Biorelevant Metals in Sustainable Metal Catalysis—A Survey

Abstract

A growing world population and increasing energy demands are without a doubt the most important challenges for mankind within this century. Catalysis is a key technology in various fields of chemistry and offers the potential to increase the material output of chemical synthesis without an unreasonable increase in the energy necessary for the production of new materials. Hence, the various disciplines of catalysis are “sustainable” by definition. However, for a wide range of catalytic transformations to take the necessary next step from academic research to industrial application, the catalytic processes do not only have to be sustainable with regard to the substrate‐to‐product conversions, but they also have to be sustainable with regard to parameters such as solvent, energy source, and the nature of the catalyst. Currently, the vast majority of transition‐metal‐catalyzed homogenous reactions are based upon late and expensive transition‐metal complexes. In the present review we summarize the current state of the art in sustainable metal catalysis, that is, catalysis based upon inexpensive biorelevant metals such as Ca, Mg, V, Mo, Mn, Fe, Co, Ni, Cu, Zn, B, Si, and Se. These metals are part of nature’s catalytic toolbox and have experienced a tremendous comeback in metal catalysis within the past 10 years.

Co-based heterogeneous catalysts from well-defined α-diimine complexes: Discussing the role of nitrogen

“…In this regard, the design of catalytic systems based on abundant and biocompatible metals is an important goal for the implementation and progress of green and sustainable chemistry. Hence, transition metals such as Fe, Co and Cu are ideal candidates, which meet these requirements [7][8][9][10]. As a matter of fact, these elements are among the most abundant metals in the Earth's upper crust, thus being readily accessible [11].…”

LiAlH4: From Stoichiometric Reduction to Imine Hydrogenation Catalysis

“…Societal pressure to use sustainable "green" production processes [7] is the driving force for atom-economical catalytic imine hydrogenation using the simplest, most widely accessible reducing agent:H 2 . [13][14][15] Recently, Cp*ZnH and iBu 2 AlH were found to be catalytically active in imine hydrogenation but harsh working conditions,including high H 2 pressure (70-100 bar), are needed. [9] With few exceptions, [10,11] existing catalysts are generally based on late transition metals (Rh, Ir).…”

Using sustainable metals to carry out “green” transformations: Fe- and Cu-catalyzed CO2 monetization

“…Williams and co-workers reported the synthesis of a novel dinuclear iron(III) catalyst (38), which was successfully applied in the coupling of epoxides with CO 2 ( Figure 16) [100]. In specific, complex 38 displayed high catalytic activity in the copolymerisation of cyclohexene oxide and CO 2 , under mild conditions, affording the copolymer product in excellent yields with a turnover number of 2570.…”