The reactions of anionic aluminium or gallium nucleophiles {K­[E­(NON)]}2 (E = Al, 1; Ga, 2; NON = 4,5-bis­(2,6-diisopropylanilido)-2,7-ditert-butyl-9,9-dimethylxanthene) with beryllocene (BeCp2) led to the displacement of one cyclopentadienyl ligand at beryllium and the formation of compounds containing Be–Al or Be–Ga bonds (NON)­EBeCp (E = Al, 3; Ga, 4). The Be–Al bond in the beryllium–aluminyl complex [2.310(4) Å] is much shorter than that found in the small number of previous examples [2.368(2) to 2.432(6) Å], and quantum chemical calculations suggest the existence of a non-nuclear attractor (NNA) for the Be–Al interaction. This represents the first example of a NNA for a heteroatomic interaction in an isolated molecular complex. As a result of this unusual electronic structure and the similarity in the Pauling electronegativities of beryllium and aluminium, the charge at the beryllium center (+1.39) in 3 is calculated to be less positive than that of the aluminium center (+1.88). This calculated charge distribution suggests the possibility for nucleophilic behavior at beryllium and correlates with the observed reactivity of the beryllium–aluminyl complex with N,N′-diisopropylcarbodiimidethe electrophilic carbon center of the carbodiimide undergoes nucleophilic attack by beryllium, thereby yielding a beryllium–diaminocarbene complex.

The synthesis of beryllium halide etherates and the solution behavior in benzene, dichloromethane, and chloroform was studied by NMR, IR, and Raman spectroscopy. Mononuclear units of [BeX 2(L)2] (X = Cl, Br, I; L = Et2O, thf) were identified as the favorably formed species in solution. Treatment of the mononuclear diethyl ether beryllium halide adduct with one equivalent beryllium halide formed the dinuclear compounds [BeX 2(OEt2)]2 (X = Cl, Br, I). The solid-state structures of [BeCl2(thf)2] and [BeBr2(thf)2] have been determined by single crystal X-ray diffraction analysis. [BeI2(thf)2] decomposed in all solvents. In CD2Cl2 the salt [Be(thf)4]I2 was formed, whereas in C6D6 and CDCl3, BeI2 precipitated and [BeI(thf)3]+, [Be(thf)4]2+ together with the thf ring-opening product [Be(μ 2-O(CH2)4I)I(thf)]2 were observed in solution.

The reactions of beryllium halides with diphenyl beryllium were investigated in the N‐ and O‐donor solvents NEt3 and THF, as well as in benzene and dichloromethane in the presence of the Lewis basic ligands THF, NEt3 and N‐heterocyclic carbenes with various steric demand. In all cases the selective formation of heteroleptic beryllium Grignard compounds of the general formula [(L)1‐2BePhX]1‐2 (X = Cl, Br, I; L = C‐, N‐, O‐donor ligand) was observed. The stability of these complexes was investigated computationally, while the differences between homo‐ and heteroleptic systems were also evaluated NMR spectroscopically and with single crystal X‐ray diffraction. Mechanistic studies on the formation and speciation of these beryllium Grignard complexes in solution were performed.

Complexes [Fe(X-salEen)2]BPh4·DMF, with X = Br (1), Cl (2), and F (3), were crystallised from N-ethylethylenediamine with the aim of understanding the role of a high boiling point N,N′-dimethylformamide solvate in the spin crossover phenomenon. The counter ion was chosen for only being able to participate in weak intermolecular interactions. The compounds were structurally characterised by single crystal X-ray diffraction. Complex 1 crystallised in the orthorhombic space group P212121, and complexes 2 and 3 in the monoclinic space group P21/n. Even at room temperature, low spin was the predominant form, although complex 2 exhibited the largest proportion of the high-spin species according to both the magnetisation measurements and the Mössbauer spectra. Density Functional Theory calculations were performed both on the periodic solids and on molecular models for complexes 1–3 and the iodide analogue 4. While all approaches reproduced the experimental structures very well, the energy balance between the high-spin and low-spin forms was harder to reproduce, though some calculations pointed to the easier spin crossover of complex 2, as observed. Periodic calculations with the functional PBE led to very similar ΔEHS-LS values for all complexes but showed a preference for the low-spin form. However, the single-point calculations with B3LYP* showed, for the model without solvate, that the Cl complex should undergo spin crossover more easily. The molecular calculations also reflected this fact, which was more clearly defined when the cation–anion–solvate model was used. In the other models there was not much difference between the Cl, Br, and I complexes.

Anionic lithium-containing species were predicted to impact ionic liquid-based electrochemical applications but have hitherto never been isolated from ionic liquid systems. Here, we report the first representatives of this class of compounds, inochloridolithates, comprising [LiCl 2 ] − and [Li 2 Cl 3 ] − polyanions from ionothermal reactions. Such compounds are obtained at moderate temperatures with imidazolium-based ionic liquids and LiCl. The addition of an auxiliary ammonium salt enhances the lattice energy to yield an ammonium lithate in good yields, which enables extensive investigations including solid-state nuclear magnetic resonance, infrared, and Raman spectroscopy. The structural motifs of inolithates are related to ino-silicates, as 1D-extended anionic substructures are formed. Despite this analogy, according to density functional theory calculations with periodic boundary conditions, no evidence of covalent bonding in the anionic moieties is found−indicating packing effects to be the main cause for the formation. Based on an in-depth analysis of the different synthetic parameters, this class of compounds is discussed as an intermediate in ionic liquid applications and could serve as a model system for electrochemical lithium-based systems.