There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

In this review, we highlight the use of organic photoredox catalysts in a myriad of synthetic transformations with a range of applications. This overview is arranged by catalyst class where the photophysics and electrochemical characteristics of each is discussed to underscore the differences and advantages to each type of single electron redox agent. We highlight both net reductive and oxidative as well as redox neutral transformations that can be accomplished using purely organic photoredox-active catalysts. An overview of the basic photophysics and electron transfer theory is presented in order to provide a comprehensive guide for employing this class of catalysts in photoredox manifolds.

Organic Photoredox Catalysis

The Pharmacological Basis of Therapeutics A Textbook of Pharmacology, Toxicology and Therapeutics for Physicians and Medical Students. By Prof. Louis Goodman and Prof. Alfred Gilman. Pp. xiii + 1383. (New York: The Macmillan Company, 1941.) 50s. net.

The Pharmacological Basis of Therapeutics

Light can be considered an ideal reagent for environmentally friendly, 'green' chemical synthesis; unlike many conventional reagents, light is non-toxic, generates no waste, and can be obtained from renewable sources. Nevertheless, the need for high-energy ultraviolet radiation in most organic photochemical processes has limited both the practicality and environmental benefits of photochemical synthesis on industrially relevant scales. This perspective describes recent approaches to the use of metal polypyridyl photocatalysts in synthetic organic transformations. Given the remarkable photophysical properties of these complexes, these new transformations, which use Ru(bpy)(3)(2+) and related photocatalysts, can be conducted using almost any source of visible light, including both store-bought fluorescent light bulbs and ambient sunlight. Transition metal photocatalysis thus represents a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.

Visible light photocatalysis as a greener approach to photochemical synthesis

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

Advanced oxidation process-mediated removal of pharmaceuticals from water: A review.

In recent years, concerns about the occurrence and fate of active pharmaceutical ingredients, solvents, intermediates and raw materials that could be present in water and wastewater including pharmaceutical industry wastewater has gained increasing attention. Traditional wastewater treatment methods, such as activated sludge, are not sufficient for the complete removal of active pharmaceutical ingredients and other wastewater constituents from these waters. As a result, complementary treatment methods such as membrane filtration, reverse osmosis and activated carbon are often used in conjunction with the traditional methods for treatment of industrial wastewater. Most of the literature published to date has been on the treatment of municipal wastewater. However, there is a growing body of research that looks at the presence of active pharmaceutical ingredients in industrial wastewater, the treatment of these wastewaters and the removal rates. This article, reviews these treatment methods and includes both traditional methods and advanced oxidation processes. The paper concludes by showing that the problem of pharmaceuticals in wastewaters cannot be solved merely by adopting end of pipe measures. At source measures, such as replacement of critical chemicals, reduction in raw material consumption should continue to be pursued as the top priority.

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Treatment options for wastewater effluents from pharmaceutical companies

Heterogeneous photocatalysis using the semiconductor titanium dioxide (TiO2) has proven to be a promising treatment technology for water purification. The effectiveness of this oxidation technology for the destruction of pharmaceuticals has also been demonstrated in numerous studies. This review highlights recent research on TiO2 photocatalytic treatment applied to the removal of selected pharmaceuticals. The discussions are tailored based on the therapeutic drug classes as the kinetics and mechanistic aspects are compound dependent. These classes of pharmaceuticals were chosen because of their environmental prevalence and potential adverse effects. Optimal operational conditions and degradation pathways vary with different pharmaceutical compounds. The main conclusion is that the use of TiO2 photocatalysis can be considered a state-of-the-art pharmaceutical wastewater treatment methodology. Further studies are, however, required to optimize the operating conditions for maximum degradation of multiple pharmaceuticals in wastewater under realistic conditions and on an industrial scale.

/pdf/titanium-dioxide-photocatalysis-for-pharmaceutical-35woo1gtou.pdf

Titanium dioxide photocatalysis for pharmaceutical wastewater treatment

The use of a confined space in which to carry out reactions has proven popular in recent years, as demonstrated by the large volume of work published on ‘molecular microreactors’ such as zeolites, micelles and nanoparticles. This article looks at reactions in microstructured reactors, also known as microchannelled reactors or microreactors. In general, these consist of a ‘chip’ with narrow channels etched into it. Microstructured reactors have been the subject of several review articles to date, focusing on preparation, types of reactions that may be carried out and on the potential for ‘green’ applications. However, the use of microstructured reactor technology in photochemistry has, until now, not been subject to review. This perspective aims to outline the work done to date in this area and in particular to demonstrate the advantages and future prospectives of this technology in photochemical processes. Photochemistry in microstructured reactors is an emerging area of interest and to date has demonstrated significant potential as a viable alternative to traditional photochemical synthesis.

/pdf/micro-photochemistry-photochemistry-in-microstructured-106ahn8fok.pdf

Micro-photochemistry: photochemistry in microstructured reactors. The new photochemistry of the future?

With a new editorship of three highly respected scientists, the third edition of this bestselling handbook continues to provide an authoritative and unique resource for those working and studying in the areas of photochemistry and photobiology. This edition uses the IUPAC glossary of terms for photochemistry as a guide in the structure of the contents. Leading experts offer enlightening contributions on traditional topics, current trends, and future directions. New and updated topics in this edition include photosensoring, photoimmunology, artificial photosynthetic systems, phototoxicity of drugs, and much more.

Michael Oelgemöller

Papers

Advanced oxidation process-mediated removal of pharmaceuticals from water: A review.

Treatment options for wastewater effluents from pharmaceutical companies

Titanium dioxide photocatalysis for pharmaceutical wastewater treatment

Micro-photochemistry: photochemistry in microstructured reactors. The new photochemistry of the future?

CRC handbook of organic photochemistry and photobiology