2007 Fiscal Year Final Research Report Summary
Development of novel ligands occupying the specified positions and their application to the synthesis of new hypervalent compounds
| Project/Area Number |
15105001
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Organic chemistry
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAWASHIMA Takayuki The University of Tokyo, Graduate School of Science, Professor (80011766)
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| Co-Investigator(Kenkyū-buntansha) |
KANO Naokazu University of Tokyo, Graduate School of Science, Associate Professor (00302810)
KOBAYASHI Junji University of Tokyo, Graduate School of Science, Associate Professor (90334242)
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| Project Period (FY) |
2003 – 2007
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| Keywords | Tetracoordinated 1, 2-iodoxetane / Oxidants / Tetradentate ligand / Carbaphosphatranes / Carbasilatrane / Highly coordinated disilanes / Silanolatoziruconium complex / Amino (ylide) carbene |
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| Research Abstract |
The object of this study is to develop novel ligands, which occupy the specific positions of hypervalent main group compounds on the basis of the steric and electronic stabilization effects, and synthesize the hypervalent compounds with novel frameworks by use of these ligands. Mainly, we have developed several ligands for pentacoordinated main-group-element compounds, such as a planar tridentate ligand which occupies two apical positions and one equatorial position, tetradentate ligands which occupy three equatorial positions and one apical position, a bulky dendrimer-type ligand which occupies the equatorial position, and the dithiocarboxylato ligand which bridges two highly coordinate main-group elements. As a result, we succeeded in applying tetracoordinated 1,2-iodoxetane as a thermally stable oxidant, synthesizing carbaphosphatranes and a carbasilatrane where three oxygen atoms and one arbon atom occupy the equatorial and apical positions, respectively, and synthesizing disilanes with bonds between pentacoordinated silicon atoms and between heptacoordinated silicon atoms.
In addition, we also succeeded in synthesizing their related compounds such as prophosphaalatrane containing phosphorus and aluminum, a cationic silanolatozirconium complex that has olefin polymerization activity, and an amino(ylide)carbene having the highest electron donating ability among the related carbenes known to date. As mentioned above, we achieved the construction of the novel hypervalent compounds bearing a thermodynamically unfavorable configuration by taking advantages of the ligands that we developed by ourselves and elucidation of their structures, bonding modes, and reactivities. We could obtain new knowledge based on new structures that would contribute significantly to the development of a new paradigm in main group chemistry.
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