Takashi Komuro

Preparation of endohedral fullerene containing lithium (Li@C60) and isolation as pure hexafluorophosphate salt ([Li+@C60][PF6−])

A synthetic protocol for endohedral fullerene containing lithium (Li@C60), as well as the synthesis, characterization, and properties of its chemically oxidized derivative [Li+@C60][PF6−] are reported in full. Simultaneous deposition of Li plasma and C60 produces a mixture containing Li@C60 and C60. Strong intermolecular attraction between Li@C60 and C60 has prevented their separation, but this obstacle was surmounted by selective chemical oxidation of Li@C60, which led to the isolation of a substantial amount of pure [Li+@C60][PF6−]. For this purpose, an HPLC technique using an electrolyte in the mobile phase was effective in purifying the ionic metallofullerene. [Li+@C60][PF6−] was stable in air and, compared with [Li+@C60][SbCl6−], was more stable to moisture and various chemicals. [Li+@C60][PF6−] holds promise for practical applications. The spectroscopic data (MS, 7Li and 13C NMR, UV-vis, and IR) and electrochemical data for [Li+@C60][PF6−] are disclosed. In addition, the high electron affinity of [Li+@C60][PF6−] is discussed.

New hydrosilylation reaction of arylacetylene accompanied by C-H bond activation catalyzed by a xantsil ruthenium complex*

A new type of catalytic hydrosilylation of arylalkynes was induced by a 16-electron ruthenium bis(silyl) phosphine complex, resulting in ortho-silylation of the aryl group as well as a hydrogenation of the alkyne CC bond to give an (E)-form of alkene selectively. On the other hand, the same reaction using a related bis(silyl) complex having an η6-toluene ligand instead of the phosphine ligand as a catalyst led to a normal hydrosilylation reaction to afford silylalkene.

Group 6 metal complexes with a hemilabile tridentate xantsil ligand and facile insertion of tBuCN into a W–Si bond [xantsil = (9,9-dimethylxanthene-4,5-diyl)bis(dimethylsilyl)]

The synthesis and characterization of tungsten and molybdenum complexes of the xanthene-based bis(silyl) ligand (xantsil) with a kappa3(Si,Si,O) coordination mode are reported, where an insertion of tBuCN into a tungsten-silicon bond leads to formation of an eta2-iminoacyl complex.

Recombination of an Fe−Si−P Linkage to an Fe−P−Si Linkage through an Isolable Intermediate Phosphasilaferracyclopropane

Phosphasilaferracycle [Cp*(CO)Fe{kappa(2)Si,P-SiMe(2)PPh(2)}], prepared upon irradiation of [Cp*(CO)(2)FeSiMe(2)PPh(2)], was converted to [Cp*(CO)(2)FeP(Ph)SiMe(2)Ph] under mild conditions. The unusual recombination of the iron, silicon, and phosphorus cores could be achieved through a sequence of 1,2- and 1,3-group migrations in an FeSiP system.

Insertion of carbon monoxide into an aldehyde CO double bond induced by an (η3-α-silabenzyl)carbonylmolybdenum complex

Unusual silylcarbonylation of aldehyde through CO insertion into a CO double bond induced by a metal–silicon complex has been discovered: treatment of an (η3-α-silabenzyl)carbonylmolybdenum complex with alkylaldehydes afforded isolable O-silylated Mo–C–O three-membered-ring complexes, and one of them was subsequently converted to an η3-oxaallyl complex at room temperature through CO insertion into the metallacycle C–O bond and incorporation of a CO molecule.

Synthesis and Structures of Alkynylchlorocyclotriphosphazenes and Their Cluster-Forming Reactions with Octacarbonyldicobalt

Cyclotriphosphazenes having p-tolylethynyl and chloro substituents N 3 P 3 {C≡C(pTol)} n Cl 6-n (la: n = 2, 1b: n = 4; p-Tol = p-tolyl) were synthesized by the reaction of hexachlorocyclotriphosphazene (NPCl 2 ) 3 with 2 equiv of LiC=C(p-Tol) in THF. la and 1b were characterized by spectroscopic methods and elemental analyses. The reactions of la and 1b with octacarbonyldicobalt Co 2 (CO) 8 produced cobalt clusters containing tetrahedral C 2 Co 2 (CO) 6 (p-Tol) cluster units; namely, tetranuclear cluster N 3 P 3 {C 2 Co 2 (CO) 6 (p-Tol)} 2 Cl 4 (2) and hexanuclear cluster N 3 P 3 {C 2 Co 2 (CO) 6 (p-Tol)} 3 {C≡C(p-Tol)}Cl 2 (3). Crystal structures of la and 2 were determined by X-ray crystallography.

Diruthenium Complexes with a 1,8-Naphthyridine-based Bis(silyl) Supporting Ligand: Synthesis and Structures of Complexes Containing RuII2(μ-H)2 and RuI2 Cores

We designed a novel naphthyridine-based supporting ligand involving two silyl coordinating moieties at 2,7-positions, t-BuNBSi, for the synthesis of dinuclear metal complexes. Reaction of a ligand precursor t-BuNBSi(H)2 (1) with Ru3(CO)12 gave a di-μ-hydridodiruthenium(II,II) complex (t-BuNBSi)Ru2(μ-H)2(CO)4 (2). Photoirradiation to 2 resulted in formation of a diruthenium(I,I) complex (t-BuNBSi)Ru2(CO)6 (3). The Si–Ru–Ru–Si linkage of 2 takes a zigzag arrangement, whereas that of 3 adopts a roughly linear one.