Di-μ-nitrato-bis(μ-octaethyl pyrophosphoramide)bis[aquadinitratocalcium(II)]

Abstract

The title compound, di-μ-nitrato-κ3 O,O′:O;O:O,O′-bis(μ-octaethyl pyrophosphoramide-κ2 O:O′)bis[aquabis(nitrato-κ2 O,O′)calcium(II)], [Ca2(NO3)4(C16H40N4O3P2)2(H2O)2] was obtained as a side product during the work up of the synthesis of octaethyl pyrophosphoramide and represents the first structurally characterized complex of this ligand. The compound crystallizes in the monoclinic space group P21/n and the asymmetric unit contains one pyrophosphoramide molecule and one Ca2+ ion coordinated to two nitrate ions and one water molecule. The complex exists as a dimer with a centre of inversion located between two eight-coordinate calcium(II) centres, which are bridged by two nitrate ions and two octaethyl pyrophosphoramide ligands. Each Ca2+ cation is also coordinated to a further nitrate anion, acting as a bidentate ligand, and a water molecule. The complexes stack parallel to the a axis and are held in place by a network of intermolecular O—H...O hydrogen bonds also running parallel to a.