The coupling of aryl or vinyl halides with terminal acetylenes catalysed by palladium and other transition metals, commonly termed as Sonogashira cross-coupling reaction, is one of the most important and widely used sp2–sp carbon–carbon bond formation reactions in organic synthesis, frequently employed in the synthesis of natural products, biologically active molecules, heterocycles, molecular electronics, dendrimers and conjugated polymers or nanostructures. This critical review focuses on developments in the Sonogashira reaction achieved in recent years concerning catalysts, reaction conditions and substrates (352 references).

Recent advances in Sonogashira reactions

Microwave food processing—A review

Efforts to use microwaves in material processing are gradually increasing. However, the phenomena associated with the processing are less understood; popular mechanisms such as dipolar heating and conduction heating have been mostly explored. The current paper reviews most of the significant phenomena that cause heating during microwave–material interaction and heat transfer during microwave energy absorption in materials. Mechanisms involved during interaction of microwave with characteristically different materials – metals, non-metals and composites (metal matrix composites, ceramic matrix composites and polymer matrix composites) have been discussed using suitable illustrations. It was observed that while microwave heating of metal based materials is due to the magnetic field based loss effects, dipolar loss and conduction loss are the phenomena associated with the electric field effects in microwave heating of non-metals. Challenges in processing of advanced materials, particularly composites have been identified from the available literature; further research directions with possible benefits have been highlighted.

Microwave–material interaction phenomena: Heating mechanisms, challenges and opportunities in material processing

Microwave heating is rapidly emerging as an effective and efficient tool in various technological and scientific fields. A comprehensive understanding of the fundamentals of microwave-matter interactions is the precondition for better utilization of microwave technology. However, microwave heating is usually only known as dielectric heating, and the contribution of the magnetic field component of microwaves is often ignored, which, in fact, contributes greatly to microwave heating of some aqueous electrolyte solutions, magnetic dielectric materials and certain conductive powder materials, etc. This paper focuses on this point and presents a careful review of microwave heating mechanisms in a comprehensive manner. Moreover, in addition to the acknowledged conventional microwave heating mechanisms, the special interaction mechanisms between microwave and metal-based materials are attracting increasing interest for a variety of metallurgical, plasma and discharge applications, and therefore are reviewed particularly regarding the aspects of the reflection, heating and discharge effects. Finally, several distinct strategies to improve microwave energy utilization efficiencies are proposed and discussed with the aim of tackling the energy-efficiency-related issues arising from the application of microwave heating. This work can present a strategic guideline for the developed understanding and utilization of the microwave heating technology.

Review on Microwave-Matter Interaction Fundamentals and Efficient Microwave-Associated Heating Strategies

Microwave-assisted synthesis of metal oxide/hydroxide composite electrodes for high power supercapacitors – A review

Effect of lanthanum doping in ceria abrasives on chemical mechanical polishing selectivity for shallow trench isolation

Selectivity (oxide/nitride polish rate) is a critical factor during chemical mechanical polishing (CMP) of shallow trench isolation (STI) structure, and it can be modified by adding amino acids to the slurry. The role of adsorption of the amino acids L-proline and L-arginine, on silicon dioxide and silicon nitride surfaces was characterized as a function of pH and concentration using thermogravimetric analysis. The results suggest that the adsorption behavior does not correlate with the polishing behavior of STI CMP and hence it may not play a key role in changing the selectivity.

http://www.che.iitm.ac.in/~srinivar/PrePrint/STIAdsorption.Nagendra.2006.pdf

Role of Amino-Acid Adsorption on Silica and Silicon Nitride Surfaces during STI CMP

Anodic dissolution of copper in glycine solution at various hydrogen peroxide concentrations was investigated. The dissolution rate increases, reaches a maximum, and then decreases with hydrogen peroxide concentration. Anodic polarization studies and electrochemical impedance spectroscopy (EIS) studies were carried out to determine the mechanistic pathway of anodic dissolution of copper in glycine system at three different hydrogen peroxide concentrations: one at low hydrogen peroxide concentration in the active dissolution region, another in the maximum dissolution region, and the third at the high hydrogen peroxide concentration in the post-peak-dissolution region. The EIS data in complex plane plots show presence of two capacitance loops and one negative capacitance loop. The impedance plot patterns strongly depend on the hydrogen peroxide concentration in solution. Reaction mechanism analysis technique was employed to model the EIS data. A three-step mechanism with two intermediate adsorbates and a parallel dissolution by catalytic mechanism simulates EIS patterns which match the experimental trends. The intermediates are likely to be cupric and cuprous oxides. The essential features of impedance spectra at various overpotentials at three different hydrogen peroxide concentrations are captured by the proposed mechanism. The results also show that the film present on the copper surface in glycine and hydrogen peroxide solutions does not passivate the surface.

S. Ramanathan

Papers

Effect of lanthanum doping in ceria abrasives on chemical mechanical polishing selectivity for shallow trench isolation

Role of Amino-Acid Adsorption on Silica and Silicon Nitride Surfaces during STI CMP

Electrochemical impedance spectroscopic studies of copper dissolution in glycine–hydrogen peroxide solutions

Abrasive and additive interactions in high selectivity STI CMP slurries

Effect of HF Concentration on Anodic Dissolution of Titanium