2015 Fiscal Year Annual Research Report
Investigation of Transition Metal Base containing Frustrated Lewis Pairs for Potential Catalysts of Sustainable Chemical Transformations
| Project/Area Number |
15H06424
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| Research Institution | Hiroshima University |
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Principal Investigator |
SHANG RONG 広島大学, 理学(系)研究科(研究院), 助教 (70754216)
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| Project Period (FY) |
2015-08-28 – 2017-03-31
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| Keywords | synthesis / theoretical calculations / structure / bonding / metal complexes |
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| Outline of Annual Research Achievements |
In the 2015 fiscal year, the synthesis of the targeted ligand, the tri-tert-butylazadiboriridin, as well as a range of transition metal complexes as starting materials have been prepared for synthesising the targeted complexes. The reactions of the azadiboriridin ligand with the AuCl(L) (L=SMe2, PPh3) complexes have been carried out, from which two different Au(I) complexes, including the targeted complex featuring the designed TMB-FLP structural scaffold, were obtained. These new complexes have been structurally characterised by NMR spectroscopy and X-ray crystallography.
Theoretical calculations using the density functional theory (DFT) were also carried out for detailed bonding analyses of the newly obtained compounds. The results show very unusual electronic properties as anticipated. To gain further understanding of the structure and bonding of these complexes, systematic ligand modification will be necessary. This, and the new complexes' reactivity towards small molecules are currently under investigation.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
This research aims to synthesise and characterise structurally and electronically novel chelating and non-chelating Transition Metal Base-containing Frustrated Lewis Pairs (TMB-FLP) and study their reactivity towards small molecules to develop applications in activation and transformation of small molecules and catalysis. This work has been going well according to the proposed time line, even though some time was lost due to new laboratory set up related work.
As proposed in the research plan, the targeted ligand and metal starting materials including gold, iridium and rhodium complexes have been synthesised. Novel gold complexes have been successfully obtained and well characterised. DFT calculations have been carried out to gain insight into bonding and reactivity of these compound.
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| Strategy for Future Research Activity |
The newly obtained gold(I) complexes exhibited very unusual structures with unique bonding situations. Even though DFT calculations have been carried out, systematical modifications of the metal ligands are necessary for a better understanding of its electronic structure, which governs its reactivity. Therefore, different ligands for the gold(I) complex are now being synthesised for preparation of structural analogues of the newly obtained complexes. By detailed structural comparison among these complexes, we will be able to understand the effect of the ligands on their electronic properties and thus reactivity.
Meanwhile, in order to map the reactivity pattern of this new class of complexes, reactions of the newly synthesised gold complexes with small unsaturated molecules, including CO, and CO2 will also be carried out as planned. Their reactivity will be compared compared to gain insight in controlled selectivity for further development.
Lastly, reactions of the azaboriridin ligand with the more versatile iridium, rhodium complexes (already synthesised) will be carried out. Any new complex obtained will be structurally characterised. DFT calculations will also be carried out for a better understanding of the bonding within the molecule. when time permits, reactivity studies similar to those from the gold complexes will be also carried out for comparisons. This will allow broader evaluation of the molecular design concept proposed in this research and probe for future directions.
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