The Reincarnation of the Hieber Anion [Fe(CO)3(NO)]- - a New Venue in Nucleophilic Metal Catalysis

Nowadays demand for selective, energy-efficient, and sustainable chemical transformations has spur-red an increasing interest in the development of sustainable metal catalysis. This expression defines a type of catalytic transformation in which non-toxic, readily available and inexpensive, stable metal complexes are used for catalysis. The increasing prices for energy and noble metals, which are commonly used for catalysis, represent an economical and ecological dilemma. If the price for a catalyst exceeds the savings on the energy side an industrial application does not make sense. As a consequence of this dilemma, chemists are looking for exit strategies with catalysis by small organic molecules (organocatalysis) or by inexpensive, readily available metal complexes (sustainable metal catalysis) being the most prominent ones. It is an irony that these two major catalytic strategies are based on research that had been initiated several decades ago but was somehow forgotten. In the present Microreview, the story of the reincarnation of another forgotten metal complex species, that celebrates its 50th birthday this year, will be told, the [Fe(CO)(3)(NO)](-) anion. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)