A brief visit to the BeCl2/ZnCl2 system and the prediction of a new polymorph of ZnCl2

Reactions of zinc chloride with beryllium chloride in the molar ratios of 1:1 and 3:2 at T = 300°C in sealed ampoules lead to the formation of the two compounds Be1−xZnxCl2 (x = 0.563(2) and 0.489(3), respectively). Their composition and crystal structures were evidenced by single crystal X-ray structure analysis. Both compounds crystallize isotypic to β-BeCl2 in the tetragonal space group I41/acd, No. 142, tI96, with a = 10.7548(1), c = 19.4656(5) Å, V = 2251.50(7) Å3, Z = 32 at T = 100 K for the first and a = 10.7511(3), c = 19.2335(10) Å, V = 2223.1(2) Å3, Z = 32 at T = 100 K for the second compound. The positions of the Be atoms are mixed-occupied by Zn atoms. The compounds were additionally characterized by powder X-ray diffraction and infrared spectroscopy. Plots according to Vegard’s law allowed for extrapolation towards a neat ZnCl2 phase that would crystallize in the β-BeCl2 structure, which is the ZnI2 structure type. Quantum chemical calculations have confirmed that such a ZnCl2 modification would represent a true local minimum.

N-Heterocyclic Carbene-Supported Aryl- and Alk- oxides of Beryllium and Magnesium

Recently, we have witnessed significant progress with regard to the synthesis of molecular alkaline earth metal reagents and catalysts. To provide new precursors for light alkaline earth metal chemistry, molecular aryloxide and alkoxide complexes of beryllium and magnesium are reported. The reaction of beryllium chloride dietherate with two equivalents of 1,3-diisopropyl-4,5-dimethylimidizol-2-ylidine (sIPr) results in the formation of a bis(N-heterocyclic carbene) (NHC) beryllium dichloride complex, (sIPr)2BeCl2 (1). Compound 1 reacts with lithium diisopropylphenoxide (LiODipp) or sodium ethoxide (NaOEt) to form the terminal aryloxide (sIPr)Be(ODipp)2 (2) and alkoxide dimer [(sIPr)Be(OEt)Cl]2 (3), respectively. Compounds 2 and 3 represent the first beryllium alkoxide and aryloxide species supported by NHCs. Structurally related dimers of magnesium, [(sIPr)Mg(OEt)Brl]2 (4) and [(sIPr)Mg(OEt)Me]2 (5), were also prepared. Compounds 1-5 were characterized by single crystal X-ray diffraction studies, 1H, 13C, and 9Be NMR spectroscopy where applicable.

The coordination behaviour and reactivity of partially silicon based crown ethers towards beryllium chloride

The reaction of partially silicon based crown ethers with BeCl2 yields eight-membered Be–O-heterocycles, which are annulated by two six-membered Be–O-cycles.