Polypyrrole with Phosphor Tungsten Acid and Carbide-Derived Carbon: Change of Solvent in Electropolymerization and Linear Actuation.

Linear actuators based on polypyrrole (PPy) are envisaged to have only one ion that triggers the actuation direction, either at oxidation (anion-driven) or at reduction (cation-driven). PPy doped with dodecylbenzenesulfonate (PPy/DBS) is the most common applied conducting polymer having cation-driven actuation in aqueous solvent and mainly anion-driven actuation in an organic electrolyte. It is somehow desired to have an actuator that is independent of the applied solvent in the same actuation direction. In this research we made PPy/DBS with the addition of phosphorus tungsten acid, forming PPyPT films, as well with included carbide derived carbon (CDC) resulting in PPyCDC films. The solvent in electropolymerization was changed from an aqueous ethylene glycol mixture to pure EG forming PPyPT-EG and PPyCDC-EG composites. Our goal in this study was to investigate the linear actuation properties of PPy composites applying sodium perchlorate in aqueous (NaClO4-aq) and propylene carbonate (NaClO4-PC) electrolytes. Cyclic voltammetry and square potential steps in combination with electro-chemo-mechanical-deformation (ECMD) measurements of PPy composite films were performed. The PPyPT and PPyCDC had mixed ion-actuation in NaClO4-PC while in NaClO4-aq expansion at reduction (cation-driven) was observed. Those novel PPy composites electropolymerized in EG solvent showed independently which solvent applied mainly expansion at reduction (cation-driven actuator). Chronopotentiometric measurements were performed on all composites, revealing excellent specific capacitance up to 190 F g-1 for PPyCDC-EG (best capacitance retention of 90 % after 1000 cycles) and 130 F g-1 for PPyPT-EG in aqueous electrolyte. The films were characterized by scanning electron microscopy (SEM), Raman, Fourier-transform infrared (FTIR) and energy dispersive X-ray spectroscopy (EDX).

An efficient access to ß-ketosulfones via ß-sulfonylvinylamines: metal-organic framework catalysis for the direct C-S coupling of sodium sulfinates with oxime acetates.

A copper-based framework Cu2(OBA)2(BPY) was synthesized and used as a recyclable heterogeneous catalyst for the synthesis of ß-sulfonylvinylamines from sodium sulfinates and oxime acetates via direct C-S coupling reaction. The transformation was remarkably affected by the solvent, and chlorobenzene emerged as the best option. This Cu-MOF displayed higher activity than numerous conventional homogeneous and MOF-based catalysts. The catalyst was reutilized many times in the synthesis of ß-sulfonylvinylamines without considerably deteriorating in catalytic efficiency. These ß-sulfonylvinylamines were readily converted to the corresponding ß-ketosulfones via a hydrolysis step with aqueous HCl solution. To the best of our knowledge, this direct C-S coupling reaction to achieve ß-sulfonylvinylamines was not previously conducted with a heterogeneous catalyst.

Auxiliary-directed etherification of sp2 C-H bonds under heterogeneous metal-organic framework catalysis: synthesis of ethenzamide.

An efficient protocol for 8-aminoquinoline assisted alkoxylation and phenoxylation of sp2 C-H bonds under heterogeneous catalysis was developed. The optimal conditions employed Cu-MOF-74 (20%), K2CO3 base, pyridine ligand or dimethyl formamide solvent, and O2 oxidant at 80 °C or 100 °C for 24 hours. Cu-MOF-74 revealed remarkably higher activity when compared with other previously commonly used Cu-MOFs in cross coupling reactions, supported copper catalysts, and homogeneous copper salts. The reaction scope with respect to coupling partners included a wide range of various substrates. Interestingly, the developed conditions are applicable for the synthesis of high-profile relevant biological agents from easily accessible starting materials. Furthermore, a leaching test confirmed the reaction heterogeneity and the catalyst was reused and recycled at least 8 times with trivial degradation in activity.