Stabilization effects on labile chemical species by confinement in the zeolite's nanopores and its application to novel organic reactions

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H04562
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Catalyst/Resource chemical process
• Research Institution: Tokyo University of Agriculture (2018-2019); The University of Tokyo (2016-2017)
• Principal Investigator: ONAKA Makoto 東京農業大学, 生命科学部, 教授 (10144122)
• Co-Investigator(Kenkyū-buntansha): 増井 洋一 東京大学, 大学院総合文化研究科, 助教 (60447323)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: NaYゼオライト / AgYゼオライト / ハードイオン / ソフトイオン / ジフェニルケテン / 累積二重結合 / 配位形態

Outline of Final Research Achievements

We investigated how a polar cumulene molecule like diphenylketene was accommodated in the faujasite zeolite pores based on 13C CP/MAS and DD/MAS NMR analyses as well as quantum chemical calculations after adsorbing the molecule into the zeolite NaY or AgY having “hard” sodium ions or “soft” silver ions. Since the diphenylketene has such a specific structure that a carbonyl group (a hard base) is accumulated by a carbon-carbon double bond (a soft π base), which is conjugated with two benzene rings (soft π bases), it is possible for the diphenylketene to adopt multicoordination modes to the different metal ions in the zeolite. As a result, the coordination modes of diphenylketene adsorbed in the NaY and AgY were identified, and specific coordination behaviors in the zeolite’s supercages were classified depending on the hard or soft metal characters: The C=O and phenyl coordination modes to Na+ in NaY prevail, while the C=C and phenyl coordination to Ag+ in AgY is favored.

Free Research Field

触媒化学

Academic Significance and Societal Importance of the Research Achievements

ナノメートルサイズの珪酸塩鉱物がもつ微小空間は，地球誕生後の化学進化の時代に，生命誕生に必要な化学物質の誕生に，重要な場として働いていたと考えられている．現代の有機合成化学においても，天然鉱物がもつ固有の微小空間が，従来のフラスコを用いた合成法よりも，しばしば効率良く化学合成を推進する場となることが多く見出されている．本研究は，鉱物のもつ特有の微小空洞の中での有機物の捕らわれ方を明らかにしたものである．