2013 Fiscal Year Research-status Report
シリレンおよびゲルミレンを配位子とするシュロック型遷移金属錯体の合成と構造
| Project/Area Number |
24550038
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| Research Institution | University of Tsukuba |
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Principal Investigator |
LEE Vladimir 筑波大学, 数理物質系, 講師 (90375410)
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| Keywords | Schrock-type complexes / silylene / germylene / early transition metals / [2+2] cycloaddition / bicyclo[1.1.0]butane / metallacyclobutane / heavy Group 14 elements |
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| Research Abstract |
We expect to develop a new synthetic route to the Schrock-type silylene and germylene complexes of the early transition metals. These novel coordination compounds are expected to be the efficient precursors for the [2 + 2] cycloadditions with unsaturated reagents in the silicon and germanium variations of the industrially very important metathesis process.
In the first year of the project, we synthesized the Schrock-type silylene and germylene complexes unprecedented in silicon and germanium chemistry. As the precursors for the preparation of these complexes, we used alkali and alkaline earth metal derivatives of the "heavy" cyclobutadiene [(R3Si)4E4](2-) 2[K(+)] and "heavy" bicyclo[1.1.0]butane [(R3Si)4E4](2-) [Ca(2+)] types (E = Si, Ge), very efficient in the synthesis of multiply bonded derivatives inaccessible in any other way. The reaction of these dianionic derivatives with the titanocene dichloride Cp2TiCl2 provided the the desired Schrock-type complexes, possessing Ti(L)=E double bond stabilized by the external Lewis basic ligand L.
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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
In the second year of the project, we investigate the [2 + 2] cycloaddition reactions of the newly synthesized Schrock-type titanium silylene and germylene complexes with a variety of unsaturated reagents, such as alkyl-, aryl-, silyl-substituted alkenes, alkynes, dienes and carbonyl compounds (formaldehyde, benzaldehyde, benzophenone, etc.). The reactions of such type, forming four-membered ring cycloaddition products, are still unprecedented in the silylene and germylene transition metal complexes chemistry.
Both titanium silylene and germylene complexes effectively react with a variety of the terminal alkynes (phenylacetylene, trimethylsilylacetylene, 1-hexyne, etc.) and nitriles (benzonitrile, pivalonitrile, etc.), regioselectively forming the corresponding [2+2] cycloadducts. The structures, physico-chemical properties and formation mechanism of these cycloadducts are studied by means of NMR spectroscopy, X-ray crystallography and high-level computations.
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| Strategy for Future Research Activity |
In the final third year of the project, we will expand the range of the group 4 metals to prepare also zirconium and hafnium silylene and germylene complexes. These complexes will be also tested for the use in the [2+2] cycloaddition reactions with the unsaturated substrates. Particular attention will be paid for the reaction of the complexes with ethylene and acetylene, because [2+2] cycloaddition products of these reactions are expected to undergo cycloreversion reactions. Such cycloreversion will provide a novel effective access to a variety of the multiply-bonded derivatives featuring double or triple bond to silicon or germanium atoms, as the key step toward the silicon or germanium versions of the olefin metathesis process.
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| Expenditure Plans for the Next FY Research Funding |
次年度使用額725326円であるが，平成２４年度の学術研究助成基金助成金からの繰越が974746円であり，平成２５年度分の助成金は110000円だった．つまり，平成２５年度の収支に限れば，支出が1287067円であり，当初の計画通りに使用したといえる．一方で一昨年からの繰越金のおよそ86%が平成２６年度分に繰り越されるわけだが，昨年度当初は共同研究等による学会発表に関する旅費の増加を見込んでいた．しかし，研究進捗状況を考慮して，最終年度での研究発表を充実すべきとなったため，使用額が見込みより低くなった．
繰越金の725326円は，当初計画に新たに加えることとして，本研究課題でえた成果の発表および新たなる共同研究への発展として利用する．具体的には2016年８月に予定されている３年に一度の当該分野の国際学会に出席し，研究発表を行うと同時に情報収集，研究協力体制の強化を進める．この国際学会はBerlin で開催され，およそ５００人程度の出席者のある重要な学会である．
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