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Amino imidazoline‐2‐imines (AmIm) are a new class of chelating, monoanionic N,N'‐donor ligands stronger than the analogous β‐diketiminate ligands and give rise to five‐membered metallacycles. The coordination chemistry of the monoanionic ligands 1,2‐NHC=N−C6H4−NDipp− (i), cis‐1,2‐NHC=N−CMe=CMe−NDipp− (ii) was towards magnesium was investigated with the focus on the stabilization of low‐valent magnesium(I) species, NHC=cyclo‐C(NiPr2CMe)2, Dipp=2,6‐iPrC6H3. Both ligand systems (i) and (ii) form heteroleptic magnesium iodide species with were subjected to reduction. The complex [Mg(1,2‐NHC=N−C6H4−NDipp)]2 was found to be insoluble, which prevented further purification. In contrast, the yield of the analogous complex [Mg(cis‐1,2‐NHC=N−CMe=CMe−NDipp)]2 was very low. As a significant side product the homoleptic complex [Mg(cis‐1,2‐NHC=N−CMe=CMe−NDipp)2] was identified. [ABSTRACT FROM AUTHOR]

Donor‐acceptor cyclopropanes or cyclobutanes are dipolar reagents, which are widely used in the synthesis of complex organic (hetero)cycles in ring expansion reactions. Applying this concept to boron containing heterocycles, the four‐membered borete cyclo‐iPr2N‐BC10H6 reacted with the carbon donor ligands 2,6‐xylylisonitrile and the carbene IMes :C(NMesCH)2 with ring expansion and ring fusion, respectively. In particular, the tetracyclic structure formed with IMes displays zwitterionic character and absorption in the visible region. In contrast to the carbene IMes, the heavier carbenoids :Si(NDippCH)2 and :Ga(AmIm) with a two‐coordinate donor atom afford spiro‐type bicyclic compounds, which display four‐coordinate geometry at silicon or gallium. (TD‐)DFT calculations provide deeper insight into the mechanism of formation and the absorption properties of these new compounds. [ABSTRACT FROM AUTHOR]

Boron reluctantly forms B=X (X=O, S, Se, Te) moieties, which has stimulated the quest for such species in the past few years. Based on the N,N′‐chelating β‐diketiminato ligand (HNacNac), a new amido imidazoline‐2‐imine ligand system (HAmIm) is presented, giving rise to the isolation of an exhaustive series of Lewis acid free, monomeric chalcogen B=X boranes with documented π‐bond character between boron and the chalcogen. The chalcogenoboranes are isoelectronic and isolobal to the respective ketones. The chemical behavior of the oxoborane (B=O) strongly resembles the classical carbonyl reactivity in C=O bonds. The improved stability provided by HAmIm arises from the formation of more‐stable five‐membered boron chelates versus the six‐membered NacNac analogues and from the imidazoline‐2‐imine moiety providing enhanced σ‐ and π‐donation. The HAmIm ligand class may supersede the widely employed NacNac system in certain applications. [ABSTRACT FROM AUTHOR]

The synthesis of chiral ortho-carbaboranyl bis(aminohalophosphines) is presented, and spectroscopic and crystallographic data of these compounds are discussed. Furthermore, their reactivity toward alcoholysis was investigated. Quantum chemical calculations showed that the inhibition of methanolysis is of kinetic and not of thermodynamic origin. The disubstitution of the carbaboranes leads to PïP interactions as strong as a hydrogen bond that extremely lower the rate of the methanolysis. [ABSTRACT FROM AUTHOR]

Correction for '"Give me five" – an amino imidazoline-2-imine ligand stabilises the first neutral five-membered cyclic triel(I) carbenoides' by Lars Denker et al., Chem. Commun., 2021, 57, 2816–2819, DOI: 10.1039/D1CC00010A. [ABSTRACT FROM AUTHOR]