trans-Diaqua­bis{1,3-bis­[5-(2-pyrid­yl)-2H-tetra­zol-2-yl]propane}zinc(II) bis­(perchlorate)

The Zn(II) ion in the title compound, [Zn(C(15)H(14)N(10))(H(2)O)(2)](ClO(4))(2), lies on a centre of symmetry. The distorted N(4)O(2) octa­hedral coordination environment around the Zn atom is composed of two 1,3-bis­[5-(2-pyrid­yl)-2H-tetra­zol-2-yl]propane ligands (L1) and two water mol­ecules, coordinated in trans positions. The ligand acts as a typical bidentate chelating ligand through one of its 2-pyridyl-2H-tetra­zole units, forming a five-membered Zn—N—C—C—N metallacycle with a small N—Zn—N bite angle [77.40 (8)°]. The other 2-pyridyl-2H-tetra­zole unit remains uncoordinated. The average Zn—N distance (2.156 Å) is somewhat longer than the distance between the Zn(II) center and the aqua ligand [2.108 (2) Å]. The coordinated pyrid­yl-tetra­zoyl rings are quasi-coplanar, making a dihedral angle of 1.9 (2)°, while the uncoordinated rings show a larger inter­planar angle of 21.3 (2)°. The flexible propane spacer displays a zigzag chain. Inter­molecular O—H⋯N and O—H⋯O inter­actions result in two-dimensional polymeric structures parallel to (100). Two C atoms of the spacer are disordered over two positions, with site occupancy factors of ca 0.85 and 0.15.