Formation and Properties of the Trichloroberyllate Ion.

The activation of C-Cl bonds in dichloromethane and chloroform was observed by BeCl in the presence of PMe and PCy. This leads to the formation of [MePCHCl]Cl and [CyPCHCl][BeCl]. The latter compound is the first example of a tricoordinated beryllium species with nonbulky ligands and proof of the existence and stability of the long-predicted [BeCl] ion. In analogy to the isoelectronic BCl, the trichloroberyllate anion exhibits Lewis acidic behavior toward electron-pair donors and was probed for the electronic and steric influence of the Lewis base. [BeCl] can also act as a chloride ion donor or acceptor, leading to the formation of neutral phosphane adducts to BeCl and [BeCl]. The existing equilibria between these species were investigated and showed high chloride mobility.