This account describes recent progress (>2006) in the synthesis and structural characterization of isolable N-heterocyclic silylenes (NHSi's) their fascinating reactivities with respect to an emergent topic main-group chemistry: metal-free small-molecule activation. Since seminal discovery stable silicon analogues nucleophilic Wanzlick−Arduengo-type carbenes 1994, new types NHSi's have emerged unique electronic features strikingly different reactivities. Among them, first zwitterionic...

King of donor: The chelating bis(carbene) 1 enabled the synthesis new silyliumylidene salt 2. This can be dechlorinated with sodium naphthalenide to give first cyclic siladicarbene 3, which bears a single Si0 atom strikingly high basicity. small C-Si-C angle 89.1° and average CSi distance 1.869 Å are consistent results from theoretical calculations, revealed that 3 is best described as silylone. As service our authors readers, this journal provides supporting information supplied by...

With the fast development of cell therapy, there has been a shift toward injectable hydrogels as carriers that can overcome current limitations in therapy. However, are prone to damage during use, inducing apoptosis. Therefore, this study was carried out develop an and self-healing hydrogel based on chondroitin sulfate multiple aldehyde (CSMA) N-succinyl-chitosan (SC). By varying CSMA SC ratio, stiffness, water content, kinetics gelation could be controlled. Gelation readily occurred at...

By employing the chelate dicarbene 1, new chlorogermyliumylidene complex 2 could be synthesized and isolated in 95% yield. Dechlorination of with sodium naphthalenide furnishes unique cyclic germadicarbene 3 which 45% Compound is first isolable Ge(0) a single germanium atom stabilized by dicarbene. Its molecular structure accordance DFT calculations underline peculiar electronic two lone pairs electrons at Ge atom.

The unique isolable silanone complex 3 has been synthesized and isolated in 94% yield by the remarkably facile oxygenation of NHC-silylene precursor 2 featuring a Si(II) atom with unusually high nucleophilicity. latter is easily accessible reaction stable silylene 1 corresponding N-heterocyclic carbene (NHC) at -60 degrees C. short Si=O distance 1.541(2) A suggests presence betaine-like pi system balanced electrostatics.

Silylene bites twice in the first insertion of a silylene into PP bond P4 tetrahedron. Reaction 1 (see scheme; R=2,6-diisopropylphenyl) with white phosphorus at ambient temperature gives 2 tricyclic SiP4 core. The electronic situation favors second equivalent skeleton, affording novel strained silaphosphane 3 Si2P4 Supporting information for this article is available on WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z701203_s.pdf or from author. Please note: publisher not...

The first silicon analogue of a carbonic ester, compound 2, and the novel cyclodisiloxane 4 have been synthesized by remarkably clean mono- dioxygenation reactions stable siloxysilylene 1 with N2O (CO2) O2, respectively. Ester 2 represents unique donor-supported Si═O complex an intriguing thermal stability up to 200 °C. addition MeOH at bond in furnishes corresponding adduct 3.

Abstract A series of N‐heterocyclic carbene‐stabilized silanechalcogenones 2 a , b (SiO), 3 (SiS), 4 (SiSe), and 5 (SiTe) are described. The silanone complexes were prepared by facile oxygenation the carbene–silylene adducts 1 with N O, whereas their heavier congeners synthesized gentle chalcogenation equimolar amounts elemental sulfur, selenium, tellurium, respectively. These novel compounds have been isolated in crystalline form high yields fully characterized variety techniques...

Monoatomic zerovalent main-group element complexes emerged very recently and attracted increasing attention of both theoretical experimental chemists. In particular, silicon their congeners (metallylones) stabilized by neutral Lewis donors are significant importance not only because intriguing electronic structure but also they can serve as useful building blocks for novel chemical species. Featuring four valence electrons two lone pairs at the central atoms, such may form donor-acceptor...

Abstract The first 4π‐electron resonance‐stabilized 1,3‐digerma‐2,4‐diphosphacyclobutadiene [L H 2 Ge P ] 4 (L =CH[CHNDipp] Dipp=2,6‐ i Pr C 6 3 ) with four‐coordinate germanium supported by a β‐diketiminate ligand and two‐coordinate phosphorus atoms has been synthesized from the unprecedented phosphaketenyl‐functionalized N‐heterocyclic germylene Ge‐P=C=O] prepared salt‐metathesis reaction of sodium phosphaethynolate (P≡C−ONa) corresponding chlorogermylene GeCl] 1 . Under UV/Vis light...

Abstract The first zwitterionic borata‐bis(NHC)‐stabilized phosphaketenyl germyliumylidene [(L 2 (O=C=P)Ge:] (L =( p ‐tolyl) B[1‐(1‐adamantyl)‐3‐yl‐2‐ylidene] ) has been synthesized by salt‐metathesis reaction of [L (Cl)Ge:] 1 with sodium phosphaethynolate [(dioxane) n NaOCP]. Unexpectedly, its exposure to UV light affords, after reductive elimination the entire PCO group, unprecedented Ge‐GeL ] complex 3 in 54 % yields bearing Ge 2+ ion oxidation state +1. In addition,...

A monatomic zerovalent silicon(0) complex ("silylone") stabilized by the chelating bis(silylenyl)-ortho-carborane ligand, 1,2-(LSi)2-1,2-C2B10H10 [L = PhC(NtBu)2], has been synthesized from redox reaction of dipotassium bis(silylenyl)-nido-carboranate salt, 1,2-(LSi)2-1,2-C2B10H10K2, and NHC-SiCl2 (NHC {[HCN(2,6-iPr2C6H3)]2C:}). Markedly different previous examples, this silylone undergoes reduction due to closo-C2B10 cluster backbone, which is prone accept up two electrons form cage-opened...

ConspectusSilylenes are divalent silicon species with an unoccupied 3p orbital and one lone pair of electrons at the SiII center. Owing to excellent σ-donating ability amidinato-based silylenes, which stems from intramolecular imino-N donor interaction vacant atom, N-heterocyclic amidinato bis(silylenes) [bis(NHSi)s] can serve as versatile strong donating ligands for cooperative stabilization central atoms in unusually low oxidation states. Herein, we present our recent achievement on...

The new silanone complex 3 is accessible in 82% yield and capable of undergoing addition ammonia under mild conditions, yielding the sila-hemiaminal 4 and, at same time, its unique tautomer 5, first silanoic amide. unexpected formation due to presence basic exocyclic methylene group C(3)N(2) ligand backbone. Strikingly, tautomers 5 are equilibrium solution can be cocrystallized benzene or THF solutions having a SiOH...O=Si hydrogen bond as confirmed by single-crystal X-ray diffraction analysis.

The unique isolable N-heterocyclic carbene (NHC)→germanone complexes 3a and 3b were synthesised structurally characterised, starting from the corresponding NHC–germylene precursors 2a 2b through straightforward oxygenation with N2O.

Donor–acceptor trumps: The chlorosilyliumylidene salt 2 with a three-coordinate silicon(II) atom is accessible through ligand exchange between NHCSiCl2 and the electron-rich bis(ylide) 1. cation in represents donor-stabilized form of elusive [ClSi:] could be fully characterized, including X-ray diffraction analysis. Oxidation elemental sulfur furnished 3 as sole product.

Abstract The unusual reactivity of the newly synthesized β‐diketiminato cobalt(I) complexes, [(L Dep Co) 2 ] ( a , L =CH[C(Me)N(2,6‐Et C 6 H 3 )] ) and [L Dipp Co ⋅ toluene] b =CH[CHN(2,6‐ i Pr ), toward white phosphorus was investigated, affording first complexes (μ :η 4 ,η ‐P bearing neutral cyclo‐P ligand with rectangular‐planar structure. redox chemistry studied by cyclic voltammetry their chemical reduction one molar equivalent potassium graphite led to isolation )][K(dme) )....

Employing the potassium salt of monoanionic bis(NHC)borate 1 (NHC = N-Heterocyclic Carbene) enables synthesis and isolation bis(NHC)borate-stabilized chlorogermyliumylidene precursor 2 in 61% yield. A Cl/H exchange reaction using trisec.-butylborhydride as a hydride source leads to first germyliumylidene [HGe:+] complex 3 91% The Ge(II)–H bond latter compound has an unexpected reactivity shown by with potential scavenger [Ph3C]+[B(C6F5)4]−, furnishing corresponding HGe: → CPh3 cation ion...

The unexpected reactivity of the o-carborane supported bis-silylene [(LSi:)C]2B10H101 {L= PhC(tBuN)2} towards carbon monoxide and 2,6-dimethylphenyl isocyanide is reported. While reaction 1 with CO leads selectively to novel head-to-head coupling C-O cleavage product 2 from two molecules four CO, affords solely : molar head-to-tail 3 a Si[double bond, length as m-dash]C bond.