Crystal structure of di-mu-aqua-mu-(pyrazine N,N '-dioxide)-kappa O-2:O-bis(diaquasodium) tetraphenylborate dihydrate pyrazine N,N '-dioxide monosolvate

The search for novel lanthanide coordination networks using pyrazine N,N'-dioxide (pzdo, C4H4N2O2) as a structure-directing unit, led to the synthesis and the structure determination of the title compound, [Na-2(C4H4N2O2)(H2O)(6)]-[B(C6H5)(4)](2)center dot C4H4N2O2 center dot 2H(2)O. The crystal structure is comprised of discrete [{Na(H2O)(2)}(2)(mu-H2O)(2)(mu-pzdo)](2+) cations and tetraphenylborate anions, as well as pzdo and H2O solvent molecules. The dinuclear cation is located about a twofold rotation axis, and the symmetry-related Na-I atoms display a distorted square-pyramidal coordination sphere defined by two O atoms of terminal water ligands, two O atoms of bridging water ligands and one O atom of a bridging pzdo ligand. In the crystal, O-H center dot center dot center dot O hydrogen bonds link the dinuclear cation and solvent pzdo molecules (point-group symmetry 1) into rectangular grid-like layers parallel to the be plane. Additional C-H center dot center dot center dot O,O-H center dot center dot center dot O,C-H center dot center dot center dot pi and O-H center dot center dot center dot pi interactions link the anion and solvent water molecules to the layers. The layers are further linked into a three-dimensional network through a combination of C-H center dot center dot center dot pi and O-H center dot center dot center dot pi hydrogen bonds involving the tetraphenylborate anion.