Biological and catalytic evaluation of Ru(II)‐p‐cymene complexes of Schiff base ligands: Impact of ligand appended moiety on photo‐induced DNA and protein cleavage,cytotoxicity and C‐H activation

Two organometallic Ru(II)‐p‐cymene complexes of the type [Ru(η⁶‐p‐cymene)(L)Cl]PF₆ 1 and 2 , where L is N,N‐bis(4‐isopropylbenzylidene)ethane‐1,2‐diamine (bien, L1 ) or N,N‐bis (pyren‐2‐ylmethylene)ethane‐1,2‐diamine (bpen, L2 ) have been prepared and characterized well. Because of appended pyrenyl groups in coordinated bpen ligand, the complex 2 exhibits higher DNA and protein binding than complex 1 in which isopropylbenzyl groups are incorporated. Interestingly, the luminescent characteristic complex 2 is unique in displaying DNA cleavage after light activation by UVA light at 365 nm through oxygen dependent mechanism. AFM analysis attests the photo‐induced DNA fragmentation ability of complex 2 . Also, the complex 2 cleaves the protein after light exposure in a non‐specific manner suggesting that it can act as a protein photo cleaving agent. In contrast to the trend of DNA and protein interaction of complexes, the complex 1 exhibits cytotoxic activity against human breast carcinoma ( MCF‐7 ) and liver carcinoma ( HepG2 ) with potency higher than that of complex 2 due to enhanced hydrophobicity of isopropyl groups present in p‐cymene and bien ligands. Indeed, complex 2 is inactive against MCF‐7 and HepG2 cancer cell lines even up to 200 μM concentration. The AO/EB staining assay reveals that the complex 1 is able to induce late apoptotic mode of cell death in breast cancer cells, which is further confirmed by inter‐nucleosomal DNA cleavage. Furthermore, the complexes 1 and 2 are evaluated for their catalytic activities and found to be working well for the β‐carboline directed C–H arylation to afford the desired products in good yield (40–47%).     

Advancing MXene Electrocatalysts for Energy Conversion Reactions: Surface,Stoichiometry, and Stability

MXenes, due to their tailorable chemistry and favourable physical properties, have great promise in electrocatalytic energy conversion reactions. To exploit fully their enormous potential, further advances specific to electrocatalysis revolving around their performance, stability, compositional discovery and synthesis are required. The most recent advances in these aspects are discussed in detail: surface functional and stoichiometric modifications which can improve performance, Pourbaix stability related to their electrocatalytic operating conditions, density functional theory and advances in machine learning for their discovery, and prospects in large scale synthesis and solution processing techniques to produce membrane electrode assemblies and integrated electrodes. This Review provides a perspective that is complemented by new density functional theory calculations which show how these recent advances in MXene material design are paving the way for effective electrocatalysts required for the transition to integrated renewable energy systems.     

Transformation of hydrophobic surface into superhydrophobic surface by interfacial flower like silver films

Fabrication of superhydrophobic surface was achieved by electroless deposition of silver film and subsequent immersion into a mixture of stearic acid and cysteamine. The resultant superhydrophobic surface with flower and fall‐leaves like structure showed lotus leaf effect with the water contact angle of about 154° making copper surface water repellant. Copyright © 2014 John Wiley & Sons, Ltd.     

Experimental design approach for petrochemical waste water treatment using solar assisted photo Fenton process

In this study, the effect of photo-Fenton process on the treatment of petrochemical waste water treatment was investigated. The influence of process conditions were determined by factorial design. Optimization of the process conditions were performed by central composite design. Under, optimized conditions lab scale and solar assisted pilot scale of petrochemical waste water treatment was performed. Three factors namely initial pH, H₂O₂ concentration (mM) and Fe²⁺ concentration (mM) executed the essential role in petrochemical waste water treatment. Central composite design resulted in the prediction of optimized value as 6.5 initial pH, 15.65 mM of H₂O₂ concentration and 2.09 mM of Fe²⁺ concentration. Under these conditions, the reduction in chemical oxygen demand (COD) percentage reached about 68.67 ± 2.8% after 280 min in pilot scale of solar assisted photo Fenton process of petrochemical waste water treatment. Thus, experimental design combined with advanced Fenton process can become a feasible unconventional method for petrochemical waste water treatment.     

Stuffed Tridymite Structures: Synthesis,Structure, Second Harmonic Generation,Optical, and Multiferroic Properties

The stuffed tridymite structure Ba(Zn/Co)_1−xSi_1−xM_2xO₄ (M=Al³⁺ and Fe³⁺) is explored for the possible multiferroic behavior and to develop new inorganic colored materials. The compounds were synthesized by employing conventional solid-state chemistry methods in the temperature range 1100–1175 °C for 24 h. The powder X-ray diffraction (PXRD) and Rietveld refinement studies indicate that the compounds stabilize in the P63 space group (no. 173). The refinement results were also rationalized by employing Raman spectroscopic studies. The compounds were found to be second harmonic generation (SHG) active and show weak ferroelectric behavior. The co-substitution of Co²⁺ and Fe³⁺ in the structure gives rise to a weak ferromagnetic behavior to the compound, BaCo_0.75Si_0.75Fe_0.5O₄, making it a multiferroic material. The optical studies on the prepared compounds exhibited blue color (Co²⁺ in T_d geometry), purple color (Ni²⁺ in T_d geometry), and simultaneous substitution of Co²⁺ and Fe³⁺ gives rise to blue-green color owing to metal-to-metal charge transfer (MMCT) effect.     

Magnetic properties of carbon nanosheets

Two-dimensional carbon nanosheets have been fabricated using inductively coupled radio frequency plasma-enhanced chemical vapour deposition. The structural properties of the nanosheets have been characterised using atomic force microscopy, scanning electron microscopy and X-ray diffractometer. The magnetisation of the samples was studied using vibrating sample magnetometer. The magnetisation of the nanosheets was found to be diamagnetic for fast synthesis processes (30 and 60 min). On the other hand, the nanosheets exhibited a weak ferromagnetic response for the slow (120 min) synthesis process. Energy dispersive spectrometry and atomic absorption spectroscopy confirmed that the magnetisation exhibited by the carbon nanosheets was an intrinsic property and that it was not due to contamination from the substrate. Raman spectroscopy studies revealed that the ferromagnetic carbon nanosheets have a higher ratio (1.20) of graphite peak (I _G) to disordered peak (I _D) than normally expected (0.75–0.90). Available data indicated that the magnetisation was due to the presence of structural disorders.