Tokyo Institute of Technology · Materials Science
Professor Yumiko Nakajima's research lab specializes in transition metal-catalyzed organic transformations, with a strong focus on developing efficient, selective, and sustainable catalytic systems for synthetic applications. Key research directions include hydrosilylation and silyl-Heck reactions using nickel and ruthenium complexes, enabling mild and selective C–H and C–X bond functionalization. The lab also explores the reactivity of multimetallic clusters and their role in bond activation, such as N–H and H–H cleavage. Additionally, they investigate the biological relevance of endogenous lipid mediators, such as anandamide, in inflammatory processes, particularly in periodontal disease.
Figures are computed from collected data and may differ slightly.
This review focuses on the recent development of efficient, selective, and cheaper hydrosilylation catalyst systems appearing in the last decade.
Anandamide (AEA) exhibits anti‐inflammatory effects. However, its role in the periodontal field remains unknown. Here, we found that gingival crevicular fluid contained a detectable level of AEA. The cannabinoid receptors CB1 and CB2 were expressed by human gingival fibroblasts (HGFs), and markedly upregulated under pathological conditions. AEA significantly reduced the production of pro‐inflammatory mediators (IL‐6, IL‐8 and MCP‐1) induced by Porphyromonas gingivalis LPS in HGFs, and this effec
More cleavage: The complex [(Cp*Ru)3(μ3-H)2(μ-H)3] (Cp*=η5-C5Me5) promotes NH bond cleavage of ammonia to yield the mono-μ3-imido complex [(Cp*Ru)3(μ3-NH)(μ-H)3] (2), probably via μ-amido complex [(Cp*Ru)3(μ-NH2)(μ-H)4]. Introduction of a triply bridging oxo ligand into the Ru3 core (→1) makes the reaction kinetically and thermodynamically favorable and gives 2 within 1 h at 80 °C.
A strategy of capturing ethylene glycol with dimethyl carbonate in the catalytic methanolysis of polyethylene terephthalate enabled depolymerization at ambient temperature.
Olefin hydrosilylation was attained at room temperature at 0.5 mol% Ni loading by using a series of (salicylaldiminato)methylnickel complexes as catalyst precursors.
A nickel complex/Lewis acid combination effectively catalyzed the direct silyl-Heck reaction of chlorosilanes, which are key raw materials in the organosilicon industry, to give synthetically important alkenylsilane products. Trichlorosilanes, dichlorosilanes, and monochlorosilanes underwent the silyl-Heck reaction to afford the corresponding alkenylsilanes in high yields. In the reactions of dichlorosilanes, a single substitution occurred to give monoalkenylsilanes in a highly selective manner.
Simple nickel salts, bis(acetylacetonato)nickel(<sc>ii</sc>) and its derivatives, catalyzed the hydroboration reactions of aryl and alkyl nitriles with catechol borane<sc>.</sc>
A 15-electron iron complex with a formal Fe(I) center, [FeBr(BPEP)] (BPEP = 2,6-bis(1-phenyl-2-phosphaethenyl)pyridine), was prepared by one-electron reduction of the dibromide precursor [FeBr(2)(BPEP)]. The single-crystal diffraction analysis revealed a distorted trigonal monopyramidal arrangement around the iron center, and SQUID magnetometry established the S = 3/2 ground state. The Mossbauer isomer shift value (delta = 0.59 mm/s) was consistent with a high-spin Fe(I) center of [FeBr(BPEP)].
In this account, our studies on nickel-catalyzed hydrosilylation reactions are described. A series of (salicylaldiminato)methylnickel complexes efficiently catalyze alkene hydrosilylation under ambient reaction conditions. Commercially available Ni(II) salts, Ni(acac)<sub>2</sub> (acac = acetylacetonato) and its derivatives bis(hexafluoroacetylacetonato)nickel(II) and bis (2,2,6,6-tetramethyl-3,5-heptanedionato)nickel(II), also act as versatile hydrosilylation catalyst precursors in the presence
The arene-supported cationic nickel allyl complexes serve as good catalysts for olefin hydrosilylation at room temperature. Detailed mechanistic studies based on experiments and DFT calculations support the novel mechanism, which includes the facile Si-H bond cleavage and Si-C bond formation, assisted by a non-innocent allyl ligand.
2,6-Bis[1-phenyl-2-(2,4,6-tri-tert-butylphenyl)-2-phosphaethenyl]pyridine (BPEP-Ph) reacts with [Ru3(CO)12] or [RuCl(η3-allyl)(CO)3] in toluene at elevated temperatures to afford the three types of PNP-pincer complexes 1–3. The reaction of BPEP-Ph with [Ru3(CO)12] under vacuum forms a mixture of [Ru(CO)2(BPEP-Ph)] (1) and a dicarbonylruthenium(0) complex (2); the latter complex has an unsymmetrical PNP-pincer ligand with 1-phenyl-2-phosphaethenyl and phenyl(benzo[b]phospholan-1-yl)methyl groups
Cu(I) complexes bearing BPEP as a PNP-pincer type phosphaalkene ligand undergo effective bonding interactions with SbF(6)(-) and PF(6)(-) as non-coordinating anions to give [Cu(SbF(6))(BPEP)] and [Cu(2)(BPEP)(2)(μ-PF(6))](+), respectively [BPEP = 2,6-bis(1-phenyl-2-phosphaethenyl)pyridine]. NMR and theoretical studies indicate a reduced anionic charge of the μ-PF(6) ligand, which is induced by the strong π-accepting ability of BPEP.
Polyester fibers, comprising mostly poly(ethylene terephthalate) with high crystalline content, represent the most commonly produced plastic for ubiquitous textiles, and approximately 60 million tons are manufactured annually worldwide. Considering the social issues of mismanaged waste produced from used textile products, there is an urgent demand for sustainable waste polyester fiber recycling methods. We developed a low-temperature, rapid, and efficient depolymerization method for recycling po
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