Abstract
The title compound, [Ni(C(10)H(8)O(4))(C(16)H(20)N(4))(H(2)O)(2)](n), contains Ni(II) cations octa-hedrally surrounded within an [O(4)N(2)] coordination set. The cations are linked by 4-(carb-oxy-eth-yl)benzoate (ceb) and 1,4-bis-(pyridin-4-ylmeth-yl)piperazine (bpmp) ligands into tri-periodic diamondoid (dia) networks. The fivefold inter-penetrated dia networks are held into the crystal structure by means of O-H⋯O hydrogen bonding between bound water mol-ecules and unligated carboxyl-ate O atoms of the ceb ligands.