{The mechanism of cellulose dissolution in ionic liquid (IL)/dimethyl sulfoxide (DMSO) solvent systems has attracted much attention due to the possible replacement of synthetic materials. However, the solvent behaviour is not completely understood. This work has found an explanation for the solvent behaviour in cellulose dissolution, considering the almost unavoidable presence of the water. Ternary {[}C(4)mim] Cl/DMSO/H2O mixtures were studied with Nuclear Magnetic Resonance experiments and molecular dynamics simulations to explore IL/molecular solvents interactions and disclose the water interactions in these complex media. Titration of binary and ternary solvent systems with water and DMSO disclosed a relation between water's proton chemical shift and the molar fraction of the mixture components, creating an unprecedent theory to predict the cellulose solvation ability. A ``working range{''} for IL/DMSO/H2O ratio was observed, tested in cellulose dissolution, and rationalized using cellobiose interaction. Within this solvent ratio, the interactions between components are maximized, being switched on, while out of the range, the interactions are no longer detected. (C) 2021 Elsevier B.V. All rights reserved.}

{Over the past few years porous materials have become a topic of intense research. Porous poly(ionic liquid)s combine the porous architecture with intrinsic ionic liquids properties. In all research areas, the quest for new and improved materials has targeted functional materials with enhanced specificity and efficiency towards the final application. The application of porous materials ranges from sensing, protein separation, solid-phase extraction, catalysis, to CO2 capture and reuse. Recently, the design, synthesis, and porosity control of poly (ionic liquid)s have been attempted through strategies that include classic polymerization techniques as well as molecular imprinting and aerogels production. This review aims at providing the recent advances on porous poly (ionic liquid)s, giving a critical perspective about the works in which key requirements for porosity induction are discussed. Several applications that rely on molecular interactions between the porous material and target compounds are presented, focusing mainly on CO2 capture and reuse, along with some challenges that the scientific community in this field need to be aware of.}

{In the last few years, ionic liquids (ILs) have been the focus of extensive studies concerning the relationship between structure and properties and how this impacts their application. Despite a large number of studies, several topics remain controversial or not fully answered, such as: the existence of ion pairs, the concept of free volume and the effect of water and its implications in the modulation of ILs physicochemical properties. In this paper, we present a critical review of state-of-the-art literature regarding structure-property relationship of ILs, we re-examine analytical theories on the structure-property correlations and present new perspectives based on the existing data. The interrelation between transport properties (viscosity, diffusion, conductivity) of IL structure and free volume are analysed and discussed at a molecular level. In addition, we demonstrate how the analysis of microscopic features (particularly using NMR-derived data) can be used to explain and predict macroscopic properties, reaching new perspectives on the properties and application of ILs.}

The mitigation of climate change effects requires the use of alternative materials and technologies to control CO2 atmospheric levels through its capture, storage and use. In this field, the current work presents the evaluation of two poly(ionic liquid)s (PILs) (poly-1-vinyl-3-ethylimidazolium acetate and hydroxide) combined with free ionic liquid (IL) 1-butyl-3-methylimidolium acetate (BMI·OAc) for CO2 capture. The sorption capacity of PIL@IL composites was evaluated under 20 bar of CO2 at 298 K. Nuclear Magnetic Resonance (NMR) spectroscopy allowed quantification of CO2 sorption (physisorption and/or chemisorption) and in situ study of the PIL−CO2 interaction mechanism. NMR in combination with Molecular Dynamics (MD) simulations suggested a 3D organization of PIL composites, maintaining a similar organization to ILs. Also, the use of aqueous solutions of PIL@IL composites was tested, identifying the optimum conditions for water activation (intrinsic water trapped inside IL structure) for chemisorption. As our main contribution, we demonstrate the possibility to control the sorption pathway towards CO2 physisorption, or CO2 conversion (chemisorption) through carbonation (HCO3−/CO32-) according to the PIL/IL ratio, ions structure and water amount. The use of PIL/IL composites is a promising advance for further CO2 reuse approaching a biomimetic carbonation process.

Ionic liquids (ILs) are among the most studied and promising materials for selective CO2 capture and transformation. The high CO2 sorption capacity associated with the possibility to activate this rather stable molecule through stabilization of ionic/radical species or covalent interactions either with the cation or anion has opened new avenues for CO2 functionalization. However, recent reports have demonstrated that another simpler and plausible pathway is also involved in the sorption/activation of CO2 by ILs associated with basic anions. Bare ILs or IL solutions contain almost invariable significant amounts of water and through interaction with CO2 generate carbonates/bicarbonates rather than carbamic acids or amidates. In these cases, the IL acts as a base and not a nucleophile and yields buffer‐like solutions that can be used to shift the equilibrium toward acid products in different CO2 reutilization reactions. In this Minireview, the emergence of IL buffer‐like solutions as a new reactivity paradigm in CO2 capture and activation is described and analyzed critically, mainly through the evaluation of NMR data.

Among the movements observed in some cellulosic structures produced by plants are those that involve the dispersion and burial of seeds, as for example in Erodium from the Geraniaceae plant family. Here we report on a simple and efficient strategy to isolate and tune cellulose-based hygroscopic responsive materials from Erodium awns' dead tissues. The stimuli-responsive material isolated forms left-handed (L) or right-handed (R) helical birefringent transparent ribbons in the wet state that reversibly change to R helices when the material dries. The humidity-driven motion of dead tissues is most likely due to a composite material made of cellulose networks of fibrils imprinted by the plant at the nanoscale, which reinforces a soft wall polysaccharide matrix. The inversion of the handedness is explained using computational simulations considering filaments that contract and expand asymmetrically. The awns of Erodium are known to present hygroscopic movements, forming R helices in the dry state, but the possibility of actuating chirality via humidity suggests that these cellulose-based skeletons, which do not require complicated lithography and intricate deposition techniques, provide a diverse range of applications from intelligent textiles to micro-machines.

The preorganization and cooperation mechanism of imide‐based ionic liquids reported in a recent Communication was evocated to rationalize the extremely high gravimetric CO2 capture displayed by these fluids. An analysis of the reported spectroscopic evidences together with additional experiments led to the proposition of an alternative, simpler, and feasible mechanism involving the formation of bicarbonate.

Ionic liquids have been on the spotlight of chemical research field in the last decades. Their physical properties (low vapor pressure, thermal stability, and conductivity) and the possibility of fine tuning make them a versatile class of compounds for a wide range of applications, such as catalysis, energy, and material sciences. Ionic liquids can establish multiple intermolecular interactions with solutes such as electrostatic, van der Waals, or hydrogen bonds. The prospect of designing ionic liquid structures toward specific applications has attracted the attention to these alternative solvents. However, their rational design demands a molecular detailed view, and Nuclear Magnetic Resonance is a unique and privileged technique for this purpose, as it provides atomic resolution and at the same time enables the study of dynamic information. In this chapter, we provide an overview about the application of Nuclear Magnetic Resonance spectroscopy techniques as a methodology for the rational design of ionic liquids as solvents for small organic compounds, CO2 capture, and polymers such as cellulose focusing mainly in the last 10 years.

Confined water in aqueous solutions of imidazolium-based ionic liquids (ILs) associated with acetate and imidazolate anions react reversibly with CO2 to yield bicarbonate. Three types of CO2 sorption in these “IL aqueous solutions” were observed: physical, CO2-imidazolium adduct generation, and bicarbonate formation (up to 1.9 molbicarbonate mol−1 of IL), resulting in a 10:1 (molar ratio) total absorption of CO2 relative to imidazolate anions in the presence of water 1:1000 (IL/water). These sorption values are higher than the classical alkanol amines or even alkaline aqueous solutions under similar experimental conditions.