Design and synthesis of redox active diindanes

Abstract

The field of Green Chemistry seeks to reduce the risks and environmental impact associated with chemicals and chemical processes. To serve as guidelines for this purposeful design, Anastas and Warner introduced the 12 Principles of Green Chemistry. One of these principles, catalysis, is key as the use of chemical catalysts eliminates waste that would result from the use of stochiometric amounts of reactant. Many of the most successful and widespread redox catalysts in industry today feature precious heavy transition metals, such as palladium and rhodium, though the toxicity and environmental impact of these metals is undesirable. In contrast to these expensive transition metals, the base main group metal indium possesses several characteristics that make it appealing for green catalysis. Indium compounds are relatively non-toxic and have potential use as Lewis acid catalysts in aqueous solution. Indium is typically trivalent and not intrinsically redox active, which necessitates the design of indium compounds in lowered oxidation states to impart redox activity. The current work seeks to synthesis and characterize the novel redox active diindane [(NCN)2In2(naphth)] (1) which will ultimately be tested as a redox active green catalyst. The synthetic routes explored and the structural characterization of the novel compounds (NCN)InBr2 (6) and [(NCN)In]2(naphth)2 (8) are reported.