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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]

Four families of structurally related chiral π‐conjugated oligomers bearing a hydroquinone (HQ), 1,5‐dihydroxynaphthalene (Naph), benzo[1,2‐b:4,5‐b']dithiophene‐4,8‐diol (BDT) or 9H‐carbazole (CBZ) central core, for a total of 11 new compounds, have been synthesized by simple and versatile synthetic strategies involving Pd‐catalyzed cross‐coupling protocols: a Suzuki‐Miyaura reaction, a Sonogashira/desilylation/Sonogashira sequence or a Sonogashira/desilylation/acyl Sonogashira sequence. A systematic investigation of the optical and chiroptical features of the final chiral dyes was performed in chloroform solution and on spin‐coated thin films. The ECD investigation was crucial in revealing that, even within the same family of organic dyes, minor variations in the nature and length of the π‐conjugated backbone can result in very different solid‐state arrangements at different hierarchical scales. [ABSTRACT FROM AUTHOR]

Chiral materials formed by aggregated organic compounds play a fundamental role in chiral optoelectronics, photonics and spintronics. Nonetheless, a precise understanding of the molecular interactions involved remains an open problem. Here we introduce magnetic circular dichroism (MCD) as a new tool to elucidate molecular interactions and structural parameters of a supramolecular system. A detailed analysis of MCD together with electronic circular dichroism spectra combined to ab initio calculations unveils essential information on the geometry and energy levels of a self‐assembled thin film made of a carbazole di‐bithiophene chiral molecule. This approach can be extended to a generality of chiral organic materials and can help rationalizing the fundamental interactions leading to supramolecular order. This in turn could enable a better understanding of structure–property relationships, resulting in a more efficient material design. [ABSTRACT FROM AUTHOR]

Three diketopyrrolo[3,4- I c i ]pyrrole-1,2,3-1 I H i -triazole (DPP) dyes bearing the same chiral appendage R* but decorated with different achiral substituent groups Y showed profoundly different optical, chiroptical, electrochemical and thermal features in their aggregated form. Keywords: chirality; diketopyrrolopyrroles; organic dyes; supramolecular chemistry; triazoles EN chirality diketopyrrolopyrroles organic dyes supramolecular chemistry triazoles 1 1 1 06/21/23 20230619 NES 230619 B Supramolecular chirality b is far from being determined only by local stereogenic elements. Chirality, diketopyrrolopyrroles, organic dyes, supramolecular chemistry, triazoles. [Extracted from the article]

Instrumental techniques able to identify and structurally characterize the aggregation states in thin films of chiral organic π-conjugated materials, from the first-order supramolecular arrangement up to the microscopic and mesoscopic scale, are very helpful for clarifying structure-property relationships. Chiroptical imaging is currently gaining a central role, for its ability of mapping local supramolecular structures in thin films. The present review gives an overview of electronic circular dichroism imaging (ECDi), circularly polarized luminescence imaging (CPLi), and vibrational circular dichroism imaging (VCDi), with a focus on their applications on thin films of chiral organic dyes as case studies., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Invited for the cover of this issue are the research groups of Lorenzo Di Bari at the University of Pisa and Gianluca Maria Farinola at the University of Bari Aldo Moro. The image depicts three diketopyrrolo[3,4-c]pyrrole-1,2,3-1H-triazole dyes with the same chiral appendage R* but different achiral substituent groups Y showing profoundly different features in their aggregated form. Read the full text of the article at 10.1002/chem.202300291., (© 2023 Wiley-VCH GmbH.)