Carboxylic Acid Ester Adducts of Beryllium Chloride and Their Role in the Synthesis of Beryllium Nitrates

To investigate the synthetic route towards anhydrous Be(NO3)2 (2), beryllium esterates [BeCl2(MeOAc)2] (4a), [BeCl2(EtOAc)2] (4b), [BeCl2(iPrOAc)2] (4c), [BeCl2(MeOForm)2] (4d), [BeCl2(EtOForm)2] (4e), and [BeCl2(iPrOForm)2] (4f) were synthesized and spectroscopically characterized. Additionally, the crystal structure of [BeCl2(MeOAc)2] (4a) was determined and DFT calculations on these adducts were performed. These four‐coordinate beryllium complexes react, in contrast to BeCl2, readily with N2O4 under the evolution of NOCl to form ester adducts of Be(NO3)2 (5), which react with excess amounts of N2O4 to afford known (NO)2[Be(NO3)4] (1). However, it is not possible to completely remove the carboxylic acid esters from nitrosyl salt 1. Therefore, the thermal decomposition leads to the formation of mixtures of beryllium nitrates 2 and 5. Furthermore it could be shown that this mixture decomposes even at ambient temperature slowly to [Be4O](NO3)6 (3). Carboxylic acid esterates of beryllium chloride were synthesized and characterized. These compounds react readily with N2O4 to form beryllium nitrates and subsequently (NO)2[Be(NO3)4]. The consecutive thermal decomposition of the nitrosyl salt gives a mixture of different beryllium nitrates.