Sodium reduction of [{SiN Dipp }Mg] [{SiN Dipp } = {CH 2 SiMe 2 N(Dipp)} 2 ; Dipp = 2,6-i-Pr 2 C 6 H 3 ] provides the Mg(I) species, [{SiN Dipp }MgNa] 2 , in which the long Mg−Mg bond (>3.2 Å) is augmented by persistent Na−aryl interactions. Computational assessment indicates that this molecule is best considered to comprise a contiguous tetrametallic core, a viewpoint borne out by its reaction with CO, which results in ethynediolate formation mediated by the dissimilar metal centers.

Copper‐alumanyl complexes, [LCu‐Al(SiNDipp)], where L=carbene=NHCiPr (N,N′‐diisopropyl‐4,5‐dimethyl‐2‐ylidene) and Me2CAAC (1‐(2,6‐diisopropylphenyl)‐3,3,5,5‐tetramethyl‐pyrrolidin‐2‐ylidene) and featuring unsupported Al−Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides and CO2 implies an ambiphilicity in the Cu–Al interaction that is dependent on the identity of the carbene co‐ligand.

The seven-membered cyclic potassium alumanyl species, [{SiN Mes }AlK] 2 [{SiN Mes } = {CH 2 SiMe 2 N(Mes)} 2 ; Mes = 2,4,6-Me 3 C 6 H 2 ], which adopts a dimeric structure supported by flanking K-aryl interactions, has been isolated either by direct reduction of the iodide precursor, [{SiN Mes }AlI], or in a stepwise manner via the intermediate dialumane, [{SiN Mes }Al] 2 . Although the intermediate dialumane has not been observed by reduction of a Dipp-substituted analogue (Dipp = 2,6-i-Pr 2 C 6 H 3 ), partial oxidation of the potassium alumanyl species, [{SiN Dipp }AlK] 2 , where {SiN Dipp } = {CH 2 SiMe 2 N(Dipp)} 2 , provided the extremely encumbered dialumane [{SiN Dipp }Al] 2 . [{SiN Dipp } AlK] 2 reacts with toluene by reductive activation of a methyl C(sp 3 )-H bond to provide the benzyl hydridoaluminate, [{SiN Dipp }AlH(CH 2 Ph)]K, and as a nucleophile with BPh 3 and RN=C=NR (R = i-Pr, Cy) to yield the respective Al-B-and Al-Cbonded potassium aluminaborate and alumina-amidinate products. The dimeric structure of [{SiN Dipp }AlK] 2 can be disrupted by partial or complete sequestration of potassium. Equimolar reactions with 18-crown-6 result in the corresponding monomeric potassium alumanyl, [{SiN Dipp }AlÀ K(18-cr-6)], which provides a rare example of a direct AlÀ K contact. In contrast, complete encapsulation of the potassium cation of [{SiN Dipp }AlK] 2 , either by an excess of 18-cr-6 or 2,2,2-cryptand, allows the respective isolation of bright orange chargeseparated species comprising the 'free' [{SiN Dipp }Al] À alumanyl anion. Density functional theory (DFT) calculations performed on this moiety indicate HOMO-LUMO energy gaps in the of order 200-250 kJ mol À 1 .

.Reactions of the seven-membered heterocyclic potassium diamidoalumanyl, [K{Al(SiNDipp)}]2 (SiNDipp = {CH2SiMe2NDipp}2; Dipp = 2,6-di-isopropylphenyl), with a variety of Cu(I), Ag(I) and Au(I) chloride N-heterocyclic carbene (NHC) adducts are described. The...

Ionic compounds containing sodium cations are notable for their stability and resistance to redox reactivity unless highly reducing electrical potentials are applied. Here we report that treatment of a low oxidation state {Mg2Na2} species with non-reducible organic bases induces the spontaneous and completely selective extrusion of sodium metal and oxidation of the Mg(I) centers to the more conventional Mg(II) state. Although these processes are also characterized by a structural reorganisation of the initially chelated diamide spectator ligand, computational quantum chemical studies indicate that intramolecular electron transfer is abetted by the frontier molecular orbitals (HOMO/LUMO) of the {Mg2Na2} ensemble, which arise exclusively from the 3s valence atomic orbitals of the constituent sodium and magnesium atoms.