Antimonato polyoxovanadates with structure directing transition metal complexes: pseudopolymorphic {Ni(dien)2}3[V15Sb6O42(H2O)]·nH2O compounds and {Ni(dien)2}4[V16Sb4O42(H2O)].

Three new poloxovanadates were synthesized under solvothermal conditions and were structurally characterized. The two compounds with composition {Ni(dien)(2)}(3)[V(15)Sb(6)O(42)(H(2)O)]·nH(2)O (n = 12 and 8; dien = bis(2-aminoethyl)amine or diethylenetriamine) are pseudopolymorphs crystallizing in different space groups. The compounds were obtained by applying identical reaction slurries but using different reaction temperatures. Both compounds feature the [V(15)Sb(6)O(42)(H(2)O)](6-) anion which is the antimony analogue to the single molecule magnet [V(15)As(6)O(42)(H(2)O)](6-). Crystal data: 1 tetragonal space group P4, a = 46.9378(3), c = 16.51300(10) Å and V = 36380.7(4) Å(3). 2 rhombohedral space group R3c with a = 23.0517(4), c = 28.6216(5) Å and V = 13171.3(4) Å(3). In 1 several unusual short inter-cluster Sb···O contacts lead to the formation of three different super-clusters with composition V(60)Sb(24)O(168). The 12 unique {Ni(dien)(2)}(2+) complexes adopt all three possible configurations. In 2 the special arrangement of the {Ni(dien)(2)}(2+) complexes around the cluster anion prevents inter-cluster Sb···O contacts. The main structural motif of the third compound {Ni(dien)(2)}(4)[V(16)Sb(4)O(42)(H(2)O)] (3) is the [V(16)Sb(4)O(42)(H(2)O)](8-) cluster anion consisting of two perpendicular eight-membered rings of VO(5) pyramids. Two additional VO(5) polyhedra are located on opposite sides. Crystal data: 3 triclinic space group P1 = 13.5159(4), b = 14.2497(5), c = 14.9419(4) Å, α = 98.322(2), β = 114.080(2), γ = 110.130(2)° and V = 2326.35(12) Å(3).