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A panel of dicationic ionic liquids (DILs) with different rigid xylyl (ortho, meta, para) spacers and different anions (bromide and tungstate) has been synthetised and characterised through different experimental and computational techniques. Differences and analogies between the systems are analysed using information derived from their DFT structures, semiempirical dynamics, thermal behaviour, and catalytic properties versus the well-known reaction of CO2 added to epichlorohydrin. A comparison between the proposed systems and some analogues that present non-rigid spacers shows the key effect displayed by structure rigidity on their characteristics. The results show an interesting correlation between structure, flexibility, properties, and catalytic activity. [ABSTRACT FROM AUTHOR]

A panel of novel vanadium(IV)–betaine complexes has been synthesized according to new and efficient methodologies and characterized through both spectroscopic techniques and thermal analyses. Vanadium(IV)–betaine solutions have been electrochemically oxidized and the effect of betaine ligands on the thermal and pH stability of vanadium(V) solutions has been evaluated under different temperature and acidity conditions. The obtained results displayed a remarkable effect for both of the examined parameters, achieving the preparation of aqueous vanadium(V) solutions displaying long term stability at more than 55 °C under mild acidic conditions. The species formed in the betaine rich vanadium(V) solutions have been sprectroscopically identified in relationship with the acidity of the solution, and the obtained results were confirmed through computational techniques. Vanadium–betaine based solutions have been finally tested in a lab-scale redox flow battery setup, providing preliminary insight into the possible use of this type of electrolyte in VRFBs. [ABSTRACT FROM AUTHOR]

An efficient synthesis of symmetrical 1,2-disubstituted 4,5- dialkynylimidazoles by Sonogashira alkynylation of the corresponding 4,5-dibromo derivatives was developed. Moreover, through a careful tuning of the palladium ligand, unsymmetrical 1,2-disusbtituted 4,5-dialkynylimidazoles were also prepared through a regioselective C5 alkynylation of 4,5-dibromoimidazoles, followed by a second alkynylation involving the 4-bromo derivatives so obtained. This interesting class of imidazole-fused enediynes is also able to give thermal Bergman cycloaromatization (BC), as proved by DSC experiments. [ABSTRACT FROM AUTHOR]