Toward Pore Size-Selective Photoredox Catalysis Using Bifunctional Microporous 2D Triazine-Based Covalent Organic Frameworks.

The design and synthesis of photoactive metal-free 2D materials for selective heterogeneous photoredox catalysis continue to be challenging due to issues related to nonrecyclability, and limited photo- and chemical stability. Herein, we report the photocatalytic properties of a triazine-based porous COF, , which is found to be capable of facilitating both SET (single electron transfer) for photocatalytic reductive debromination of phenacyl bromide in absence of oxygen and generation of reactive oxygen species (ROS) for benzylamine photo-oxidation in the presence of oxygen, respectively, under visible light irradiation. Inspired by the latter results, we further systematically investigated different-sized benzylamine substrates in this single-component reaction and compared the results with an analogous COF () exhibiting a larger pore size.

Emissive Substoichiometric Covalent Organic Frameworks for Water Sensing and Harvesting.

Emissive covalent organic frameworks (COFs) have recently emerged as next-generation porous materials with attractive properties such as tunable topology, porosity, and inherent photoluminescence. Among the different types of COFs, substoichiometric frameworks (so-called Type III COFs) are especially attractive due to the possibility of not only generating unusual topology and complex pore architectures but also facilitating the introduction of well-defined functional groups at precise locations for desired functions. Herein, the first example of a highly emissive (PLQY 6.

A covalent organic polymer as an efficient chemosensor for highly selective HS detection through proton conduction.

A hydrazide based covalent organic polymer (COP) with pyridine functionalities has been synthesized and used to fabricate an efficient chemosensor for the detection of gaseous HS at 25 °C through a proton conduction process. The gas sensing behavior of the COP has been measured in a dynamic flow-through resistance measurement system. The COP fabricated sensor shows a lower response time of 9 s with a recovery time of 12 s, when the experiment is performed with a HS concentration of 200 ppm at 25 °C.

Benzoselenadiazole-Based Conjugated Molecules: Active Switching Layers with Nanofibrous Morphology for Nonvolatile Organic Resistive Memory Devices.

In this work, two symmetrical donor-acceptor-donor (D-A-D) type benzoselenadiazole (BSeD)-based π-conjugated molecules were synthesized and employed as an active switching layer for non-volatile data storage applications. BSeD-based derivatives with different donor units attached through common vinylene linkers showed different electrical and optical properties. 4,7-Di((E)-styryl)benzo[c][2,1,3]selenadiazole (DSBSeD) and 4,7-bis((E)-4-methoxystyryl)benzo[c][2,1,3]selenadiazole (DMBSeD) are sandwiched between gallium-doped ZnO (GZO) and metal aluminum electrodes respectively through solution-processed spin-coating method.

Insights into the Aggregation Behaviour of a Benzoselenadiazole-Based Compound and Generation of White Light Emission.

We have designed and synthesized the benzoselenadiazole (BDS) based donor-acceptor-donor (D-A-D) π-conjugated compound 4,7-di((E)styryl)benzo[2,1,3]selenadiazole (1). A single-crystal study of 1 shows J-type molecular aggregation in the solid state. The crystal packing of 1 shows head-to-head dimeric intermolecular assembly via Se⋅⋅⋅N interactions while staircase-type interlock molecular packing has occurred via Se⋅⋅⋅π interaction.

Redox-Active Dynamic Self-Supporting Thixotropic 3D-Printable G-Quadruplex Hydrogels.

Redox-active G-quadruplex hydrogels were prepared by dynamic boronate ester formation between ferroceneboronic acid and guanosine. Dynamic boronate esters imparted thixotropic and 3D-printability to the hydrogel. Initially, the ferrocene moiety was oxidised to produce a weaker ferrocenium-based green hydrogel.

Understanding the conformational analysis of gababutin based hybrid peptides.

Constrained γ-amino acid gababutin (Gbn) based peptides that form different conformations have been synthesized. Striving to rationalize the impact of side chain orientations framing tetrapeptide-based supramolecular organic frameworks and morphological entities, Gbn incorporated hybrid peptides Boc-Gbn-Aib-Aaa-Aib-OMe (where Aaa = Phe(F) for peptide 1, Leu(L) for peptide 2 and Tyr(Y) for peptide 3) were synthesized by changing the amino acid at the third position. The solution state dual folded conformation (C/C H-bonded) is probed by 2D NMR spectroscopy in support of a DMSO-d titration and VT NMR experiments.

Redox-Active Peptide-Functionalized Quinquethiophene-Based Electrochromic π-Gel.

An electrochromic system based on a self-assembled dipeptide-appended redox-active quinquethiophene π-gel is reported. The designed peptide-quinquethiophene consists of a symmetric bolaamphiphile that has two segments: a redox-active π-conjugated quinquethiophene core for electrochromism, and peptide motif for the involvement of molecular self-assembly. Investigations reveal that self-assembly and electrochromic properties of the π-gel are strongly dependent on the relative orientation of peptidic and quinquethiophene scaffolds in the self-assembly system.