Band 2, Heft 4

Due to their unique steric and electronic properties, air-stability and modular structure, chiral hybrid P,N-ferrocenyl ligands play a prominent role in the field of asymmetric catalysis. This report aims to give a concise introduction to the syntheses of chiral hybrid P,N-ferrocenyl ligands and presents an overview of their application in enantioselective catalysis. This review is of special interest to chemists working on ligand design and asymmetric catalysis, as well as to the broader organic and inorganic community.

A process to isolate and purify an industrial aqueous sodium nitrite bearing by-product stream was developed and built. This process stream was formerly incinerated at significant cost. Biotreatment, supercritical water oxidation, nanofiltration, molten salt oxidation, and carbon treatment were explored as alternative remediation processes. Aspects of these technologies are discussed. Ultimately, it was found that activated carbon purification of the nitrite bearing wastewater was the most economical and safest methodology to produce a product that was found to have utility in the market place. Key elements and the environmental impact of the carbon-based technology are presented.

A microwave unit interfaced with a gas-loading accessory is used as a tool for facilitating the palladium-catalyzed decarboxylative Heck reaction of 2,6-dimethoxybenzoic acid and methyl acrylate, using molecular oxygen as the oxidant. The reaction is complete in less time and at a lower catalyst loading than when using conventional approaches. The reaction is scaled up using continuous-flow processing, employing a reactor in which both gas input and heating can be performed simultaneously. An 86% isolated product yield is obtained. This proof-of-principle study paves the way for the technology to be used in other cases of these increasingly popular decarboxylative coupling reactions.

2′-Hydroxychalcones, on reaction with urea-hydrogen peroxide complex (UHP) and potassium hydroxide moist with ethanol, under grinding conditions, provided 3-hydroxy-2-phenyl-4 H -chromen-4-ones (3-hydroxyflavones or flavonols) in excellent yields. Epoxidation followed by oxidative cyclization takes place simultaneously in a single pot reaction.

Ruthenium tris-bipyridine derived complexes functionalized by either carboxyl or phosphonyl groups were tested as sensitizers for the photocatalytic reduction of carbon dioxide in the presence of nickel cyclam acting as a catalyst, and a sacrificial donor. These systems were shown to be as efficient as the unsubstituted compounds in solution. Covalent binding to titania nanoparticles gave slightly different results from those with the untreated semiconductor.