Lead(II) Tetracyanidoborates with Pb 2 O 2 Dimers Embedded in Network Structures

First lead(II) tetracyanidoborates were synthesized and the crystal structures of [Pb-2(H2O)(4){B(CN)(4)}(4)] (1) and [Pb-2(O2CCH3)(2){B(CN)(4)}(2)(C2H5OH)(2)] (2) were determined by X-ray diffraction. Both compounds contain dinuclear centrosymmetric Pb2O2 cores. The Pb(II) ions in both compounds have heteroleptic holodirected coordination environments constituted by three O and five N atoms (O3N5) in 1 different from that in 2, which is constituted by four O and four N atoms (O4N4). In 1 the bridging O atoms of the Pb2O2 unit belong to the water ligands, whereas in 2 one O atom of each of the two acetate ligands has the bridging functionality whereas the second one is terminally bonded, i. e. the acetate ligand coordinates in a mu(2)-eta(2):eta(1) fashion. In 2, all four N atoms of the tetracyanidoborate anion are coordinated to neighboring Pb2O2 units, whereas in 1 free cyanido groups exist. Nevertheless, in both structures the dinuclear Pb units are three-dimensionally interconnected, i. e. they are Pb(II) coordination networks. On heating compound 1 loses the aqua ligands and anhydrous Pb[B(CN)(4)](2) forms.