Iridium(III)-Catalyzed Intermolecular C(sp3 )-H Insertion Reaction of Quinoid Carbene: A Radical Mechanism.

Described herein is an IrIII /porphyrin-catalyzed intermolecular C(sp3 )-H insertion reaction of a quinoid carbene (QC). The reaction was designed by harnessing the hydrogen-atom transfer (HAT) reactivity of a metal-QC species with aliphatic substrates followed by a radical rebound process to afford C-H arylation products. This methodology is efficient for the arylation of activated hydrocarbons such as 1,4-cyclohexadienes (down to 40 min reaction time, up to 99 % yield, up to 1.0 g scale). It features unique regioselectivity, which is mainly governed by steric effects, as the insertion into primary C-H bonds is favored over secondary and/or tertiary C-H bonds in the substituted cyclohexene substrates. Mechanistic studies revealed a radical mechanism for the reaction.

A coagulation-powdered activated carbon-ultrafiltration--multiple barrier approach for removing toxins from two Australian cyanobacterial blooms.

Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition.