We also thank Dr. P. Braña for fruitful discussions.
- 37.Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR, Scalmani G, Barone V, Mennucci B, Petersson GA, Nakatsuji H, Caricato M, Li X, Hratchian HP, Izmaylov AF, Bloino J, Zheng G, Sonnenberg JL, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Vreven T, Montgomery JA Jr, Peralta JE, Ogliaro F, Bearpark M, Heyd JJ, Brothers E, Kudin KN, Staroverov VN, Kobayashi R, Normand J, Raghavachari K, Rendell A, Burant JC, Iyengar SS, Tomasi J, Cossi M, Rega N, Millam JM, Klene M, Knox JE, Cross JB, Bakken V, Adamo C, Jaramillo J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli C, Ochterski JW, Martin RL, Morokuma K, Zakrzewski VG, Voth GA, Salvador P, Dannenberg JJ, Dapprich S, Daniels AD, Farkas Ã, Foresman JB, Ortiz JV, Cioslowski J, Fox DJ (2009) GaussianâĹij09 Revision E.01. Gaussian Inc., Wallingford, CTGoogle Scholar
- 43.Khan MFS, Wu J, Liu B, Cheng C, Akbar M, Chai Y, Memon A, Soc R (2018) Open Sci 5(2):171719Google Scholar