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.

A series of new alkali metal complexes containing deprotonated bisheterocyclomethanide were synthesised and structurally as well as spectroscopically characterised. Starting from the neutral bis-(benzoxazol-2-yl)methane ({NCOC 6 H 4 } 2 CH 2 ), the complexes were obtained by facile deprotonation of the methylene bridge with nbutyllithium (nBuLi) or potassium hydride. Each of the resulting complexes(n → ∞) was analysed in the solid state by single crystal X-ray diffraction and in solution by various NMR techniques. All the compounds show a nearly planar ligand with the alkali metal ion chelated by the two ring nitrogen atoms of the conjugated C 3 N 2 moiety. Furthermore, water NMR titration experiments revealed that both compounds 2 and 3 are examples of water-stable reactive organo potassium compounds. Due to their hydrolysis stability, these complexes are under further investigations in deep eutectic solvents.

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.