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Reactive and Structurally Unusual Organo Complexes of Transition Metals

English title Reactive and Structurally Unusual Organo Complexes of Transition Metals
Applicant Berke Heinz
Number 126950
Funding scheme Project funding (Div. I-III)
Research institution Institut für Chemie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Inorganic Chemistry
Start/End 01.10.2009 - 31.03.2012
Approved amount 471'867.00
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Keywords (4)

Hydrogen catalysis; Molecular Electronics; Metal-free hydrogenation; Metal-induced hydrogenation

Lay Summary (English)

Lead
Lay summary
Various fundamental research approaches were chosen to improve the performance of hydrogen catalyses. Metal-induced and metal-free hydrogenations and transfer hydrogenations will be explored, both with the main goal to escape from noble metals as the catalytic auxiliary. Solution of this problem seems to come from the so-called ionic hydrogenation, which is expected to proceed with non-noble Metal mediated splitting of hydrogen in a formally heterolytic way. Furthermore this project deals with so-called metal-free catalysis of hydrogenations and transfer hydrogenations, where main group elements including carbon are utilized as reaction centers. This very new research field is as yet relatively unexplored. Such main group element induced hydrogenations are yet poor in activity and selectivity. Our approach to improve these major catalysis parameters is based on amplification of the effects originating from the involved Lewis acids. Transfer hydrogenation, which can also be used as hydrogenations, are also sought to be utilized on the metal-free basis. But as a very new chemistry, it has great perspectives to lead to efficient chemical hydrogen storage devices, since hydrogen storage compounds need effective hydrogenations and dehydrogenations and transfer hydrogenations as ways for hydrogen transformation. Another project part deals with the exploration of a chemistry constructing molecular electronic devices. The general trend to miniaturize electronic parts ends at the level of molecules. Their electronic properties have to be appropriately adjusted. For a molecular wire this concerns molecular electronic conductivity. Our approach utilizes the redox-activity transition metal centers as end groups of the wire system. These centers are bridged by "conducting" organic units with extended mainly acetylenic ? systems. The search for effective systems includes the transition metals molybdenum, tungsten, rhenium, manganese and iron. Tuning efforts with respect to metals and their ligands and the bridges are based also on the feed-back from measurements of molecular conductivity. Other physical methodology is used to evaluate various physical properties of these compounds. A correlation of these parameters and also of the structure of such compounds is sought to establish a catalogue to eventually allow predictions on the molecular conductivity of such compounds. Molecular wires are simplest electronic devices. From their chemistry related properties, we hope to learn about the ways to construct molecular diodes and field effect transistors.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Incorporation of active metal sites in MOFs via in situ generated ligand deficient metal-linker complexes
Barman S, Furukawa H, Blacque O, Venkatesan K, Yaghi OM, Jin GX, Berke H (2011), Incorporation of active metal sites in MOFs via in situ generated ligand deficient metal-linker complexes, in CHEMICAL COMMUNICATIONS, 47(43), 11882-11884.
Homogeneous Hydrogenations of Nitriles Catalyzed by Rhenium Complexes
Rajesh K, Dudle B, Blacque O, Berke H (2011), Homogeneous Hydrogenations of Nitriles Catalyzed by Rhenium Complexes, in ADVANCED SYNTHESIS & CATALYSIS, 353(9), 1479-1484.
Rhenium Nitrosyl Complexes Bearing Large-Bite-Angle Diphosphines
Dudle B, Rajesh K, Blacque O, Berke H (2011), Rhenium Nitrosyl Complexes Bearing Large-Bite-Angle Diphosphines, in ORGANOMETALLICS, 30(11), 2986-2992.

Associated projects

Number Title Start Funding scheme
141272 Non-precious metal hydrogenations and hydrogen storage 01.04.2012 Project funding (Div. I-III)
116285 Reaktive und strukturell ungewöhnliche Organokomplexe mit Uebergangsmetallen 01.04.2007 Project funding (Div. I-III)
116285 Reaktive und strukturell ungewöhnliche Organokomplexe mit Uebergangsmetallen 01.04.2007 Project funding (Div. I-III)

Abstract

Various fundamental research approaches were chosen to improve the performance of hydrogen catalyses. Metal-induced and metal-free hydrogenations and transfer hydrogenations will be explored, both with the main goal to escape from noble metals as the catalytic auxiliary. Solution of this problem seems to come from the so-called ionic hydrogenation, which is expected to proceed with splitting of hydrogen in a formally heterolytic way and subsequent transfer of a hydride and a proton onto the substrate to be hydrogenated. The great advantage of ionic hydrogenations over the common Wilkinson type hydrogenations is that it can make use of middle transition elements like molybdenum, tungsten and rhenium as elaborated in this project. Furthermore this project deals with so-called metal-free catalysis of hydrogenations and transfer hydrogenations, where main group elements including carbon are utilized as reaction centers. This very new research field is as yet relatively unexplored. Such main group element induced hydrogenations are yet poor in activity and selectivity. Our approach to improve these major catalysis parameters is based on amplification of the effects originating from the involved Lewis acids. Better Lewis acids could eventually lead to better catalysis. Transfer hydrogenation, which can also be used as hydrogenations, are also sought to be utilized on the metal-free basis. However, this area research is practically starting from scratch. But as a very new chemistry, it has great perspectives to in the end lead to efficient chemical hydrogen storage devices, since hydrogen storage compounds need effective hydrogenations and dehydrogenations and transfer hydrogenations as ways for hydrogen transformation. Another project part deals with the exploration of a chemistry constructing molecular electronic devices. The general trend to miniaturize electronic parts ends at the level of molecules. Their electronic properties have to be appropriately adjusted. For a molecular wire this concerns molecular electronic conductivity. Our approach utilizes the redox-activity transition metal centers as end groups of the wire system. These centers are bridged by “conducting” organic units with extended mainly acetylenic p systems. The search for effective systems includes the transition metals molybdenum, tungsten, rhenium, manganese and iron. Tuning efforts with respect to metals and their ligands and the bridges are based also on the feed-back from measurements of molecular conductivity. Other physical methodology is used to evaluate various physical properties of these compounds. A correlation of these parameters and also of the structure of such compounds is sought to establish a catalogue to eventually allow predictions on the molecular conductivity of such compounds. Molecular wires are simplest electronic devices. From their chemistry related properties, we hope to learn about the ways to construct molecular diodes and field effect transistors.
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