Amidinato silylene-based inorganic aromatic rings.

Aromaticity is a key concept that underpins the behavior and applications of a wide range of chemical compounds. Its impact on stability, reactivity, biological functions, material properties, and environmental persistence underscores the importance of understanding and harnessing aromaticity in chemistry and materials sciences. We have been pioneers in the field of silylene chemistry and recently, our silylene molecules have been used to synthesize several inorganic aromatic ring compounds.

Phosphasilene mediated CO activation and deoxygenative homo coupling of CO molecules in reactions with metal carbonyls.

Herein, we report the synthesis of a new sterically demanding hyper-coordinate phosphasilene (Mes*PSi(SiMe)(PhC(N Bu)) (1) and its unprecedented reactivity with metal carbonyls (M = Fe, Mo, W). The reaction of 1 with Fe(CO) involves the deoxygenative homocoupling of two CO molecules, forming a rare ketene (μ-CCO) inserted Fe complex 2. Contrastingly, reactions with M(CO) (M = Mo, W) entail the deoxygenated activation of one CO molecule, with the second CO molecule being trapped between Si and P atoms.

Recent progress in transition metal complexes featuring silylene as ligands.

Silylenes, divalent silicon(II) compounds, once considered highly reactive and transient species, are now widely employed as stable synthons in main-group and coordination chemistry for myriad applications. The synthesis of stable silylenes represents a major breakthrough, which led to extensive exploration of silylenes in stabilizing low-valent main-group elements and as versatile ligands in coordination chemistry and catalysis. In recent years, the exploration of transition metal complexes stabilized with silylene ligands has captivated significant research attention.

Preparation of a high-coordinated-silicon-centered spiro-cyclic compound.

Silicon compounds containing silicon-silicon bond with a variety of unusual oxidation states are quite important, because their high reactivity leads to the formation of a variety of silicon compounds. The isolation of such compounds with unusual oxidation states requires a resilient synthetic strategy. Herein, we report the synthesis of a silicon based spirocyclic compound containing a hyper-valent silicon atom and a silicon-silicon bond.

Synthesis, Reactivity, and Complexation with Fe(0) of a Tight-bite Bis(N-heterocyclic silylene).

The synthesis, reactivity, and complexation with Fe(0) precursor of a tight-bite bis(N-heterocyclic silylene) (bis(NHSi)) ligand 1 are reported. The reaction of 1 with p-toluidine led to the activation of both N-H bonds across Si(II) atoms to afford a four-membered heterocyclic cyclodisilazane 2, with hydride substituents attached to five-coordinate Si atoms. A 1 : 2 reaction of 1 with Fe(CO) led to an intriguing dinuclear complex 3 featuring a five-membered (N-Si-Fe-Fe-Si) ring with a Fe-Fe bond distance of 2.

Stabilization of NH- Group Adjacent to Naked Silicon(II) Atom in Base Stabilized Aminosilylenes.

Aminosilylene, comprising reactive NH- and Si(II) sites next to each other, is an intriguing class of compounds due to its ability to show diverse reactivity. However, stabilizing the reactive NH- group next to the free Si(II) atom is challenging and has not yet been achieved. Herein, we report the first examples of base stabilized free aminosilylenes Ar*NHSi(PhC(N Bu) ) (1 a) and Mes*NHSi(PhC(N Bu) ) (1 b) (Ar*=2,6-dibenzhydryl-4-methylphenyl and Mes*=2,4,6-tri-tert-butylphenyl), tolerating a NH- group next to the naked Si(II) atom.

A Neutral Planar Four-Membered SiB 2π-Aromatic Ring.

The synthesis of the compound is reported. This unique ring has been synthesized from a simple and straightforward reaction of amidinato-silylene with dichlorophenylborane, followed by the reduction with KC in THF. Compound has been fully characterized by single-crystal X-ray diffraction (SC-XRD), NMR spectroscopy, and mass spectrometry.

Preparation of a Compound with a Si -Si -Si Bonding Arrangement.

Herein, we report the synthesis of a rare bis-silylene, 1, in which two Si atoms are bridged by a Si atom. Compound 1 contains an unusual Si -Si -Si bonding arrangement with Si -Si bond distances of 2.4212(8) and 2.

Geometrically Compelled Silicon(II)/Silicon(IV) Donor-Acceptor Interaction Enables the Enamination of Nitriles.

Discovering new bonding scenarios and subsequently exploring the reactivity contribute substantially to advance the main group element chemistry. Herein, we report on the isolation and characterization of an intriguing class of the hydrido-benzosiloles 2-4. These compounds exhibit a side arm of the amidinatosilylenyl group, featuring unidirectional silicon(II)/silicon(IV) donor-acceptor interaction on account of the geometric constraint.

Interaction of germanium analogue of organic isonitrile with Cu(I) imide in side-on mode.

[NHC → GeN(Ar)CuNAr], the formal adduct of germanium analogue of organic isonitrile [GeNAr] with Cu(I) imide [(CuNAr)] (Ar = 2,6-PrCH) was prepared from the N-heterocyclic carbene (NHC) stabilized acyclic germylene Ge[N(H)Ar] by reacting with two equivalents of BuLi and CuCl(PPh). As elucidated by X-ray crystal structural characterization, the two separated [GeNAr] moieties interacted with [(CuNAr)] core in the side-on mode.

Synthesis and Characterization of Substituted Phosphasilenes and its Rare Homologue Stibasilene >Si=Sb.

Herein we report the reduction of R-EX (E=P, Sb) with two equivalents of KC in the presence of silylene (LSiR; L=PhC(NtBu) ) to give Trip-P=SiL(C H PPh ) (1), Ph-P=(tBu)SiL (2) and Ph-Sb=(tBu)SiL (3). The last (3) belongs to a new class of heavier analogues of Schiff bases (>C=N-), containing a formal >Si=Sb- double bond. The theoretical calculations suggest that lone pairs on the dicoordinated group-15 centers are stabilized by hyperconjugative interactions resulting in pseudo-Si-P/Si-Sb multiple bonds which are highly reactive as indicated by the high first and second proton affinities.

A Neutral Borylene and its Conversion to a Radical by Selective Hydrogen Transfer.

A successful selective reduction of XB-Tip (Tip = 1,3,5-Pr-CH, X = I, Br) with KC and Mg metal, respectively, in the presence of a hybrid ligand (CH(PPh)LSi) leads to a stable low-valent five-membered ring as a boryl radical [CH(PPh)LSiBTip][Br] () and neutral borylene [CH(PPh)LSiBTip] (). Compound reacts with 1,4-cyclohexadiene, resulting in hydrogen abstraction to afford the radical [CH(PPh)LSiB(H)Tip] (). Quantum chemical studies reveal that compound is a B-centered radical, and compound is a phosphane and silylene stabilized neutral borylene in a trigonal planar environment, whereas compound is an amidinate-centered radical.

[2+4] Cycloaddition Product of an Amidinate Substituted Dialumene with Toluene.

Reduction of LAlI (L=PhC(N Pr C H ) ) with two equivalents of KC in toluene affords the [2+4]cycloaddition product of a dialumene with toluene. The mechanism for the formation of product complex was investigated using density functional theory (DFT) methods.

One silicon atom of bis(silylene) functions as a selective Lewis base under adduct formation with a Lewis acid.

Herein, we describe the facile and selective one-pot synthetic route to silylene-aluminum and silylene-gallium adducts. Reduction of silylene LSiCl (L = PhC(NBu)) with KC in the presence of bulky and sterically hindered cyclopentadienyl aluminum Cp'''AlCl (Cp''' = 1,2,4-BuCH) and gallium [η-Cp'''Ga(μ-Cl)Cl] to afford the Lewis acid-base adducts η-Cp'''M(Cl) ← Si(L)-SiL (M = Al, 1; M = Ga, 3). To confirm the formation of the Lewis acid-base adduct, the bis(silylene) LSi(I)-Si(I)L reacts with Cp'''AlI to form η-Cp'''Al(I) ← Si(L)-SiL (2).

Reactivity of Silylene with Gallium- and Boron Trihalide at Reductive Conditions Resulting in Unforeseen Products.

Herein, we report a one-pot reaction of gallium and boron halides with potassium graphite in the presence of benzamidinate stabilized silylene LSi-R, (L=PhC(N Bu) ). The reaction of LSiCl with an equivalent amount of GaI in the presence of KC leads to the direct substitution of one chloride group by gallium diiodide simultaneously additional coordination of silylene resulted in L(Cl)Si→GaI -Si(L)→GaI (1). In compound 1, the structure comprises two differently coordinated gallium atoms where one gallium presents between two silylenes and the other gallium is only coordinated by one silylene.

Compounds with Alternating Single and Double Bonds of Antimony and Silicon; Isoelectronic to Ethane-1,2-diimine.

We present an approach for preparing chain-type unsaturated molecules with low oxidation state Si(I) and Sb(I) supported by amidinato ligands that exploit to generate heavy analogues of ethane 1,2-diimine. The reduction of antimony dihalide (R-SbCl) with KC in the presence of silylene chloride afforded L─(Cl)Si═Sb─Tip () and L()Si═Sb─Ph (), respectively. Compounds and further undergo reduction with KC to produce Tip─Sb═LSi─LSi═Sb─Tip () and Ph─Sb═LSi─LSi═Sb─Ph ().

Reactions of diphosphine-stabilized Os clusters with triphenylantimony: syntheses and structures of new antimony-containing Os clusters Sb-Ph bond cleavage.

The reactivity of the trimetallic clusters [Os(CO)(μ-dppm)] [dppm = bis(diphenylphosphino)methane] and [HOs(CO){μ-PhPCHPPh(CH-μ,σ)}] with triphenylantimony (SbPh) has been examined. [Os(CO)(μ-dppm)] reacts with SbPh in refluxing toluene to yield three new triosmium clusters [Os(CO)(SbPh)(μ-dppm)] (1), [HOs(CO)(SbPh){μ-PhPCHPPh(CH-μ,σ)}] (2), and [HOs(CO)(SbPh)(μ-CH)(μ-SbPh)(μ-dppm)] (3). [HOs(CO){μ-PhPCHPPh(CH-μ,σ)}] reacts with SbPh (excess) at room temperature to afford [Os(CO)(SbPh)(η-Ph)(μ-SbPh)(μ-dppm)] (4) as the sole product.

Coordination and Stabilization of a Lithium Ion with a Silylene.

Herein, we report the stabilization of lithium-ion as the source of lithium to use as a trans-metalation reagent [{PhC(N Bu) Si( Bu)Li} I( BuN) CPh] (1). The reaction of 3 equivalents of the LSi Bu (L=PhC(N Bu) ) and lithium iodide at low temperature leads to a silylene stabilized lithium-ion with an additional coordination of amidinate ligand. Compound 1 shows two four membered and one six membered ring as confirmed by QTAIM calculations.

Insertion Reaction of MeSiN with Bis(germylene).

Herein, we describe the redox reaction of bis(germylene) PhC(NBu)Ge-Ge(NBu)CPh with different equivalents of MeSiN affording two distinct products. The reaction of MeSiN with bis-germylene in a 1:1 molar ratio results in compound at -78 °C; however, treatment of bis-germylene with a 2.1 equiv of MeSiN at room temperature results in compound .

A neutral vicinal silylene/phosphane supported six-membered CPSiAu ring and a silver(I) complex.

This work presents the different coordination nature of the bidentate ligand towards gold and silver complexes. The reaction of 1 with AuClSMe in dichloromethane resulted in two gold atoms containing six-membered ring PhC(NBu)Si-Au⋯Au-PPhCH (2). Compound 2 exhibits intramolecular aurophilic interaction (2.

Deoxygenating Reduction of CO by [Cp*Al] to Form a (AlOC) Cluster Featuring Two Ketene Moieties.

Herein we report that the reaction of the low-valent aluminum(I) species [Cp*Al] (Cp* = pentamethylcyclopentadienyl) with CO exhibits complete cleavages of the C═O bonds. The deoxygenating reduction reaction of [Cp*Al] with CO at 120 °C afforded [(Cp*)AlOC(CO)] (), which featured two stacked (AlOC) units and two C═C═O ketene moieties. Moreover, the isoelectronic analogues of diimine and isothiocyanate with CO were also investigated, and the reactions of [Cp*Al] with Dipp*-N═C═N-Dipp* and Dipp-C═N═S [Dipp* = 2,6-bis(diphenylmethyl)-4--butylphenyl; Dipp = 2,6-diisopropylphenyl] afforded dialuminylimine () and tetrameric [Cp*AlS] (), respectively.

Excellent yield of a variety of silicon-boron radicals and their reactivity.

Herein we report stable silicon-boron radicals of composition LSi(NMe)-B(Br)Tip (1), LSi(NMe)-B(I)Tip (2) LSi(Bu)-B(I)Tip (3) [L = PhC(NBu)]. They were prepared in high yield using a one pot reaction of LSiR, XBTip and KC in a 1 : 1 : 1 molar ratio (R = Bu, NMe; X = Br, I). The reaction of the silicon-boron radical with Br and Se affords the dihalogenated compound LSi(Bu)-B(Br)Tip (4) and oxidative addition product LSi(Bu)Se (5).

Synthesis, Characterization, and Reaction of Digermylenes.

A series of digermylenes R(EGeL) (L=CH[C(Me)N(Ar)] , Ar=2,6-iPr C H ; E=O, R=1,3-C H (1), 1,4-C H (2), Me C(CH ) (3); E=NH, R=1,4-C H (4), 1,4-C H (5); E=C(O)O, R=1,3-C H (6)) were synthesized by the reactions of L'Ge (L'=HC[C(CH )N(Ar)]C(Me)N(Ar), Ar=2,6-iPr C H ) with selected diphenols, diol, diamines, and o-/m-phthalic acids, respectively. Treatment of digermylene 1,3-C H (OGeL) (1) with sulfur, selenium and CuX (X=Cl, Br, I) led to the formation of 1,3-C H [OGe(S)L] (8), 1,3-C H [OGe(Se)L] (9), and (CuX) [1,3-C H (OGeL) ] (X=Cl (10), Br (11), I (12)), respectively. The obtained products were characterized by melting point, elemental analysis, FT-IR, H and C NMR spectroscopy, and single-crystal X-ray diffraction.

Organoaluminum hydrides catalyzed hydroboration of carbonates, esters, carboxylic acids, and carbon dioxide.

The reductive functionalization of the CO unit of carbonates, carboxylic acids, esters, and CO, respectively has received great attention since its introduction. This method is often used industrially for the synthesis of high value-added energy products in chemistry. This opens up a new way forward to reduce greenhouse gases and the consumption of traditional energy sources.

A Carbene-Stabilized Boryl-Phosphinidene.

Herein, the synthesis and characterization of the carbene-stabilized boryl phosphinidenes 1-3 are reported. Compounds 1-3 are obtained by reacting Me-cAAC=PK (Me -cAAC=dimethyl cyclic(alkyl)(amino)carbene) and dihaloaryl borane in toluene. All three compounds were characterized by X-ray crystallography.