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.

Reducing hybrid ligand-based alane and chasing aluminium(I): dialane and unusual transient dialumene.

In this work, an alane, [DNIAlH] (1) (DNI = 3,3-dimethyl-2-[2-methyl-2-(2,6-diisopropyl-aniline)ethenyl]-3-indolenine), stabilised by a hybrid ligand was reduced by Jones's Mg(I) ([(BDIMg)]) and Roesky's Al(I) ([BDIAl:]). The resulting dialane compound [{DNI(H)Al}] (2) was characterised using NMR spectroscopy, mass spectrometry, DFT calculations and single-crystal XRD experiments. The reaction of aluminium dihydride [DNIAlH] (1) with [BDIAl:] at high temperatures gives an intramolecular C(sp)-H bond-activated compound 3.

Triplet carbenes with transition-metal substituents.

The extraordinary advances in carbene (R-C-R) chemistry have been fuelled by strategies to stabilize the electronic singlet state via π interactions. In contrast, the lack of similarly efficient approaches to obtain authentic triplet carbenes with appreciable lifetimes beyond cryogenic temperatures hampers their exploitation in synthesis and catalysis. Transition-metal substitution represents a potential strategy, but metallocarbenes (M-C-R) usually represent high-lying excited electronic configurations of the well-established carbyne complexes (M≡C-R).

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.

Boron bis-(4-methylbenzoxazol-2-yl)-methanide complexes.

Boron compounds have attracted the attention of chemists because of their unique catalytic properties and potential wider material applications. Although group 13 metal compounds, which are based on the bis-(benzoxazol-2-yl)-methane system (Box, ({NCOCH}CH)), have been reported in the last several years, boron containing Box compounds were still missing. Now we report their successful syntheses and spectroscopic characterisation in this work.

En Route to a Molecular Terminal Tin Oxide.

In the pursuit of terminal tin chalcogenides, heteroleptic stannylenes bearing terphenyl- and hexamethyldisilazide ligands were reacted with carbodiimides to yield the respective guanidinato complexes. Further supported by quantum chemical calculations, this revealed that the -propyl-substituted derivative provides the maximum steric protection achievable. Oxidation with elemental selenium produced monomeric terminal tin selenides with four-coordinate tin centers.

Correspondence to "Structure of Violet Phosphorus and Its Phosphorene Exfoliation".

The structure described in the publication "Structure of Violet Phosphorus and Its Phosphorene Exfoliation" (Angew. Chem. Int.

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.

A new polymorph of white phosphorus at ambient conditions.

Phosphorus exists in several different allotropes: white, red, violet and black. For industrial and academic applications, white phosphorus is the most important. So far, three polymorphs of white phosphorus, all consisting of P tetrahedra, have been described.

Indium α radiation from a MetalJet X-ray source: the long way to a successful charge-density investigation.

The MetalJet X-ray source provides indium α radiation with a wavelength even shorter than Ag radiation. This paper reports on problematic spectral impurities and presents possible countermeasures so that collection of data with excellent quality up to a high resolution is possible. It is demonstrated that these data can be used in the refinement of a multipole model, the results of which are used for a topological analysis to assess the bonding situation in a sulfur ylide compound.

Indium α radiation from a MetalJet X-ray source: comparison of the Eiger2 CdTe and Photon III detectors.

The MetalJet source makes available new α radiation wavelengths for use in X-ray diffraction experiments. The purpose of this paper is to demonstrate the application of indium α radiation in independent-atom model refinement, as well as approaches using aspherical atomic form factors. The results vary greatly depending on the detector employed, as the energy cut-off of the Eiger2 CdTe provides a solution to a unique energy contamination problem of the MetalJet In radiation, which the Photon III detector cannot provide.

In data we trust: X-ray diffraction experiments for charge density investigations.

A short commentary is given on the paper by Vosegaard et al. [Acta Cryst. (2023), 79, 380-391], which compares charge density models derived from four datasets measured on conventional diffractometers with the results of a high-quality dataset from SPring-8.

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).

Linear and Bent Cp* Si: Reversible Phase Transition of a Key Molecule.

The solid-state structure of decamethylsilicocene Cp* Si with a bent and a linear molecule in the same unit cell was so far considered an exception in relation to the structures of its all-bent heavier analogues Cp* E with E=Ge, Sn, Pb. Here, we present the solution to this conundrum by reporting a low-temperature phase, where all three symmetrically independent molecules are present in a bent formation. This reversible enantiotropic phase transition occurs in the temperature range between 80 K and 130 K and provides a rationale for the unexpected linear molecule based in entropy beyond hand-waving explanations such as electronic reasons or packing effects.

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 ().

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.