Monocolor chemosensors for Ba2+ tagging experiments

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.The BOLD experiment is focused on the observation of the neutrinoless double β decay of 136Xe to 136Ba2+ through the detection of the daughter cation. For this purpose, different molecular sensors can be developed. These chemosensors can be classified into monocolor (offon) or bicolor (on-on’), depending on the shifts (Δλ) and changes in the intensity (ΔI) observed in their emission spectra. In this context, different off-on radiometric chemosensors have been synthesized in order to understand their photophysics upon interaction with Ba2+ ions in vacuo and in solution. These sensors incorporate two components: a fluorophore and a metal-binding group. The fluorophores are kept as simple as possible, using structures with well-known photophysical properties. On the other hand, N-aza-crown ether derivatives have been used as metal-binding groups. Finally, the effects of disconnecting the abovementioned elements by splitting of components Ar1 and Ar2 (Figure 1: Description of the off-on chemosensors synthesized in this work), will be discussed.Financial support from the Basque Government (IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe

New generation of fluorescent bicolour sensors for barium tagging experiments

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.One of the most important questions in particle physics and cosmology consists of demonstrating that the neutrino is a Majorana fermion. Observation of the neutrinoless double β decay of 136Xe to generate the daughter cation 136Ba2+ is the most promising practical way to demonstrate this hypothesis. Within this context, our research group has designed and synthesized the first generation of fluorescent bicolour sensors (FBI-G1), whose emission spectra change upon binding to Ba2+ ions by formation of supramolecular complexes in dry media involving solid-gas interphases. In this presentation, the synthesis of a second generation (G2) of bicolour sensors is reported. These sensors have two essential components, a metal-binding group, and a fluorophore. The latest structure is based on a benzo[a]imidazo[2,1,5-cd]indolizine derivative (Figure 1: Description of generation 1 (left) and generation 2 (right) chemosensors). Finally, preliminary research involving the linkage of our sensors to surfaces such as indium tin oxide glass (ITO), will be discussed.Financial support from the Basque Government (IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe

Iridium-based sensor for cations

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.Traditionally, techniques such as inductively coupled plasma mass spectroscopy or gas chromatography have been used for cation detection. However, these methods need long analysis times and sophisticated instrumentation. Simpler and faster methods have been developed these days, such us optical methods (colorimetric and/or fluorescent), which can entail easy visualization, high sensitivity and cheaper instrumentation. Among these, ratiometric (bicolour) fluorescent sensors stand out due to the lower limit of detection. In this area, both organic molecules and metal complexes are being developed as luminescent probes. Indeed, some iridium complexes demonstrated to be selective luminescent sensors for different cations. Different strategies are used to trap or interact with the cation, which permits a rational tuning of the iridium’s emission. In our group, we have been working with iridium complexes for a variety of objectives. In this contribution, an iridium-based sensor for cations will be described including its response to cations in solution and on solid supports.Financial support from the Basque Government (PRE_2020_2_0230, IT-1346-19 and IT-1180-19), the Spanish MICINN (PID2019-104772-GB-I00, PID2019-111281-GB-I00, RED2018-102387-T, and RED2018-102471-T), and by the European Commission (ERC-2020-SyG-951281) is gratefully acknowledged.Peer reviewe

Ba+2 ion trapping using organic submonolayer for ultra-low background neutrinoless double beta detector

If neutrinos are their own antiparticles the otherwise-forbidden nuclear reaction known as neutrinoless double beta decay can occur. The very long lifetime expected for these exceptional events makes its detection a daunting task. In order to conduct an almost background-free experiment, the NEXT collaboration is investigating novel synthetic molecular sensors that may capture the Ba dication produced in the decay of certain Xe isotopes in a high-pressure gas experiment. The use of such molecular detectors immobilized on surfaces must be explored in the ultra-dry environment of a xenon gas chamber. Here, using a combination of highly sensitive surface science techniques in ultra-high vacuum, we demonstrate the possibility of employing the so-called Fluorescent Bicolor Indicator as the molecular component of the sensor. We unravel the ion capture process for these molecular indicators immobilized on a surface and explain the origin of the emission fluorescence shift associated to the ion trapping.This material is based upon work supported by the following agencies and institutions: the European Research Council (ERC) under ERC-2020-SyG 951281; the MCIN/AEI/10.13039/501100011033 of Spain and ERDF A way of making Europe under grants PID2020-114252GB-I00, PID2019-107338RB-C63, PID2019-104772GB-I00, PID2019-111281GB-I00, and RTI2018-095979, the Severo Ochoa Program grant CEX2018-000867-S; the Basque Government (GV/EJ) under grants IT-1553-22, IT-1591-22. The NEXT Collaboration acknowledges support from the following agencies and institutions: the European Union’s Framework Programme for Research and Innovation Horizon 2020 (2014-2020) under Grant Agreement No. 957202-HIDDEN; the MCIN/AEI of Spain and ERDF A way of making Europe under grants RTI2018-095979 and PID2021-125475NB, the Severo Ochoa Program grant CEX2018-000867-S and the Ramón y Cajal program grant RYC-2015-18820; the Generalitat Valenciana of Spain under grants PROMETEO/2021/087 and CIDEGENT/2019/049; the Department of Education of the Basque Government of Spain under the predoctoral training program non-doctoral research personnel; the Portuguese FCT under project UID/FIS/04559/2020 to fund the activities of LIBPhys-UC; the Pazy Foundation (Israel) under grants 877040 and 877041; the US Department of Energy under contracts number DE-AC02-06CH11357 (Argonne National Laboratory), DE-AC02-07CH11359 (Fermi National Accelerator Laboratory), DE-FG02-13ER42020 (Texas A&M), DE-SC0019054 (Texas Arlington) and DE-SC0019223 (Texas Arlington); the US National Science Foundation under award number NSF CHE 2004111; the Robert A Welch Foundation under award number Y-2031-20200401. Finally, we are grateful to the Laboratorio Subterráneo de Canfranc for hosting and supporting the NEXT experiment.Peer reviewe