Search

Tetrasilabicyclo[1.1.0]but-1(3)-enes, compounds containing an Si=Si double bond with an inverted geometry, have recently emerged as a new class of stable π-electron systems of silicon. Herein, we r...

Due to an intrinsically polar π-bond with a narrow π-π* gap, silenes (silicon-carbon doubly bonded compounds) should receive remarkable attention as a member of π-conjugation units. We report herei...

A cyclic (alkyl)(amino)bromoborane (CAABBr) was synthesized by a reaction of the corresponding hydroborane with bromine in the presence of triethylamine. Reduction of the resulting CAABBr with Li p...

We examined a virtual simulation scheme for reaction condition optimization using machine learning for a small number of experiments with nine reaction conditions, consisting of five continuous and...

Two-coordinate group-15 element centered radicals that bear a lone pair and an unpaired electron on the same group-15 atoms have received much attention in group-15 element chemistry. We previously synthesized an isolable dialkylphosphinyl radical, 2,2,5,5-tetrakis(trimethylsilyl)-1-phosphacyclopentane-1-yl (1P) and its antimony and bismuth analogues (stibinyl radical 1Sb and bismuthinyl radical 1Bi) as persistent radicals. We report herein (1) synthesis of an isolable cyclic dialkylarsinyl radical 1As that exists in the radical form both in solution and in the solid state and (2) comprehensive study of a series of neutral two-coordinate pnictogen-centered radicals (1P, 1As, 1Sb, 1Bi) including UV-vis spectra, redox properties, and reactions.

A spiro-type cyclotrisilene was synthesized by the novel Si–Si coupling reaction of a disilenide and a base-adduct of bromosilylene and characterized by a combination of spectroscopic and crystallo...

Dialkyl(potassio)silyl radical 6a[K(18-crown-6)] and dialkylsilylene radical anion 6b[K([2.2.2]cryptand)] were synthesized by the one-electron reduction of dialkylsilylene 5 and characterized by X-ray diffractional analysis and EPR spectroscopy. The structural change from 5 to 6b upon the one-electron reduction can be explained by reduced σ(Si–C) → 3p(Siα) orbital interactions.

1,2-Dihalosilene is a hitherto unknown but potentially useful functionalizable compound for new silenes and silicon–carbon triply bonded species. We successfully generate 1,2-dibromosilene 1 by the reaction of tetrabromo derivative 2 with BuLi. The formation of 1 is confirmed by NMR studies and trapping experiments. Silene 1 survives under −80 °C, but 1 thermally isomerizes to silacyclohexane 6 via a 1,2-bromine shift to form bis(silyl)carbene 11 and the subsequent intramolecular C–H insertion.

Reactions of a stable dialkylphosphinyl radical, 2,2,5,5-tetrakis(trimethylsilyl)-1-phosphacyclopentane-1-yl (1) with BH3-Lewis base (LB) adducts [BH3(LB)] provided hydrophosphine 3, hydrophosphine-borane complex 4, and μ-phosphinodiborane(6) 5 as detectable products via hydrogen abstraction. Theoretical studies revealed that B–H bonds in BH3 become considerably weaker upon coordination of 1, which reflected in facile hydrogen abstraction from phosphinyl radical-BH3 complex.

Ferrocenyl-substituted bicyclo[1.1.1]pentasilanes 1, 2, and 3 were synthesized by the reactions of bromo-substituted bicyclo[1.1.1]pentasilanes with lithioferrocene. Significant interactions betwee...

In the last decade, several stable silicon compounds with nonclassical inverted geometry around silicon atoms have been synthesized. Their unusual structures, bonding, and reactivity have been inve...

A new carbon family with a prism structure has been found by quantum chemical calculations. The prism-C20 has a D10h structure with double-layered decagonal rings connected each other by ten vertic...

Reaction of stable phosphinyl radical 1a with AZADO gave aminoxyphosphine 3 as the primary product by selective radical coupling at −40 °C. Compound 3 decomposed to phosphorane 4, silyl phosphinate...

Benzo[b]thiophene, 4,7-dibromobenzo[b]thiophene, thieno[3,2-b]thiophene, and 3-bromothieno[3,2-b]thiophene were prepared by AuCl-catalyzed cyclization of (t-butylsulfanyl)(ethynyl)benzenes or (t-bu...

Two-coordinate dialkylsilylene–coinage metal complexes 3+·TPFPB− (Cu) and 4+·TPFPB− (Ag) were synthesized as the first dialkylsilylene–copper complex and the first silylene–silver complex, respecti...

In this account, the synthesis, structure, and reactions of cyclic, spiro-conjugated, and cumulative silicon-silicon doubly-bonded compounds are described. Photochemical and thermal interconversion among Si 4 R 6 isomers including cyclotetrasilene 1, cyclotrisilene 2, and bicyclo[1.1.0]tetrasilane 7 occur without apparent participation of the corresponding tetrasila-1,3-diene, in contrast to the related interconversion among C 4 H 6 isomers. Whereas parent spiropentadiene, the simplest spiroconjugation system, is known to survive only below -100 °C, spiropentasiladiene 3 is thermally very stable and shows remarkable spiroconjugation between the two ring π systems. The skeleton of isolable tri-silaallene 4, the first stable silicon compound with tetracoordinate divalent (formally sp-hybridized) silicon atom, is not linear but remarkably bent. The considerable conjugation between two cumulative Si=Si double bonds was observed. The structural feature of 4 is quite different from that of carbon-based allenes having linear structure without conjugation between two π-bonds.

Versatile reaction modes of tetrasilyldisilenes with various reagents have been disclosed. Typically, tetrakis(t-butyldimethylsilyl)disilene 1b reacts with 1-alkenes and a 1-alkyne having allylic hydrogens to afford the corresponding ene-addition products, while a reaction of 1b with styrene gives the [2+2] cycloaddition product. In contrast to tetra-t-butyldisilene and tetramesityldisilene, a reaction of 1b with a 1,3-butadiene gives quantitatively the [4+2] cycloaddition product. In accord with the biradical nature of disilene as predicted theoretically, tetrasilyldisilene 1b reacts with haloalkanes to provide the corresponding 2,3-dichlorotetrasilane or 2-alkyl-3-chlorotetrasilane probably via radical mechanisms. Facile nucleophilic additions of water, methanol, and methyllithium to 1b are indicative of the high electrophilicity of 1b.

1,3-Digermabicyclo[1.1.0]butane 2 was synthesized as yellow crystals. The molecular structure, 13C NMR and UV–vis spectra, and theoretical calculations have revealed that 2 is a typical long bond i...

The first anti-tricyclo[3.1.0.02,4]hexasilane 1 was synthesized as pale yellow crystals. Irradiation (λ > 370 nm) of 1 gave its skeletal isomer, tricyclo[2.2.0.02,5]hexasilane 2, in 80% yield. The ...

A novel dinuclear palladium complex with one bridging dialkylsilylene ligand 6 was synthesized by the reaction of isolable dialkylsilylene 7 (R2Si:) with two equiv of bis(tricyclohexyl)phosphinepal...

1,2-Dilithiotetrakis(trialkylsilyl)disilanes [(R3Si)2SiLi]2 (R3Si = t-BuMe2Si and i-Pr2MeSi) were prepared as stable off-white powder by the reduction of the corresponding tetrakis(trialkylsilyl)disilenes with lithium in THF. The 1,2-dilithiodisilanes reacted with water, iodomethane, and chlorosilanes to give the corresponding disubstituted products in high yields.

Thermal isomerization of hexakis(t-butyldimethylsilyl)tetrasilabicylo[1.1.0]butane (2) to the corresponding tetrasilacyclobutene (1) as well as photochemical isomerization of 1 to 2 was confirmed using substituent-labeling experiments to proceed via 1,2-silyl-migration instead of skeletal isomerization.