Search

Chemoselective reduction of nitroarenes to arylamines is a core technology for the synthesis of numerous chemicals. The technology, however, relies on applying precious noble metal catalysts. We present our findings on the development of robust nanoporous covalent triazine frameworks (CTFs) as metal-free catalysts for the green chemoselective reduction of nitroarenes. The turnover frequency is found to be 43.03 h–1, exceeding activities of the heteroatom-doped carbon nanomaterials by a factor of 30. The X-ray photoelectron spectroscopy and control experiments provide further insights into the nature of active species for prompt catalysis. This report confirms the importance of quaternary ‘N’ and ‘F’ atom functionalities to create active hydrogen species via charge delocalization as a critical step in improving the catalytic activity.

Structural modification through binding interaction of plasma protein bovine serum albumin (BSA) with an extrinsic charge transfer fluorophore 5-(4-dimethylamino-phenyl)-penta-2,4-dienoic acid (DMAPPDA) and its response to external perturbation due to interactions with surfactantsodium dodecyl sulphate (SDS) have been explored at physiological pH by steady state absorption, emission, fluorescence anisotropy, red edge excitation shift, far-UV circular dichroism and time resolved spectral measurements in combination with Molecular Docking and Molecular Dynamics (MD) simulation. Interaction of the probe with BSA is reflected by a small change in protein secondary structure with fluorescence enhancement and blue shift of probe emission. Molecular docking studies revealed that the probe binds to the hydrophobic cavity of sub-domain IIA of BSA. The distance for energy transfer from the tryptophan of BSA to the bound DMAPPDA measured by Fluorescence Resonance Energy Transfer is in good agreement with the molecular docking results. MD simulation predicts stabilization of the complex with respect to the bare molecule. Interaction of BSA and SDS with DMAPPDA supports the movement of the probe from hydrophilic free water region to a more restricted hydrophobic zone inside the protein.

The selectivity and sensitivity of N,N'-bis(4-diethylaminosalicylidene)hydrazine (sensor 1) toward Cu2+ion have been established both by distinct “naked-eye” color change as well as UV–vis spectrophotometry. Sensor 1formed 1:1 complex with Cu2+ion where the most stable s-trans form of the sensor is trapped in the high energy conformer. Single-crystal X-ray structure of sensor 1supports its s-trans conformation. Theoretical calculations support well the experimental result.

Dichtel and co-workersdramatically improve electrochemical performance of conductive polymers, as explained here by Jiang and co-workers.