How do arenediazonium salts behave in deep eutectic solvents? A combined experimental and computational approach

Binary Mixtures of Choline Acetate and Tetrabutylammonium Acetate with Natural Organic Acids by Vibrational Spectroscopy and Molecular Dynamics Simulations

We present a study of several mixtures obtained by the mixing of two organic acetate-based salts (choline acetate, ChAc, or tetrabutylammonium acetate, TBAAc) with three different natural organic acids (ascorbic acid, AA, citric acid, CA, and maleic acid, MA). The structures of the starting materials and of the mixtures were characterized by infrared spectroscopy (FT-IR) and classic molecular dynamics simulations (MD). The thermal behavior was characterized by differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The obtained mixtures, especially the ChAc-based ones, strongly tend to vitrify at low temperatures and are stable up to 100-150 °C. The FTIR measurements suggest the formation of a strong H-bond network: the coordination between acids and ChAc or TBAAc takes place by the donation of the H-bond by the acids to the oxygen of the acetate anion, which acts as an acceptor (HBA). The comparison with MD analysis indicates that acids predominantly exploit their more acidic hydrogens. In particular, we observe the progressive shift of νC═O and νOH when the ratios of acids increase. The structural differences between the two studied cations influence the spatial distribution of the components in the mixture bulk phases. In particular, the analysis of the theoretical structure function I(q) of the TBAAc-based systems shows the presence of important prepeaks at low q, a sign of the formation of apolar domain, due to the nanosegregation of the alkyl chains.

Design of a New Chiral Deep Eutectic Solvent Based on 3-Amino-1,2-propanediol and Its Application in Organolithium Chemistry

A chiral glycerol derivative, namely 3-amino-1,2-propanediol, was employed for as the hydrogen bond donor (HBD) in the design of a new deep eutectic solvent (DES) with choline chloride acting as the hydrogen bond acceptor (HBA). The novel mixture was characterized and unambiguously classified as a DES. Furthermore, its synthetic usefulness was demonstrated in the room-temperature n-butyllithium-addition under air to carbonyl compounds and benzyl chloride. In some cases, pure products (100% conversion) were obtained by a simple extractive work-up in up to 72% isolated yield, thus suggesting the potential practical usefulness of this procedure as a green alternative to the classical Schenk procedure in volatile organic solvents for the synthesis of tertiary alcohols. The chirality of the HBD, bearing an interesting basic primary amino group, is an intriguing feature currently under investigation for further exploitation.

C-N, C-O and C-S Ullmann-Type Coupling Reactions of Arenediazonium o-Benzenedisulfonimides

Arenediazonium o-benzenedisulfonimides have been used as efficient electrophilic partners in Cu(I) catalysed Ullmann-type coupling. The synthetic protocols are mild and easy, and produced either N-alkylanilines, aryl ethers, or thioethers in fairly good yields (18 positive examples, average yield 66%). o-Benzenedisulfonimide was recovered at the end of the reactions and was reused to prepare the starting salts for further reactions. It is noteworthy that diazonium salts have been used as electrophilic partners in the Ullmann-type protocol for the first time.

Recent Advances in the Synthesis of Inorganic Materials Using Environmentally Friendly Media

Deep Eutectic Solvents have gained a lot of attention in the last few years because of their vast applicability in a large number of technological processes, the simplicity of their preparation and their high biocompatibility and harmlessness. One of the fields where DES prove to be particularly valuable is the synthesis and modification of inorganic materials-in particular, nanoparticles. In this field, the inherent structural inhomogeneity of DES results in a marked templating effect, which has led to an increasing number of studies focusing on exploiting these new reaction media to prepare nanomaterials. This review aims to provide a summary of the numerous and most recent achievements made in this area, reporting several examples of the newest mixtures obtained by mixing molecules originating from natural feedstocks, as well as linking them to the more consolidated methods that use "classical" DES, such as reline.

Copper-Free Halodediazoniation of Arenediazonium Tetrafluoroborates in Deep Eutectic Solvents-like Mixtures

Deep Eutectic Solvent (DES)-like mixtures, based on glycerol and different halide organic and inorganic salts, are successfully exploited as new media in copper-free halodediazoniation of arenediazonium salts. The reactions are carried out in absence of metal-based catalysts, at room temperature and in a short time. Pure target products are obtained without the need for chromatographic separation. The solvents are fully characterized, and a computational study is presented aiming to understand the reaction mechanism.

Ullmann homocoupling of arenediazonium salts in a deep eutectic solvent. Synthetic and mechanistic aspects

DES is exploited as a solvent media in Ullmann homocoupling of arenediazonium salts. Computational study supported by Raman spectroscopy is presented, aiming to elucidate the reaction mechanism.