Virtual Issue on Multifunctional Nanoporous Materials in Latin America

GOMEZ, GERMÁN E.; SOLER-ILLIA, GALO J. A. A.

CHEMISTRY OF MATERIALS

AMER CHEMICAL SOC

Año: 2021 vol. 33 p. 7569 - 7571

0897-4756

Latin America is a vibrant and ethnically diverse land, with a unique culture characterized by ingenuity and creativity. Although lagging behind in scientific infrastructure and developments, and with a huge disparity in production, our region proudly displays Nobel Prize laureates in chemistry (L. F. Leloir and M. Molina) and medicine (B. Houssay, C. Milstein, and B. Benacerraf Bolaños). Latin American chemists are living proof of the old proverb: ?necessity is the mother of invention?, being used to survive in hostile economic and bureaucratic labyrinths. Formed under stringent conditions, they bloom all over the world and are able to produce remarkable science. The Latin community is expanding and networking in global events such as the successful #LatinXChem virtual conference, which hosted more than 1,000 posters in a Twitter platform in 2020 and will be repeated in 2021. This is a positive action toward improving the chemistry landscape and favoring inclusion of the region. (1)In this Virtual Collection, we highlight recent papers from Latin American research groups devoted to microporous and mesoporous multifunctional materials. This field is of recent development within materials chemistry and exemplifies the growth of a dynamic community. We made a coarse division in two different areas: metal?organic frameworks (MOFs) and templated microporous, mesoporous, or macroporous materials or composites.MOFs constitute a unique class of supramolecular compounds built of metal ions connected by organic ligands. The broad variety of unique crystalline architectures obtained is a promising platform for a variety of applications. Efforts are driven toward biocompatible MOFs that permit direct applications in drug delivery (2) or the adsorption of hazardous compounds. (3) Interestingly, particular microporous systems present a semilabile coordination, which can be advantageously used in corrosive gas sorption; (4) in some cases, the chemisorbed reactive gas species can even polymerize. (5) This last feature has deep implications in confined catalysis, with prospective application in batteries. (6)An adequate choice is luminescent lanthanide ions presenting well-defined optical transitions (7) with antenna-like linkers that permit color tuning and improve photoluminescence. Highly stable MOFs with robust emission signals can be used for solid-state lighting, thermal-sensing, (8) or markers of gunshot residues in forensics, (9) with low toxicity. (10) Interestingly, new models that predict the optical properties of ligands in the presence of ions have been developed, opening the way to pretailored optically active MOFs. (11)MOF thin films that combine size-dependent properties with functionalized substrates lead to nanotechnological devices. For example, zeolitic imidazole framework (ZIF-8) thin films are effective size-dependent molecular carriers (12) or enable biosensing of protein?protein interactions. (13) Several works combining microscopy and spectroscopy have demonstrated that subtle interactions between the MOF building blocks and the substrates are crucial in the formation of 2D supramolecular networks (14,15) and 2D open structures (16) anchored onto solid substrates.Research in templated pore systems is nowadays aiming at achieving predictable synthesis of nanopore structures and elucidating their complex transport, sorption, and catalytic features. A theoretical?experimental approach permitted the designed and predictable synthesis of mesoporous layered M(II) hydroxide thin films with energy applications. (17)The importance of understanding molecules under confinement is illustrated by recent findings where transport, sorption, and size-selective catalytic properties of aluminosilicates such as ZSM-5 and its low-crystallinity precursors are critically dependent on pore size and connectivity which, in turn, can be kinetically controlled through synthesis. (18) Unusual nanofluidic effects have been found due to dynamic processes taking place in salt solutions confined within mesoporous thin films. (19,20) Open macroporous structures facilitate interactions between electroactive species and catalytic sites, permitting novel electrodes for Zn?air batteries. (21)Surface functionalization of mesoporous silica nanoparticles is critical for biomedical treatments, either for colloidal stability and dispersibility, (22) or for improved immobilization of functional enzymes. (23)Finally, several works were dedicated to emerging composites that combine porous materials and polymeric matrices. Abatement of contaminants in aqueous media has been reported using porous cellulose-natural rubber latex, (24) macroporous polyacrylamide/γ-Fe2O3 adsorbents, (25) or cellulose/MoS2 aerogels as bifunctional adsorbent/photocatalyst membranes. (26) MOF@carbon hybrid composites were also reported in the adsorption of emerging contaminants in aqueous media. (27) Among energy applications, graphene/metallic NP aerogel composites demonstrated potential in hydrogen storage. (28) A breath-figure method of patterning led to electroactive thin films with gating properties, due to the combination of porous graphene with thermoresponsive polymers. (29)In conclusion, this Virtual Collection is a showcase of the dynamic activities in nanoporous materials in Latin America. The main emerging directions point at exploiting the multifunctionality of the structural building blocks, as well as understanding in-depth the role of pores, necks, and surfaces for molecular storage, transport, or reactivity under confinement. Applications are mainly focused in environment, health, and energy fields, which are relevant in the social context. It is worth noting that many of these works make use of international collaborations, which relieves the economic and infrastructure barriers to materials chemistry that still exist in the region. The future commissioning of facilities such as the Sirius synchrotron in Brazil and the LAHN neutron source in Argentina will undoubtedly foster opportunities to achieve sophisticated characterization techniques, including operando experiments.These selected articles show exciting perspectives for the upcoming future of porous materials in the region. A consolidation of the materials chemistry community is evident, leading to the formation of highly trained scientists and providing an outlook to future industrialization of the upcoming technologies. These two aspects are essential. Sound science and technology are key to creating long-term economic opportunities for the young generation, which is the most crucial societal challenge nowadays in the region.