Tohoku University · Materials Science
Professor Hisako Hashimoto's research lab specializes in main-group and transition-metal organometallic chemistry, with a focus on the synthesis and reactivity of low-valent main-group element complexes, particularly those involving silicon, germanium, and tin. The lab explores novel bonding motifs such as M≡E (E = Si, Ge, Sn) multiple bonds, agostic interactions, and unique metal-ligand cooperativity in catalytic transformations. Key research directions include the development of silylene and germylene complexes, their reactivity toward small molecules (e.g., nitriles, ketones), and the design of efficient catalytic systems for hydrosilylation and hydrogermylation reactions. The lab combines experimental techniques with DFT calculations to elucidate reaction mechanisms and structural features of reactive intermediates.
Figures are computed from collected data and may differ slightly.
Ring around the RuSi: Abstraction of a pyridine ligand with BPh3 was used to synthesize the silylene complex 1 (see scheme), which reacts with nitriles at room temperature to give silylisocyanide complex 3 by CC bond activation. The structure of key intermediate 2 with an η2-SiH agostic interaction is given along with mechanisms for the formation of 2 and 3.
The germylyne complex 2 was obtained by dehydrogenation of a hydrido (hydrogermylene) complex 1 with mesityl isocyanate on heating. A reaction intermediate 3 was also isolated by a room temperature reaction, which was converted into 2 by heating, with elimination of MesNHCHO. A possible mechanism for the formation of 2 was elucidated by kinetic studies and DFT calculations. The heavier analogues of transition-metal carbyne complexes are attractive synthetic targets for research in fundamental or
The novel μ-iminosilyl complexes Ru2(CO)4(μ-dppm)(μ-SiTol2)(μ-R‘CHNSiTol2) (2) were obtained in high yields during the stoichiometric reactions of a diruthenium complex having Ru−H−Si interactions, {Ru(CO)2(SiTol2H)}2(μ-dppm)(μ-η2:η2-H2SiTol2) (1), with nitriles R‘CN (R‘ = Me, Ph, t-Bu, CHCH2). The catalytic hydrosilylation of various ketones and imines with dihydrosilanes were achieved using 1 as a catalyst. A novel reaction cycle involving the cooperative functions of the two Ru metals is prop
The platinum silyl-substituted η2-disilene complex (Me3P)2Pt[Si(SiMe2(t-Bu))2]2 (4) was synthesized by the reaction of cis-(Me3P)2PtCl2 (5) with 1,2-dilithiotetrakis(tert-butyldimethylsilyl)disilane (6) in THF at −50 °C for 3 h. The X-ray structural analysis revealed that 4 can be regarded as a metalladisilacyclopropane with very weak π-complex character.
Abstract A neutral germylene tungsten complex with W–H and Ge–H bonds was prepared by the reaction of an acetonitrile(methyl)tungsten complex with trihydrogermane at room temperature. X-ray crystal structure analysis and IR study revealed that there is a weak but significant interligand interaction between the germylene and hydrido ligands. The germylene complex reacted with nitriles and ketones to give hydrogermylation products in high yields.
Treatment of pyridine-stabilized silylene complexes [(η(5)-C5 Me4R)(CO)2(H)W=SiH(py)(Tsi)] (R = Me, Et; py = pyridine; Tsi = C(SiMe3)3) with an N-heterocyclic carbene (Me)I(i)Pr (1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) caused deprotonation to afford anionic silylene complexes [(η(5)-C5Me4 R)(CO)2W=SiH(Tsi)][H(Me)I(i)Pr] (R = Me (1-Me); R = Et (1-Et)). Subsequent oxidation of 1-Me and 1-Et with pyridine-N-oxide (1 equiv) gave anionic η(2)-silaaldehydetungsten complexes [(η(5)-C5Me4R)(CO)2
A silyl(silylene) iron complex, Cp*Fe(CO)(SiMes2)SiMe3 (1), which was prepared by the photoreaction of Cp*Fe(CO)2Me (2) with hydrodisilane Mes2MeSiSiMe2H (3), reacted with nitriles RCN (R = Ph, Me) at 80 °C to afford a mixture of a disilanyl isocyanide complex Cp*Fe(CO)(R)(CNSiMe2SiMes2Me) (5a, R = Ph; 5b, R = Me) and a pair of diastereomers of Cp*Fe(CO)(R)(CNSiMesMeSiMesMe2) (6a, R = Ph; 6b, R = Me). The molecular structure of 5a was determined by X-ray crystallography. On the other hand, when
The first η 2 -disilenepalladium complexes were synthesized using two different reactions; the reactions of bis(phosphine)dichloropalladiums with a 1,2-dilithiotetrakis(trialkylsilyl)disilane, which was prepared by the reaction of a stable tetrakis(trialkylsilyl)disilene with lithium (Method A) and the direct reactions of the bis(phosphine)dichloropalladiums with the stable disilene (Method B). Comparison of X-ray structural parameters of the disilenepalladium complexes with those of the corre
Reactions of a neutral silyleneruthenium complex with ketones and aldehydes, and isolation of their agostic intermediates are reported, where an alpha-H abstraction or hydrosilylation of the carbonyl compounds occurs depending on the substituents of the substrates.
Novel disilene-iron complexes [(E)- (1E) and (Z)-(eta2-R3SiClSi=SiClSiR3)Fe(CO)4 (1Z), SiR3 = tBu2MeSi] were synthesized by the reaction of the corresponding tetrachlorodisilane with an excess amount of K2Fe(CO)4, and the structures of 1E and 1Z were determined by X-ray crystallography. These complexes constitute not only the first transition-metal complexes with E,Z-isomerism but also the first complexes with halogen-substituted disilene ligands. The initial formation of 1Z during the synthetic
A germylyne complex Cp*(CO)2W≡GeC(SiMe3)3 (1) reacted with alcohols to give simple nucleophilic addition products, while 1 reacted with two molecules of arylaldehydes consecutively to give base-stabilised alkoxy(germylene) complexes via C-H bond activation and hydrogermylation.
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTClusters as Ligands. Coordination of an Electronically Unsaturated Chromaborane to an Iron Tricarbonyl FragmentHisako Hashimoto, Maoyu Shang, and Thomas P. FehlnerView Author Information Department of Chemistry and Biochemistry University of Notre Dame, Notre Dame, Indiana 46556Cite this: J. Am. Chem. Soc. 1996, 118, 34, 8164–8165Publication Date (Web):August 28, 1996Publication History Received15 May 1996Published online28 August 1996Published i
The reaction of the electronically unsaturated Cp*2Cr2B4H8 (1; Cp* = η5-C5Me5) cluster with CS2 yields the saturated Cp*2Cr2(CH2S2B4H6) (3) cluster in better than 90% isolated yield. Both solution spectroscopic and solid-state crystallographic data show that 3, with C2 point symmetry, contains an intracluster bridging methanedithiolato H2CS2 ligand in which the S atoms of the ligand have replaced two transoid BHCr bridging hydrogens in 1, which in turn have added to the carbon atom. The three co
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