A Novel Series of Materials Composed of Arrays of Vanadium Oxide Container Molecules, {V₁₈O₄₂(X)} (X = H₂O, Cl^-, Br^-):  Synthesis and Characterization of [M₂(H₂N(CH₂)₂NH₂)₅][{M(H₂N(CH₂)₂NH₂)₂}₂V₁₈O₄₂(X)]· 9H₂O (M = Zn, Cd)

Abstract

The synthesis and characterization of the novel systems [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(H(2)O)].9H(2)O (1), [Cd(2)(H(2)N(CH(2))(2)NH(2))(5)][(Cd(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Br)].9H(2)O (2), and [Zn(2)(H(2)N(CH(2))(2)NH(2))(5)][(Zn(H(2)N(CH(2))(2)NH(2))(2))(2)V(18)O(42)(Cl)].9H(2)O (3) have been described. These materials represent a new class of solids that have been prepared by combining conventional coordination compounds with spherical polyoxovanadate clusters. The isomorphous structures of these hybrid solids consist of two-dimensional arrays of container cluster molecules [V(18)O(42)(X)] (X = H(2)O, Br-, Cl-) interlinked by the transition metal complex moieties [M(H(2)N(CH(2))(2)NH(2))(2)] (M = Zn, Cd). These compounds contain an unprecedented complex cation, [M(2)(H(2)N(CH(2))(2)NH(2))(5)](4+). Crystal data for 1: C(9)H(46)N(9)O(26)V(9)Zn(2), monoclinic space group P2(1)/m (No. 11), a = 12.3723(7) A, b = 20.9837(11) A, c = 15.8379(8) A, beta = 97.3320(10) degrees, Z = 4.

Hybrid Inorganic–Organic 1D and 2D Frameworks with [As6V15O42]6– Polyoxoanions as Building Blocks

“…Moreover, the construction of these new materials may facilitate the formation of unexpected species [16] 4+ cations observed during the course of this work. Linking discrete POMs to build solid-state materials is of great interest not only from a structural point of view, but also because they are potentially interesting for applications in different areas.…”

“…During the past few years, a lot of research efforts have been focused on the application of secondary transition-metal complexes (TMCs) as bridging ligands linking POM clusters into 1-, 2-, and 3D networks under hydrothermal conditions. [10][11][12][13] Compounds [{Cu(enMe) 2 } 7 -{V 16 [15] are recent examples. The former is made up of the hexadecavanadate clusters linked by the [Cu(enMe) 2 ] 2+ complex fragments into a rare 3D open framework, while the latter exhibited a novel 2D Mo-V-O polyoxometalate with two types of cobalt complex fragments as bridges.…”

“…More recently, Khan et al reported three novel 2D frameworks that consist of spherical {V 18 O 42 (X)} shells linked by bridging {M(en) 2 } groups (X = H 2 O, Br -, Cl -; M = Zn, Cd). [16] An important subclass of the large POM family is As-V-O clusters with arsenic and vanadium in low oxidation states, which often act as cryptates encapsulating neutral molecules or anions. Since the first As-V-O cluster K 6 [As 6-V 15 [17] a number of As-V-O clusters have been synthesized, [18][19][20][21][22][23][24][25][26][27] (X = SO 3 2-or SO 4 2-), [20] [17] It consists of fifteen VO 5 square pyramids and three handlelike As 2 O 5 units.…”

“…The two terminal N13 and N13A atoms of bridging dien exhibit strong attachment to the Zn3 and Zn3A atoms, respectively, with Zn-N distances of 2.036(18) Å, while the middle N14 atom occupies the central site of the binuclear cation and exhibits weak attachment to both Zn3 and Zn3A atoms with Zn-N distances of 2.398(3) Å, which are much longer than the usual Zn-N values (about 1.90-2.20 Å) observed in many reported studies. [16,35,36] Such a coordination mode between the Zn atoms and the bridging dien ligand is peculiar. The Zn3-O distance [2.430(2) Å] and the bond valence sum [30] value (0.17) identify the O atom coordinated to the Zn3 center as H 2 O (denoted as OW4 in this paper).…”

“…These positions of the bands and their assignments of 1-3 are consistent with literature reports. [16,24,37] The thermogravimetric analyses were carried out in flowing N 2 with a heating rate of 10°C·min -1 in the temperature range 30-1000°C for compounds 1-3 ( Figure 10). Three distinct weight-loss stages are observed on the TGA curve of compound 1.…”