A hydrazide based covalent organic polymer (COP) having pyridine functionalities has been synthesized and used to fabricate an efficient chemosensor for the detection of gaseous H2S at 25 °C through...

Two dimensional covalent organic frameworks (2D COFs) are unique class of crystalline porous polymers which are formed by the covalent bonding between the organic building blocks. Their layers are stacked to each other by non-covalent interactions. The stacking sequence between the layers is highly significant towards various applications. In this article, we have prepared ruthenium ions encapsulated 2D COF (Ru@COF) from a synthesized COF. We have performed an electrochemical hydrogen evolution reaction using Ru@COF as electrocatalyst. Moreover, Ru@COF shows better electrochemical hydrogen evolution reaction (HER) activity compared to bare RuCl 3 and COF. The HER activities are measured in 1.5 M H 2 SO 4 medium. Ru@COF shows onset potential 159 mV with the Tafel slope of 79 mV dec À 1 . The linear Tafel plot with the slope 79 mV dec À 1 indicates Volmer-Heyrovsky-Tafel mechanism for the Ru@COF catalysed HER. COF plays a crucial role in maintaining stability and catalytic efficiency of the material. Interestingly, Ru@COF acts as exemplary electrocatalyst material that is used as solid binder-free cathodic electrode on glassy carbon electrode surface.

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 6.8%) substoichiometric 2D-COF (COF-SMU-1) featuring free uncondensed aldehyde groups is reported. In particular, COF-SMU-1 features a dual-pore architecture with an overall bex net topology, tunable emission in various organic solvents, and distinct colorimetric changes in the presence of water. To gain further insights into its photoluminescence properties, the charge transfer, excimer emission, and excited state exciton dynamics of COF-SMU-1 are investigated using femtosecond transient absorption spectroscopy in different organic solvents. Additionally, highly enhanced atmospheric water-harvesting properties of COF-SMU-1 are revealed using FT-IR and water sorption studies.The findings will not only lead to in-depth understanding of structure-property relationships in emissive COFs but also open new opportunities for designing COFs for potential applications in solid-state lighting and water harvesting.

Redox-activeG -quadruplex hydrogels were prepared by dynamic boronate ester formation between ferroceneboronic acid and guanosine. Dynamic boronate esters imparted thixotropic and 3D-printabilityt ot he hydrogel. Initially,t he ferrocene moiety was oxidised to produce a weakerf errocenium-basedg reen hydrogel. However,t he less stable ferrocenium converted into more stable ferrocene to produce ah ydrophobic,w ater-stablea nd robust hydrogel.