University of California, Los Angeles
Grant: $590,000 - National Science Foundation - Aug. 2, 2009
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Award Description: The present project is focused on reactions of electrophilic metal-carbon bonds with substrates featuring strong Câˆ'N bonds in order to understand the mechanism of intimate reaction steps. The breaking of Câˆ'N bonds in heterocycles is a significant reaction in hydrodenitrogenation processes.  The industrial heterogeneous catalysts for this energy intensive process operate at 300 â€' 500 °C and 200 atm H2.  Understanding the Câˆ'N bond breaking of homogeneous processes in the presence of transition metals offers two advantages: (1) Studies of homogeneous processes can elucidate the mechanism of the heterogeneous systems and (2) They can lead to novel processes under milder conditions where hydrogen usage is no longer required. Our preliminary results show that ring-opening of aromatic N-heterocycles can be initiated by metal-carbon sigma-bonded fragments. These results are different from existing examples, which all involved metal-element multiple bonds. Preliminary DFT calculations indicate that the ligand system employed by us, 1,1’-ferrocene diamide, may be unique in supporting electrophilic metal centers, which can Câˆ'H activate strong Lewis bases.
Project Description: We have begun to study the chemistry of metal complexes supported by various ferrocene-based ligands with the goal of determining the generality of the ring-opening reactions with aromatic N-heterocycles. Our results with scandium complexes indicate that steric and electronic factors both play important roles in achieving this difficult transformation. The use of transition metal centers other than scandium, such as yttrium, lutetium, and lanthanum, is being explored. Reactions between unsaturated substrates and the products of heterocycle Câˆ'H activation are being investigated. Avenues to use catalytic amounts of newly synthesized complexes in the heterocycle ring-opening reactions are being pursued. From a fundamental point of view it is important to determine the influence of the ferrocene backbone on the reactivity of the early transition metal centers. We have started to compare the reactivity of metal complexes supported by pincer and xanthene diamide ligands, which involve a nitrogen or oxygen instead of a metal center donor and are geometrically similar supporting ligands, to that of the ferrocene diamide complexes. Comparison with such ligands will establish if the interaction with the iron center is unique. Â
Infrastructure Description: N/A
Jobs Summary: UCLA is a world-class educational institution in the midst of an unprecedented financial crisis that threatens our mission to provide education, research and public service benefiting millions of people. ARRA funding to the University has enabled the creation and retention of jobs to support vital scientific research and training activities that would otherwise be severely constrained or eliminated through budget cuts. The type(s) of jobs created and retained by this ARRA-fund award includes: Faculty and Investigator positions. Scientific/Technical Professionals and Staff positions, such as Researchers, Post-Docs, Graduate Student Researchers, Project Managers and Statisticians. (Total jobs reported: 1)
Project Status: Less Than 50% Completed
This award's data was last updated on Aug. 2, 2009. Help expand these official descriptions using the wiki below.
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