The cyclic alkyl(amino) carbene-anchored silylene-phosphinidene was isolated as L-Si-P(:cAAC-Me) (L=benzamidinate) at room temperature, synthesized from the reduction of L-Si(Cl )-P(:cAAC-Me) (1) using two equivalents of KC . Compound 1 was prepared by the oxidative addition of a chlorophosphinidene to the benzamidinate substituted silylene center. This is the first molecular example of a silylene-phosphinidene characterized by single-crystal X-ray structural analysis. Moreover, H, P, and also Si NMR spectroscopic data supported the formulation of the products. The theoretical calculations of compound 2 are in good agreement with the experimental results.

A new NMR method for the structure elucidation of lithium compounds under solution-like conditions is presented. It is based on the measurement of 7 Li residual quadrupolar couplings (RQCs) in a stretched polystyrene (PS) gel, and comparison to RQCs predicted from crystal or DFTderived model structures in combination with alignment tensors derived from one-bond 1 H, 13 C residual dipolar couplings (RDCs). The method was applied to five lithium model complexes containing monoanionic, bidentate bis(benzoxazole-2-yl)methanide, bis(benzothiazole-2yl)methanide and bis(pyridyl)methanide ligands, of which two are first introduced in this work. In agreement with the crystalline state, four complexes are monomeric with Li coordinated fourfold by two additional THF molecules, whereas in one complex bulky tBu groups only provide space for one additional THF molecule.

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, an aluminum dihydride complex ([(4‑MeBox2CH)­AlH2]) (1) based on the bis­(4-methyl-benzoxazol-2-yl)­methanide ligand was synthesized and characterized by spectroscopic methods (NMR, ATR-IR, and fluorescence), DSC (differential scanning calorimetry), mass spectrometry (LIFDI), and single crystal X-ray diffraction. The reactivity of alane 1 was investigated toward the reducing agents [DippNacNacAlI] and [(MesNacNacMgI)2], which gave the dialane compounds [(4‑MeBox2CH)­HAlII–AlIIH­(DippNacNac)] (2) and [{(4‑MeBox2CH)­AlIIH}2] (4a), respectively. Furthermore, dialuminoxanes [{(4‑MeBox2CH)­AlH}2(μ-O)] (4b) and [({(MesNacNac)­Mg}2(μ-H))­{H3AlII–AlIIH­(4‑MeBox2CH)}] (4c) were isolated as byproducts, with 4b co-crystallizing with 4a. The hydricity of both hydrides in the mixed-ligated dialane 2 were examined by a reaction with 1 equiv of trityl borate ([Ph3C]­[B­(C6F5)4]), which resulted in [(4‑MeBox2CH)­HAlII–AlII(DippNacNac)]­[B­(C6F5)4] (3). Due to the formation of 4b, complex 1 was reacted with 0.5 equiv of water, which causes the likely synthesis of insoluble oligomeric alumoxanes. To prevent this reaction and support the formation of well-defined dialumoxanes, 1 was initially converted to [(4‑MeBox2CH)­(DippO)­AlH] (5) by the deprotonation of 2,6-diisopropylphenol (propofol). This sterically encumbered compound 5 was subsequently reacted with 0.5 equiv of water, which resulted in defined molecules of [{(4‑MeBox2CH)­(DippO)­Al}2(μ-O)] (6). All these compounds exemplify the versatility of the 4‑MeBox2CH ligand in low-valent aluminum chemistry.

On the basis of the bulky bis(4-benzhydryl-benzoxazyl-2-yl)methane ligand ( 4 -B z h H 2 Box 2 CH 2 ), neutral monovalent group 13 complexes [M 13 ( 4-BzhH2 Box 2 CH)] [M 13 = Tl (1), In (2), or Ga (3)] have been synthesized by salt metathesis reaction of the corresponding potassium or sodium precursor and TlOTf, InOTf, or "GaI". The diiodido gallium species [GaI 2 ( 4-BzhH2 Box 2 CH)] (3a) was realized as a byproduct once the synthesis of 3 was carried out at higher temperatures. The synthesis of [AlI 2 ( 4-BzhH2 Box 2 CH)] ( 6) as a potential precursor for an aluminum(I) congener was accomplished by two alternative synthetic routes. During one of those procedures, [AlMe 2 ( 4-BzhH2 Box 2 CH)] (4) was synthesized in good yields by deprotonation with an AlMe 3 solution (method A). Subsequently, 4 was converted to the monoiodinated species [AlMeI( 4-BzhH2 Box 2 CH 2 )] ( 5) using 1 equiv of I 2 or to 6 by iodination with 2 equiv of I 2 at 70 °C for 4 days. As an alternative, complex 6 could be prepared by iodination of 1 equiv of I 2 and [AlH 2 ( 4-BzhH2 Box 2 CH)] ( 7), which was previously obtained by facile reaction of 4-BzhH2 Box 2 CH 2 and AlH 3 NMe 2 Et. All main products 1−7 were completely characterized by nuclear magnetic resonance spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray structure determination. Alane 7 was additionally analyzed by solid-state fluorescence spectroscopy. Density functional theory calculations on [M 13 ( 4-BzhH2 Box 2 CH)] [M 13 = Tl (1), In (2), Ga (3), or Al] revealed that the complexes consist of monovalent group 13 cations coordinated by an anionic ( 4-BzhH2 Box 2 CH) ligand similar to metallacycles incorporating a NacNac ligand.