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We report the synthesis and characterization of four similar chiral 1-methyl-1H-imidazole π-conjugated derivatives. In particular, we focus on the thin film chiroptical characterization (electronic circular dichroism and circular polarized luminescence), able to highlight how small changes in the chemical structure can lead to significant variations in the solid state aggregation. For one material showing relevant circularly polarized luminescence (CPL) properties, we have been able to detect the signal with the aid of an ultra-cheap setup we designed, which in this case showed good performance in comparison to our standard CPL instrument. We demonstrated that this setup can detect CPL signals with elevated dissymmetry factor in spite of its highly reduced complexity and much lower cost if compared to conventional CPL instrumentations. [ABSTRACT FROM AUTHOR]

The possibilities offered by organic fluorophores in the preparation of advanced plastic materials have been increased by designing novel alkynylimidazole dyes, featuring different push and pull groups. This new family of fluorescent dyes was synthesized by means of a one-pot sequential bromination–alkynylation of the heteroaromatic core, and their optical properties were investigated in tetrahydrofuran and in poly(methyl methacrylate). An efficient in silico pre-screening scheme was devised as consisting of a step-by-step procedure employing computational methodologies by simulation of electronic spectra within simple vertical energy and more sophisticated vibronic approaches. Such an approach was also extended to efficiently simulate one-photon absorption and emission spectra of the dyes in the polymer environment for their potential application in luminescent solar concentrators. Besides the specific applications of this novel material, the integration of computational and experimental techniques reported here provides an efficient protocol that can be applied to make a selection among similar dye candidates, which constitute the essential responsive part of those fluorescent plastic materials. [ABSTRACT FROM AUTHOR]

A series of new ionic liquids (ILs) based on trialkylglycerylphosphonium cations have been prepared starting from 3-chloropropane-1,2-diol or (2,2-dimethyl-1,3-dioxolan-4-yl)methanol, two compounds readily obtainable from glycerol (a widely available and cheap waste product). All the new phosphonium salts were characterized by NMR, IR and DSC, and their efficacy as polar additives in a typical base-promoted Baylis–Hillman reaction was also evaluated. [ABSTRACT FROM AUTHOR]

Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC-H) and its lithium salt (AC-Li) in chiral ionic liquid (CIL), (R)-1-(2,3-dihydroxypropyl)-3-methylimidazolium acetate {[(R)-GLYMI][AcO]}, gave a mixture of two head-to-tail (HT) and two head-to-head (HH) cyclodimers in HT/HH ratios of 1.3-1.7 (for AC-H) and 2.2-4.3 (for AC-Li) with low enantiomeric excesses (ee) of 0-3% for chiral syn-HT and anti-HH dimers. In contrast, irradiation of AC-H in an aqueous solution, containing cucurbit[8]uril (CB[8]) as a host and [(R)-GLYMI][AcO] or [(R)-GLYMI][Tf(2)N] as a modifier of CB portals, afforded the HH dimers in 91-99% selectivity, although the anti-HH dimer was totally racemic. Interestingly, irradiation of AC-H in a dichloromethane solution, containing [(R)-GLYMI][AcO] as a chiral template, led to the formation of the HH-dimers in 98% selectivity with chiral anti-HH dimer in -14% ee, presumably by the dual ligation of two ACs to a CIL through electrostatic and hydrogen-bonding interactions.