Two molecular copper­(II) complexes, (NMe4)2[CuII(L1)] (1) and (NMe4)2[CuII(L2)] (2), ligated by a N2O2 donor set of ligands [L1 = N,N′-(1,2-phenylene)­bis­(2-hydroxy-2-methylpropanamide), and L2 = N,N′-(4,5-dimethyl-1,2-phenylene)­bis­(2-hydroxy-2-methylpropanamide)] have been synthesized and thoroughly characterized. An electrochemical study of 1 in a carbonate buffer at pH 9.2 revealed a reversible copper-centered redox couple at 0.51 V, followed by two ligand-based oxidation events at 1.02 and 1.25 V, and catalytic water oxidation at an onset potential of 1.28 V (overpotential of 580 mV). The electron-rich nature of the ligand likely supports access to high-valent copper species on the CV time scale. The results of the theoretical electronic structure investigation were quite consistent with the observed stepwise ligand-centered oxidation process. A constant potential electrolysis experiment with 1 reveals a catalytic current density of >2.4 mA cm–2 for 3 h. A one-electron-oxidized species of 1, (NMe4)­[CuIII(L1)] (3), was isolated and characterized. Complex 2, on the contrary, revealed copper and ligand oxidation peaks at 0.505, 0.90, and 1.06 V, followed by an onset water oxidation (WO) at 1.26 V (overpotential of 560 mV). The findings show that the ligand-based oxidation reactions strongly depend upon the ligand’s electronic substitution; however, such effects on the copper-centered redox couple and catalytic WO are minimal. The energetically favorable mechanism has been established through the theoretical calculation of stepwise reaction energies, which nicely explains the experimentally observed electron transfer events. Furthermore, as revealed by the theoretical calculations, the O–O bond formation process occurs through a water nucleophilic attack mechanism with an easily accessible reaction barrier. This study demonstrates the importance of redox-active ligands in the development of molecular late-transition-metal electrocatalysts for WO reactions.

A terminal FeIIIOH complex, [FeIII(L)(OH]2– (1), has been synthesized and structurally characterized (H4L = 1,2-bis(2-hydroxy-2-methylpropanamido)benzene). The oxidation reaction of 1 with one equiv. of tris(4-bromophenyl)ammoniumyl hexachloroantimonate (TBAH) or ceric ammonium...

In this work jute fiber has been treated with Maleic Anhydride grafted PP (MAgPP) and also Vinyl trimethoxy silane (VTMO) at various concentration levels and the tensile, interfacial, and moisture regain properties of the composites are studied in detail. Tensile and flexural tests are carried out to characterize the mechanical properties and fiber pull out test is carried out to characterize the interfacial properties. It has been found that both MAgPP and VTMO treatments improve the tensile properties of the resultant composites. MAgPP treatment yields higher increase in composite tensile properties. Fiber pull out tests also indicate better interfacial strength for MAgPP treated fibers. The influence of fiber volume fraction on tensile and flexural properties is carried out for composites with MAgPP treated jute fibers.

Stretch fabrics are used in manufacturing pressure garments (PG) to exert pressure over specific body parts in medical conditions like venous and lymphatic disorders, scar management, and bone and muscle injuries. The amount of therapeutic pressure required in each medical condition is different; therefore, there is a need to engineer the stretch properties of garments to match the requirements in each case. Limited information is available on the relationship between fabric properties and the pressure generated on the body. In this paper, an attempt has been made to study the effect of inlay yarn pre-tension at the time of manufacturing of stretch fabrics on the pressure generated by the garments. Results show that change in inlay pre-tension significantly changes the structural characteristics of the fabric but the load elongation behavior remains unchanged up to 100% extension. Pressure exerted on rigid cylindrical tubes increases with reduction factor of the fabric tube and the curvature of the cylinder.

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