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 behavior of a variety of Lewis bases toward diphenylberyllium has been investigated, demonstrating the high Lewis acidity and electron deficiency of diphenylberyllium. A range of monodentate donors with vastly different steric and electronic properties were used, namely, pyridine, NEt 3 , THF, THT, and PMe 3 . The Be-donor bond strength was investigated through application of vacuum, and transformations between the mono-and disubstituted beryllium centers were investigated through stoichiometric addition of additional BePh 2 . Strong electron donors (Nheterocyclic carbenes) with vastly different steric profiles were then investigated, highlighting that steric interactions are more dominant than electronics. Adducts of bidentate ligands with O-, N-, and Pdonating sites were also produced.

It is common knowledge that metal-to-ligand π back-donation requires filled atomic orbitals at the metal center. However, we show through a combined experimental and theoretical approach that Be­(II)→N-heterocyclic carbene (NHC) π back-donation is present in the two carbene adducts [(iPr)­BeBr2] (1) and [(iPr)2BeBr2] (2) (iPr = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene). These complexes were characterized with NMR, IR, and Raman spectroscopy as well as with single-crystal X-ray diffractometry. The unusual bonding situation is understood from the results of energy decomposition analysis in combination with natural orbital for chemical valence and quantum theory of atoms-in-molecules analysis. The obtained findings shed light on the unusually high Be–C bond strength in carbene adducts to beryllium compounds and rationalize their geometry and reactivity.

The thioether diadducts [(SMe2)2BeCl2], [(SMe2)2BeBr2] and [(SMe2)2BeI2] have been prepared and converted to the corresponding μ2‐halido bridged monoadducts [(SMe2)BeCl2]2, [(SMe2)BeBr2]2 and [(SMe2)BeI2]2. These complexes have been characterized with IR and NMR spectroscopy as well as X‐ray crystallography. Furthermore, their long term stability in chlorinated solvents was tested, which yielded beryllate salts containing the [SMe3]+ cation.

Treatment of the new methanediide-methanide complex [Dy(SCS)(SCSH)(THF)] (1Dy, SCS = {C(PPh2S)2}2-) with alkali metal alkyls and auxillary ethers produces the bis-methanediide complexes [Dy(SCS)2][Dy(SCS)2(K(DME)2)2] (2Dy), [Dy(SCS)2][Na(DME)3] (3Dy) and [Dy(SCS)2][K(2,2,2-cryptand)] (4Dy). For...