Neutral, mononuclear aluminum and gallium radicals, stabilized by cyclic (alkyl)­(amino)­carbene (cAAC), were synthesized. LMCl2 upon reduction with KC8 in the presence of cAAC afforded the radicals LMCl­(cAAC), where L = PhC­(N t Bu)2 and M = Al (1), Ga (2). The radicals were characterized by X-ray crystallography, electron paramagnetic resonance (EPR) spectroscopy, and mass spectrometry. EPR, SQUID measurement, and computational calculations confirmed paramagnetism of the radicals with unpaired spin mainly on cAAC.

Within this work, the field of bulky methanides in metal coordination is exceeded by the synthesis of the versatile and promising bis(4,6-isopropylbenzoxazol-2-yl)methane (7) ligand platform. As an enhancement in this class of ligands, isopropyl (iPr) substituents as steric-demanding groups have been successfully introduced in proximity to the coordination pocket, mimicking the shielding abilities of the ubiquitous NacNac ligand scaffold to improve the steric protection of a coordinated s-block metal cation. A percent buried volume (% V) calculation as well as an electronic structure analysis shades light onto the shielding and electronic abilities of the ligand in comparison to other selected methanides and diketiminates. Upon deprotonation with a variety of different group 1 and 2 metalation agents, a row of novel s-block metal complexes of the parent deprotonated monoanionic ligand 7 was obtained and structurally, as well as spectroscopically, characterized. In particular, in this context, the alkali-metal precursor complexes [Li(THF){(4,6-iPr-NCOCH)CH}] (8) and [K{μ-(4,6-iPr-NCOCH)CH}] (9) as well as the alkaline-earth-metal compounds [MgCl(THF){(4,6-iPr-NCOCH)CH}] (10) and [M(THF){(4,6-iPr-NCOCH)CH}] [M = Mg, n = 0 (11); M = Ca, n = 1 (12); M = Sr, n = 1 (13); M = Ba, n = 1 (14)] were successfully synthesized. Especially, the latter four exhibit interesting trends in the solid state as well as in solution within the metal series.

Carbenes are known as donor molecules to form with chloroalane adducts, which enhances their aerobic and thermal stabilities. In contrast, the insertion products (cAACH)­AlCl2(cAAC) (1) and (cAACH)­AlHCl­(THF) (2; THF = tetrahydrofuran) have been formed in the reaction of a cyclic alkyl­(amino)­carbene (cAAC:) with HAlCl2, and H2AlCl, respectively. PhC­(NtBu)2Li as the precursor for the reaction with HAlCl2 in a molar ratio of 2:1 can easily form compound [PhC­(NtBu)2]2AlH (3) with five-coordinate aluminum. The new products have been studied by spectroscopic methods and single-crystal X-ray diffraction.

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-SbCl2) with KC8 in the presence of silylene chloride afforded L(Cl)­SiSbTip (1) and L­(Cl)­SiSbTerPh (2), respectively. Compounds 1 and 2 further undergo reduction with KC8 to produce TipSbLSiLSiSbTip (3) and TerPhSbLSiLSiSbTerPh (4). The solid-state structures and DFT studies show that all compounds have σ-type lone pairs at each Sb atom. It forms a strong pseudo-π-bond with Si. The pseudo-π-bond is formed by the hyperconjugative donation of the π-type lone pair at Sb to the Si-N σ* MO. The quantum mechanical studies indicate that compounds 3 and 4 has delocalized pseudo-π-MOs arising from hyperconjugative interactions. Hence, 1 and 2 can be considered as isoelectronic to imine, while 3 and 4 are isoelectronic to ethane-1,2-diimine. The proton affinity studies indicate that the pseudo-π-bond resulting from the hyperconjugative interaction is more reactive than the σ-type lone pair.

Herein, we report the stabilization of lithium‐ion as the source of lithium to use as a trans‐metalation reagent [{PhC(NtBu)2Si(tBu)Li}2I(tBuN)2CPh] (1). The reaction of 3 equivalents of the LSitBu (L=PhC(NtBu)2) 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. Whereas the reaction of the LSiCl with 1.5 equivalents of carbodiimide (CyN)2C at room temperature affords compound [PhC(NtBu)2Si(Cl)(NCy)2NCy] (2) with the CN2SiN2C skeleton containing silicon as a central atom. Both the compounds were fully characterized by NMR, mass spectrometry, X‐ray crystallographic analysis, and quantum mechanical calculations.