Herein, a novel and versatile method for the synthesis of N-heteroarylated dithieno[3,2-b:2,3′-d]pyrroles (DTPs) is reported. By microwave-assisted Cu-catalyzed coupling of parent H-DTP 1 with 5- and 6-membered heteroaromatic halides, a variety of novel N-functionalized DTPs were obtained. Supported by quantum chemical calculations and X-ray structure analysis, structural and optoelectronic properties of the π-conjugated systems were investigated and led to valuable structure–property relationships. Selected derivatives were electropolymerized to corresponding conducting DTP polymers.

The first synthesis of organic Tri 6 Di 9 cages is presented. Two structurally distinct Tri 6 Di 9 cages were synthesised by combining a highly fluorinated aldehyde with two ditopic amines. Although the pure compounds could not be isolated despite many attempts, the information obtained is critical for the future design of large supramolecular structures. Computational and experimental methods indicate that the addition of perfluorinated aromatic linkers in the assembly of porous organic cages opens up new possibilities for influencing the reaction pathway towards rare and unknown structures.

Crystal engineering has served as a powerful strategy to grow organic molecular crystals with different physical behaviors and this strategy has been also attempted for a purpose to grow crystals with desired mechanical properties; however, it is quite challenging to endow all different crystal phases constructed by the same compound with unique reversible deformation, such as elastic bending. We herein report a rare example of all-polymorph elastic crystals accompanied by precisely tunable emission colors. Single-crystal structure analyses and their optical and mechanical properties have been fully investigated on all polymorphs. The color-tunable amplified spontaneous emissions of both the straight and elastically bent polymorphs demonstrate the applicability of these elastic polymorphs in future wearable optoelectronic devices.

The temperature-dependent dual fluorescence from a single component of small organic molecules (SOMs) is very promising for the ratiometric fluorescence sensing of temperature. However, the SOM-based fluorophores typically only show one fluorescence band. It is thus very challenging to achieve dual fluorescence, let alone the dual fluorescence that is sensitive to temperature. Herein, in this short review, we briefly summarized the examples of SOM-based fluorophores exhibiting temperature-dependent dual fluorescence. Through representative examples, we mainly focus on the illustration of the intrinsic mechanisms of this unusual phenomenon, which may take place because of the presence of two local minimum conformations that are thermally equilibrated in the ground state, the presence of two local minimum conformations in the first excited state as the result of significant structural relaxation upon excitation, or the presence of thermal equilibrium between the first and second excited states. Hopefully, the discussions in this short review will provide some important guidelines for the further rational molecular design of such fluorophores.

Bottom-up approaches are one strategy geared towards designing novel two-dimensional materials. Supramolecular polymerization has proven to be an effective way of obtaining these architectures due to the increasing control and tunability offered by different functional groups, which are not afforded by conventional polymerization. In this short review, we highlight examples of supramolecular assemblies held together by well-known non-covalent interactions, as well as new approaches that are becoming more relevant in recent years.

Naphthalene-diimide (NDI)-derived building blocks have been explored extensively for supramolecular assembly as they exhibit attractive photophysical properties, suitable for applications in organic optoelectronics. Core-substituted derivatives of the NDI chromophore (cNDI) differ significantly from the parent NDI dye in terms of optical and redox properties. Adequate molecular engineering opportunities and substitution-dependent tunable optoelectronic properties make cNDI derivatives highly promising candidates for supramolecular assembly and functional materials. This short review discusses recent development in the area of functional supramolecular assemblies based on cNDIs and related molecules.Table of contents1. Introduction2. General Supramolecular Assemblies of cNDI Derivatives3. cNDI-Based Chiral Supramolecular Assemblies and Functional Materials4. Controlled Supramolecular Polymerization with cNDI Derivatives5. Dimeric Naphthalimide-Based Building Blocks6. Conclusions and Outlook

Supramolecular chirogenesis represents an effective way to induce chirality at the supramolecular level. For the previous host–guest chirogenic systems, metal–ligand coordination, hydrogen bonding, π–π stacking and hydrophobic interactions have been mainly employed as the non-covalent driving forces. In this study, Pt(II)···Pt(II) metal–metal interactions have been engineered to induce supramolecular chirogenesis, by forming non-covalent clipping structures between chiral platinum receptors and achiral platinum guests together. This results in the emergence of Cotton effects in the metal–metal-to-ligand charge transfer region, ascribed to chirality transfer from trans-1,2-diamide cyclohexane unit on chiral receptors to Pt(II)---Pt(II) non-covalent interacting sites. Supramolecular chirogenesis can be further transferred from organic to aqueous solutions, with higher resistance to concentration and temperature variations in the latter medium. Overall, the current study provides new avenues toward supramolecular chirality systems with tailored properties.

A series of phenyl end-capped α-oligothiophenes containing four to seven thiophene subunits (4T–7T) was synthesized utilizing palladium-catalyzed cross-coupling reactions. UV/Vis spectroscopic analysis revealed one broad absorption band that shifts bathochromically with increasing number of thiophene units. Structured emission spectra are observed with Stokes shift ν~4000 cm−1 and quantum yields of up to 53%. End-capping of the oligothiophene molecules by phenyl units does not only extend the effective conjugation but also prevents from α–α-homocoupling upon electrochemical oxidation. Accordingly, reversible redox waves are observed in cyclic voltammetry with up to four reversible one-electron processes for the two longer congeners. Analyses of the first two oxidation processes in the framework of multiredox systems provide insight into the stabilization or destabilization of polaronic and bipolaronic states. An unusual zig-zag trend for the first (and to a lesser extend second) oxidation process could be explained by the sterical encumbrance of solubilizing hexyl chains in 5T and 7T molecules which counteract the formation of a fully planar quinoidal oligothiophene backbone.

Oligo(p-phenylene)s with a donor phenol group and an acceptor pyridinium moiety separated by one and two p-phenylene units were synthesized by the linear iterative Suzuki–Miyaura coupling method using aryl nonaflates as effective coupling reagents. Zwitterionic forms of these push–pull molecules were generated upon deprotonation of the phenol leading to large redshifts in absorbance maxima. UV-vis absorbance studies also revealed strong dependence of the band position on solvent polarity: a smooth bathochromic shift can be observed with the decrease of the solvent polarity. The molecule with one p-phenylene bridging unit showed the strongest solvatochromic characteristics in the series, spanning the range of 167 nm while moving from polar water to less polar N,N-dimethylformamide. The magnitude of this shift was close to Reichardt's dye — one of the most solvatochromic organic dyes known.

Peptidic sequences when conjugated to π-electronic groups form self-assembled networks of π-electron pathways. These materials hold promise for bio-interfacing charge transporting applications because of their aqueous processability and compatibility. In this work, we incorporated diketopyrrolopyrrole (DPP), a well-established π-core for organic electronic applications, within the peptidic sequence. We embedded different numbers of thiophene rings (2 and 3) on both sides of the DPP to alter the length of the π-cores. We also varied the length of the N-alkyl side chains (methyl, butyl, hexyl) attached to the DPP core. These variations allowed us to explicitly study the effect of π-core and N-alkyl side-chain length on photophysical properties and morphology of the resulting nanomaterials. All of these molecules formed H-type aggregates in the assembled state. Longer π-cores have relatively red-shifted absorption maxima, whereas the N-alkyl variation did not present significant photophysical changes.