Takeaki Iwamoto

X-ray analysis of the first trigermaallene (3) and 1,3-digermasilaallene (4) revealed that the trimetallaallene skeletons are not linear but significantly bent, similarly to the corresponding trisilaallene 2. In contrast to 2, no dynamic disorder was observed for 3 and 4.

The first dialkyl-substituted silicon-chalcogen doubly bonded compounds [R2Si=X; R2=1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl, X = S (4), Se (5), and Te (6)]were synthesized by the reactions of an isolable dialkylsilylene R2Si: (3) with phosphine sulfide, elemental selenium, and elemental tellurium, respectively. Systematic changes of characteristics of silicon-chalcogen double bonds are elucidated by X-ray analysis, UV-vis spectroscopy, and DFT calculations. In the solid state, the unsatu

In contrast to carbon, silicon does not readily form double bonds, and compounds containing silicon-silicon double bonds can usually be stabilized only by protection with bulky substituents. We have isolated a silicon analog of spiropentadiene 1, a carbon double-ring compound that has not been isolated to date. In the crystal structure of tetrakis[tri(t-butyldimethylsilyl)silyl]spiropentasiladiene 2, a substantial deviation from the perpendicular arrangement of the two rings is observed, and the

The reactions of stable cyclic dialkylgermylene 2 and dialkylstannylene 3 with 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) radical (2 equiv) gave the corresponding 1:2 adducts 4 and 5, respectively, which were characterized by NMR, MS, and X-ray analyses. The kinetics of the stepwise addition of two TEMPO molecules to germylene 2 revealed that the initial addition of TEMPO to 2 was 1010 times slower than the second TEMPO addition to the resulting germyl radical. The origin of the rate differenc

1-Naphthyl-, 9-phenanthryl-, and 9-anthryl-substituted trialkyldisilenes 1-3 were synthesized as the first stable disilenes with single polycyclic aromatic substituents, allowing elucidation of the unprecedented intramolecular charge transfer interaction between disilene pi and aromatic pi systems. Anthryl-substituted disilene 3 having a low-lying pi*(aryl) LUMO showed a distinct ICT absorption band due to the charge transfer from a disilene pi donor to an aromatic pi acceptor.

A crystalline two-coordinate cyclic (alkyl)(amino)silylene (1) was successfully synthesized and isolated. Its ²⁹ Si NMR and UV/Vis spectra indicate that the electronic properties of 1 fall between those of cyclic dialkylsilylenes and diaminosilylenes. At very low temperature, the color of a solution of 1 turned from colorless to yellow, which was monitored by UV/Vis spectroscopy. DFT calculations supported the hypothesis that head-to-head dimers (disilenes) with a very long Si-Si dist

The first stable 2-germadisilaallene was synthesized by the reduction of a 2 ratio 1 mixture of a stable dialkylsilylene and dichlorogermylene-dioxane complex with KC8; the 2-germadisilaallene showed dynamic disorder similar to the corresponding trisilaallene in the solid state.

Despite tremendous efforts to synthesize isolable compounds with an Si=O bond, silicon analogues of ketones that contain an unperturbed Si=O bond have remained elusive for more than 100 years. Herein, we report the synthesis of an isolable silicon analogue of a ketone that exhibits a three-coordinate silicon center and an unperturbed Si=O bond, thus representing the first example of a genuine silanone. Most importantly, this silanone does not require coordination by Lewis bases and acids and/or

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTThe First 1,3-Disilabicyclo[1.1.0]butane with Long-Bridge Silicon−Silicon BondTakeaki Iwamoto, Dongzhu Yin, Chizuko Kabuto, and Mitsuo KiraView Author Information Department of Chemistry Graduate School of Science, Tohoku University Aoba-ku, Sendai, 980-8578, Japan Cite this: J. Am. Chem. Soc. 2001, 123, 50, 12730–12731Publication Date (Web):November 20, 2001Publication History Received9 July 2001Published online20 November 2001Published inissue

A series of dialkylsilylene-group 10 metal complexes (RH2Si)(Me3P)2M (M = Ni, Pd, Pt, RH2 = 1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl) and novel (η6-arene)(dialkylsilylene)nickel complexes (η6-arene)(RH2Si)Ni were synthesized and characterized by NMR spectroscopy and X-ray analysis. The perpendicular geometry around the Si–M bond and the short Si–M distances of (RH2Si)(Me3P)2M complexes indicate the significant back donation from the metal to the silylene ligand.

Four isolable dialkylsilanimines RH2SiNR (R = CH2Ph (5a), Ph (5b), 1-adamantyl (5c) and SiMe3 (5d), where RH2 = 1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl) were synthesized as air-sensitive crystals by the reaction of isolable dialkylsilylene 4 with the corresponding azides. X-ray analysis shows that 5a–5d are base-free silanimines and 5a and 5b have a remarkable bent SiN–R structure, while 5c and 5d have an almost linear structure. Distinct π(SiN)→π*(SiN) and n(N)→π*(SiN) transition bands

The proton abstraction (sila-metalation) of trialkylsilyl-substituted dihydridosilanes with t-BuLi or LDA in THF was found to be a convenient route to the corresponding silyllithiums (RR‘SiHLi; 1a, R, R‘ = t-BuMe2Si; 1b, R, R‘ = Me3Si; 1c, R, R‘ = i-Pr2MeSi; 1d, R = t-BuMe2Si, R‘ = 4-methylphenyl). Hydridosilylithium 1a was isolated as air- and moisture-sensitive, but thermally stable, colorless crystals. X-ray analysis has shown that 1a is dimeric in the solid state, where two lithium atoms bri