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The installation of electron-withdrawing functional groups at the carbocyclic backbone of aminotroponiminate (ATI) ligands is a versatile method for influencing the electronic properties of the resulting ATI complexes. We report here Li, Na, and K salts of an ATI ligand with a phenylsulfinyl substituent in the backbone. It is demonstrated that the sulfinyl group actively contributes to the coordination chemistry of these complexes, effectively competing with neutral donor ligands such as thf or pyridine in the solid state (XRD), in solution (DOSY NMR spectroscopy), and in the gas phase (DFT). The impact of the phenylsulfinyl group on the redox properties of the complexes have been investigated and access to sodium sodiate species through ligand-induced disproportionation has been studied. Transfer of the ATI ligand to the heavy p-block element bismuth has been demonstrated. Analytical techniques applied in this work include multinuclear and DOSY NMR spectroscopy, cyclic voltammetry, DFT calculations, and single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Large silver(I) clusters stabilized by the dianionic carba‐closo‐dodecaboranylethynyl ligand were obtained. Crystallization of polymeric {Ag2(12‐C≡C‐closo‐1‐CB11H11)}n from dimethyl sulfoxide afforded [Ag14(12‐C≡C‐closo‐1‐CB11H11)7(DMSO)12]·DMSO that contained an AgI10 cage augmented by four AgI ions. Crystals of [Ag16(12‐C≡C‐closo‐1‐CB11H11)8(THF)12]·2THF were obtained from anhydrous THF and {Ag2(12‐C≡C‐closo‐1‐CB11H11)}n. In the presence of moisture the similar but water‐containing complex [Ag16(12‐C≡C‐closo‐1‐CB11H11)8(THF)12(H2O)2]·2.5THF was identified. Both silver(I) clusters are composed of a central octahedral AgI6 unit and ten further silver(I) ions bonded via argentophilic interactions. [Ag14(12‐C≡C‐closo‐1‐CB11H11)7(DMSO)12]·DMSO and [Ag16(12‐C≡C‐closo‐1‐CB11H11)8(THF)12]·2THF were characterized by elemental analysis and vibrational (IR and Raman) as well as NMR spectroscopy. In addition, the crystal structures of [Ag25(12‐C≡C‐closo‐1‐CB11H11)12(CH3CN)13.5(OH)]·0.5CH3CN and [Ag25(12‐C≡C‐closo‐1‐CB11H11)12{(CH3)2CO}13.5(H2O)Cl]·15(CH3)2CO were determined. Both compounds contain AgI14 rhombic dodecahedrons augmented by eleven silver(I) ions. A hydroxide or a chloride template ion is present in the center of the rhombic dodecahedron, respectively. [ABSTRACT FROM AUTHOR]

The steric and electronic properties of aryl substituents in monoaryl borohydrides (Li[ArBH3]) and dihydroboranes were systematically varied and their reactions with [Ru(PCy3)2HCl(H2)] (Cy: cyclohexyl) were studied, resulting in bis(σ)‐borane or terminal borylene complexes of ruthenium. These variations allowed for the investigation of the factors involved in the activation of dihydroboranes in the synthesis of terminal borylene complexes. The complexes were studied by multinuclear NMR spectroscopy, mass spectrometry, X‐ray diffraction analysis, and density functional theory (DFT) calculations. The experimental and computational results suggest that the ortho‐substitution of the aryl groups is necessary for the formation of terminal borylene complexes. [ABSTRACT FROM AUTHOR]

A series of 22 new bis(phosphine), bis(carbene), and bis(isonitrile) tetrahalodiborane adducts has been synthesized, either by direct adduct formation with highly sensitive B2X4 precursors (X=Cl, Br, I) or by ligand exchange at stable B2X4(SMe2)2 precursors (X=Cl, Br) with labile dimethylsulfide ligands. The isolated compounds have been fully characterized using NMR spectroscopy, elemental analysis, and, for 20 of these compounds, single‐crystal X‐ray diffraction, revealing an unexpected variation in the bonding motifs. In addition to the classical B2X4L2 diborane(4) bis‐adducts, certain more sterically demanding carbene ligands induce a halide displacement which led to the first halide‐bridged monocationic diboron species, [B2X3L2]A (A=BCl4, Br, I). Furthermore, low‐temperature 1:1 reactions of B2Cl4 with sterically demanding N‐heterocyclic carbenes led to the formation of kinetically unstable mono‐adducts, one of which was structurally characterized. A comparison of the NMR spectra and structural data of new and literature‐known bis‐adducts shows several trends pertaining to the nature of the halides and the stereoelectronic properties of the Lewis bases employed. [ABSTRACT FROM AUTHOR]

Herein, two new quadrupolar acceptor‐π‐donor‐π‐acceptor (A‐π‐D‐π‐A) chromophores have been prepared featuring a strongly electron‐donating diborene core and strongly electron‐accepting dimesitylboryl (BMes2) and bis(2,4,6‐tris(trifluoromethyl)phenyl)boryl (BFMes2) end groups. Analysis of the compounds by NMR spectroscopy, X‐ray crystallography, cyclic voltammetry, and UV/Vis‐NIR absorption and emission spectroscopy indicated that the compounds have extended conjugated π‐systems spanning their B4C8 cores. The combination of exceptionally potent π‐donor (diborene) and π‐acceptor (diarylboryl) groups, both based on trigonal boron, leads to very small HOMO–LUMO gaps, resulting in strong absorption in the near‐IR region with maxima in THF at 840 and 1092 nm and very high extinction coefficients of ca. 120 000 m−1 cm−1. Both molecules also display weak near‐IR fluorescence with small Stokes shifts. [ABSTRACT FROM AUTHOR]

A new isomer of borepin, identified as 2‐borabicyclo[3.2.0]hepta‐3,6‐diene by single‐crystal X‐ray diffraction and heteronuclear NMR spectroscopy, was obtained by reaction of 1‐mesityl‐2,3,4,5‐tetraphenylborole with the diaminoalkyne bis(piperidyl)acetylene. Analogous reactions of the alkyne with other borole derivatives generated seven‐membered borepins, in which a second equivalent of the alkyne was found to insert into the exocyclic B−C bond. Results of mechanistic DFT studies as well as differences in the reactivity of the boroles toward the diaminoalkyne are discussed. Short Fused: A new isomer of borepin, 2‐borabicyclo[3.2.0]heptadiene, was synthesized by the reaction of a perarylated borole with one equivalent of bis(piperidyl)acetylene (see scheme). Analogous reactions of the alkyne with 1‐phenyl‐ and 1‐thienyl‐2,3,4,5‐tetraphenylborole yielded seven‐membered borepin derivatives, in which the exocyclic B−aryl bond underwent a 1,2‐carboboration with a second equivalent of the alkyne. [ABSTRACT FROM AUTHOR]

The reactivity of the diaminoacetylene Pip-C≡C-Pip (Pip=piperidyl=NC5H10) towards phenyldichloro- and triphenylborane is presented. In the case of the less Lewis acidic PhBCl2, the first example of a double Lewis adduct of a vicinal dicarbenoid is reported. For the more Lewis acidic triphenylborane, coordination to the bifunctional carbene leads to a mild B-C bond activation, resulting in a syn-1,2-carboboration. Ensuing cis/trans isomerization yields a novel ethylene-bridged frustrated Lewis pair (FLP). The compounds were characterized using multinuclear NMR spectroscopy, structural analysis, and mass spectrometry. Reactivity studies of both isomers with the N-heterocyclic carbene 1,3-dimethylimidazol-2-ylidene (IMe) aided in elucidating the proposed isomerization pathway. DFT calculations were carried out to elucidate the reaction mechanism. The rather low free energy of activation is consistent with the observation that the reaction proceeds smoothly at room temperature. [ABSTRACT FROM AUTHOR]