We report the design, synthesis, structure, bonding, and reaction of a neutral 2p aromatic three-membered disilaborirane. The disilaborirane is synthesized by a facile one-pot reductive dehalogenation of amidinato-silylene chloride and dibromoarylborane with potassium graphite. Despite the tetravalent arrangement of atoms around silicon, the threemembered silicon-boron-silicon ring is aromatic, as evidenced by NMR spectroscopy, nucleus independent chemical shift calculations, first-principles electronic structure studies using density functional theory (DFT) and natural bond orbital (NBO) based bonding analysis. Trimethylsilylnitrene, generated in situ, inserts in the SiÀSi bond of disilaborirane to obtain a four-membered heterocycle 1-aza-2,3-disila-4-boretidine derivative. Both the heterocycles are fully characterized by X-ray crystallography. The synthesis of three-membered aromatic rings has been a fascinating topic for the chemical community during the last decades. Aromaticity and Hückel 4n + 2 rule continue its diversity with the smallest, largest, homo-, hetero-, Mçbius, all-carbon, organometallic-and so on, but most of these involve overlap of p, d and f orbitals. [1-3] A challenging question is it possible to generate a carbon-free neutral threemembered aromatic ring. The neutral three-membered aromatic compound with 2p electrons is one of the longest quests to inorganic, organic and theoretical chemists. [1, 4] Most of the reported small aromatic species are anionic or cationic. [4-11] Recent reports of the carbon-free aromatic systems all involve charged species: B 3 À (observed in gas phase), [6] Li 3 + (observed in gas phase), [7] [B 3 (CO) 3 ] + (observed in gas phase), [8] [B 3 (NCy 2) 3 ] 2À (characterized by X-ray), [9] [SiRSi 2 R' 2 (R = Si t Bu 3 , R' = SiMe t Bu 2)] + (characterized by X-ray), [10] [Ge 3 R 3 , R = Si t Bu 3 ] + (characterized by X-ray). [11] To develop carbon-free small neutral Hückel p systems with orbitals beyond p, d and f, unique design strategies must be assembled. Here, we present a novel approach where two of the three p orbitals are replaced by s* MOs to generate a neutral 2p aromatic three-membered disilaborirane. To synthesize carbon-free neutral three-membered 2p aromatic system, we replace one of the CH group of the classical cyclopropenyl cation by isoelectronic BR group and the remaining two CH groups by two amidinato-silylene groups to retain the 2p aromaticity, leading to the formation of a disilaborirane. [12] We envision that the extra electrons from the two amidinato-ligands will populate the stable delocalized p MO resulting from the 2p orbital of boron atom and the two s* MOs on silicon atoms in the neutral Si 2 B three-membered ring. 13 The two p electrons will conjugate in the field of the three nuclei of Si-B-Si. Accordingly, we design and synthesize the three-membered disilaborirane (Scheme 1). A 2:1:4 molar ratio of amidinato-silylene chloride [LSi-Cl; L = PhC(NtBu) 2 ], dibromo(2,4,6-triisopropylphenyl)borane and KC 8 is reacted in THF at À78 8C and...

The reduction of TipMCl (Tip=2,4,6-triisopropylphenyl) (M=Si, Ge) with KC in the presence of cyclic alkyl(amino) carbene (cAAC) afforded the acyclic silanylidene and germanylidene anions in the form of potassium salt [K(cAAC)MTip] (M=Si (1); Ge (2)). The silanylidene and germanylidene anions are valence-isoelectronic to the well-studied phosphinidene and are a new class of acyclic anions of Group 14. Compounds 1 and 2 were isolated and well characterized by NMR and single-crystal X-ray structure analysis. Furthermore, the structure and bonding of compounds 1 and 2 was investigated by computational methods.

C-H/C-C functionalizations with methylenecyclopropanes (MCPs) were accomplished with a versatile base-metal catalyst. A robust manganese(I) complex enabled the expedient annulation of MCPs by synthetically meaningful ketimines to deliver, upon one-pot hydroarylation, densely substituted polycylic anilines in a step-economical fashion. Mechanistic studies provided strong support for a facile organometallic C-H manganation, while typical cobalt, ruthenium, rhodium, and palladium catalysts were found completely ineffective.

This work describes the synthesis and coordination behavior of a new mixed‐donor ligand PhC(NtBu)2SiC6H4PPh2 (1) containing both silylene and phosphine donor sites. Ligand 1 was synthesized from a reaction of ortho‐lithiated diphenylphosphinobenzene (LiC6H4PPh2) with chlorosilylene (PhC(NtBu)2SiCl). Treatment of 1 with Se and GeCl2 resulted in SiIV compounds 2 and 3 by selective oxidation of the silylene donor. This strong σ‐donor ligand induces dissociation of CuCl and PhBCl2 leading to formation of ionic complexes 4 and 5 respectively. The reaction of 1 with ZnCl2 and AlCl3 resulted in the formation of chelate complexes 5 and 7, respectively, while treatment with EtAlCl2 and GaCl3 forms monodentate complexes 8 and 9. X‐ray analysis of 4 showed that the copper is in the spiro center of the two five‐membered rings. Moreover, the copper(I)chloride has not been oxidized but dissociates to Cu+ and [CuCl2]−. All the compounds are well characterized by mass spectrometry, elemental analysis, NMR spectroscopy, and single‐crystal X‐ray diffraction studies.

In this Article, the organolithiums [((−)-sparteine)-Li t Bu] (1), [(ABCO)Li t Bu] 2 (2), and [(ABCO) 2 (Li i Pr) 4 ] (3) are investigated by means of experimental and theoretical charge density determination to elucidate the nature of the Li−C and Li− N bonds. Furthermore, the valence shell charge concentrations (VSCCs) in the nonbonding region of the deprotonated C α -atom will provide some insight on the localization of the carbanionic lone pair. Analysis of the electron density (ρ(r BCP )), Laplacian (∇ 2 ρ(r BCP )), and the energy decomposition (EDA) confirmed that the Li−C/N bond exhibits astonishingly similar characteristics, to reveal an increasingly polar contact with decreasing aggregate size. This explains former observations on the incorporation of halide salts in organolithium reagents. Furthermore, it could be shown that the bonding properties of the i Pr group are similar to those of the t Bu substituent. The accuracy of fit to all previously determined properties in organolithiums is remarkable.