Anion Recognition and the Templated Solid-State Synthesis of Hemicucurbiturils. Hemikukurbituriilid kui anioonide retseptorid ning nende mehhanokeemiline s\ufcntees tahkes faasis

Doctoral thesis 6/2019 Doktorit\uf6\uf6 6/201

Selective Capture of Small Environmental Pollutants by Cyclohexanohemicucurbit[<i>n</i>]urils

Persistent organic pollutants that occur in different environmental matrices create a need for their sensing, removal and remediation [...

A Greener Route to Blue: Solid-State Synthesis of Phthalocyanines

| openaire: EC/H2020/101027061/EU//ENBIOMECHPhthalocyanines are important organic dyes with a broad applicability in optoelectronics, catalysis, sensing and nanomedicine. Currently, phthalocyanines are synthetized in high boiling organic solvents, like dimethylaminoethanol (DMAE), which is a flammable, corrosive, and bioactive substance, miscible with water and harmful to the environment. Here we show a new solid-state approach for the high-yielding synthesis of phthalocyanines, which reduces up to 100-fold the amount of DMAE. Through systematic screening of solid-state reaction parameters, carried out by ball-milling and aging, we reveal the influence of key variables—temperature, presence of a template, and the amount and role of DMAE in the conversion of tBu phthalonitrile to tetra-tBu phthalocyanine. These results set the foundations to synthesize these high-performance dyes through a greener approach, opening the field of solid-state synthesis to a wider family of phthalocyanines.Peer reviewe

Size-Control by Anion Templating in Mechanochemical Synthesis of Hemicucurbiturils in the Solid State

Self-organization is one of the most intriguing phenomena of chemical matter. While the self-assembly of macrocycles and cages in dilute solution has been extensively studied, it remains poorly understood in solvent-free environments. Here, we provide the first example of using anionic templates to achieve selective assembly of differently sized macrocycles in a solvent-free system. Using the acid-catalyzed synthesis of cyclohexanohemicucurbiturils as a model system, we demonstrate size-controlled quantitative synthesis of 6- or 8-membered macrocycles, taking place through spontaneous anion-directed re-organization of mechanochemically-obtained oligomers in the solid state.<br /

Dynamic Chiral Cyclohexanohemicucurbit[12]uril

This research with title "Dynamic chiral cyclohexanohemicucurbit[12]uril" is dedicated to the memory of late Professor Hans J. Reich.Abstract:NMR and DFT studies of chiral cyclohexanohemicucurbit[12]uril indicate that the macrocycle adopts a concave octagon shape with three distinct ranges of conformational flexibility in solution. Methylene bridge flipping occurs at temperatures above 265 K, while urea monomers rotate at temperatures above 308 K resulting in the loss of confined space within the macrocycle

Cyclohexanohemicucurbit[8]uril forms inclusion complexes with heterocycles and removes sulfuric guests from water via solid-phase extraction

We found that cyclohexanohemicucurbit[8]uril encapsulates five- and six-membered sulfur- and oxygen-containing unsubstituted heterocycles and can be used as a selective sorption material for the extraction of sulfur-heterocycles like 1,3-dithiolane and α‑lipoic acid from water

CaCl₂, Bisoxazoline, and Malonate: A Protocol for an Asymmetric Michael Reaction

A mild protocol for the asymmetric Michael addition of dimethyl malonate to various α,β-unsaturated carbonyl compounds was developed. The salient feature of this methodology is that a cheap and environmentally friendly Lewis acid, CaCl₂, was used as a catalyst. An aminoindanol- and pyridine-derived ligand provided in the presence of CaCl₂ Michael adducts in moderate to high enantioselectivities. The scope of the reaction was demonstrated