The recognition and detection of ionic species has aroused great interest due to their important roles in many biological and environmental processes. Colorimetric chemosensors are molecules that allow naked-eye detection of ionic species without resource to any instrumentation, offering qualitative and quantitative information and are considered as one of the most effective analytical method for environmental monitoring, particularly in the detection of metal ions whose presence in the environment has serious consequences.¹

Research of sensors with good sensitivity and good selectivity in aqueous medium has been of great interest. Chemosensors soluble in aqueous media are very interesting, because of the importance in revealing a number of biological processes, disease states and environmental pollutions.²

Hydrazone derivatives are versatile compounds with several applications such as in medicinal chemistry due to their vast biological activity and as optical (colorimetric and fluorimetric) sensing of anions and metal cations. Other applications in materials science include molecular switches, OLEDs, etc.³

In this communication, we report the synthesis of one hydrazone derivative, functionalized with an heterocyclic moiety, in order to evaluate its photophysical properties and chemosensory ability. The new derivative was characterized by the usual techniques and a detailed photophysical study was undertaken. The evaluation of the novel compound as a colorimetric chemosensor was carried out by performing titrations in acetonitrile and acetonitrile/water in the presence of relevant organic and inorganic anions, and of alkaline, alkaline-earth and transition metal cations.

Acknowledgements: Thank are due to Fundação para a Ciência e Tecnologia (Portugal) and FEDER-COMPETE for financial support through Centro de Química (UID/QUI/00686/2013 and UID/ QUI/0686/2016), and a PhD grant to R.C.M. Ferreira (SFRH/BD/86408/2012). The NMR spectrometer Bruker Avance III 400 is part of the National NMR Network and was purchased with funds from FCT and FEDER.

References:

1. a) Batista, R. M. F.; Costa, S. P. G.; Raposo, M. M. M. J. Photochem. Photobiol. A: Chem., 2013, 259, 33. b) Thakur, B.; Amarnath, C. A.; Mangoli, S. H.; Sawant, S. N. Sens. Actuat. B, 2015, 207, 262.
2. a) Patil, S.; Patil, R.; Fegade, U.; Bondhopadhyay, B.; Pete, U.; Suban, K. S.; Singh, N.; Basu, A.; Bendre, R.; Kuwar, A. Photochem. Photobiol. Sci., 2015, 14, 439. b) Udhayakumari, D.; Velmathi, S.; Boobalan, M. S.; Venkatesan, P.; Wu, S.-P. J. Luminescence, 2015, 158, 484. c) Alici, O.; Erdemir, S. Sens. Actuat. B, 2015, 208, 159. d) Hu, Y.; Zhang, J.; Lv, Y.-Z.; Huang, X.-H-; Hu, S.-li. Spectrochim. Acta Part A: Mol. Biomol. Spect., 2016, 157, 164.
3. (a) Raposo, M. M. M.; García-Acosta, B.; Ábalos, T.; Calero; P.; Martínez-Manez, R.; Ros-Lis, J. V.; Soto, J. J. Org. Chem., 2010, 75, 2922. b) Santos-Figueroa, L. E.; Moragues, M. E.; Raposo, M. M. M., Batista, R. M. F.; Ferreira, R. C. M.; Costa, S. P. G.; Sancenón, F.; Martínez-Máñez, R.; Ros-Lis, J. V.; Soto, J. Tetrahedron 2012, 68, 7179-7186. c) Santos-Figueroa, L. E.; Moragues, M. E.; Raposo, M. M. M., Batista, R. M. F.; Ferreira, R. C. M.; Costa, S. P. G.; Sancenón, F.; Martínez-Máñez, R.; Ros-Lis, J. V.; Soto, J. Org. Biomol. Chem. 2012, 10, 7418-7428. d) Marín-Hernández, C.; Santos-Figueroa, L. E.; Sayed S.; Pardo, T.; Raposo, M. M. M., Batista, R. M. F.; Costa, S. P. G.;  Sancenón, F. Martínez-Máñez, R. Dyes Pigments, 2015, 122, 50.