Cyclic Polyvanadates Incorporating Template Transition Metal Cationic Species:  Synthesis and Structures of Hexavanadate [PdV₆O₁₈]^4-, Octavanadate [Cu₂V₈O₂₄]^4-, and Decavanadate [Ni₄V₁₀O₃₀(OH)₂(H₂O)₆]^4-

Abstract

Three types of heteropolyvanadates, [(C2H5)4N]4[PdV6O18] (1), [(C2H5)4N]4[Cu2V8O24] (2), and [(C6H5)4P]4[Ni4V10O30(OH)2(H2O)6] (3), were synthesized through the reaction between the [VO3]- anion and metal template cations of Pd(II), Cu(II), and Ni(II). The X-ray crystal structures of 1 (a = 29.952(4) A, b = 12.911(2) A, and c = 13.678(2) A, orthorhombic, space group Pca2(1) with Z = 4), 2 (a = 13.740(1) A, b = 22.488(2) A, c = 18.505(2) A, and beta= 94.058(2) degrees , monoclinic, space group P2(1)/n with Z = 4), and 3 (a = 12.333(2) A, b = 16.208(4) A, c = 16.516(3) A, alpha = 112.438(3) degrees , beta = 94.735(3) degrees , and gamma = 104.749(3) degrees , triclinic, space group P with Z = 1) demonstrate that the metal cationic species induced cyclic [VO3](n-)n (n = 6, 8, 10) ring formation and the cations are incorporated in the rings themselves. In the metal inclusion products, the cyclic vanadates act as macrocyclic ligands, in which the metal cationic species act as the templates. The cyclic vanadate is composed of tetrahedral VO4 units that share corners and incorporates a metal cationic species in the center of the molecules. The bowl-shaped complex 1 includes a Pd2+ cation that is coordinated by the oxygen donors of a boatlike hexavanadate ring. The diamagnetic complex 1 was characterized via 51V and 17O NMR spectroscopy. Complex 2 involves an octavanadate ring and two Cu2+, which are located on both sides of the mean plane as defined by the eight oxygen atoms that bridge the vanadium atoms. In the case of complex 3, the di-mu-hydroxo-bridged Ni2+ dimer with capped Ni2+ aqua ions is formed by hydrolysis to form the decavanadate ring, in which two of the tetrahedral vanadate units are not bonded to the Ni2+ core but supported by hydrogen bonds through the aqua-ligand in the capped Ni2+ cation. Complexes 1-3 in solution were clearly identified by their characteristic isotope patterns using ESI-MS studies.

Noble Metals in Polyoxometalates

“…The rigid structure in solution (no evidence of boat-chair interconversion) was confirmed by variable temperature 51 V NMR, 17 O NMR spectroscopy and was further characterized by ESI mass spectrometry. [9] Reaction of the heterometallic cuboidal clusters [Mo 3 À or pyridine) causes dissociation into the monomers with Pd-L coordination. [10] 2.1.3.…”

Formation of VV Lacunary Polyoxovanadates and Interconversion Reactions of Dodecavanadate Species

“…We are currently interested in the cyclic polyoxovanadate species, (VO 3 ) n n-, which are capable of coordination with cationic templates. [9] Metavanadate species have one-dimensional or cyclic structure, [10] which can act as a larger macrocyclic oxo-ligand to metal centers. An example includes the reduced decavanadate (Figure 1) which can be regarded as a dinuclear vanadyl complex with a macrocyclic octadecavanadate ligand.…”

High‐Nuclearity Silver Ethynide Clusters Assembled with Phosphonate and Metavanadate Precursors

“…(Et 4 N)VO 3 was synthesized by the literature method. [9] 1: tBuCCAg (0.095 g, 0.500 mmol) and AgBF 4 (0.098 g, 0.500 mmol) were dissolved in methanol (6 mL), and then (BzEt 3 N)Cl (0.011 g, 0.050 mmol) was added. After adding a 5 mL methanol solution of (Et 4 N)VO 3 (0.117 g, 0.500 mmol) and tBuPO 3 H 2 (0.069 g, 0.500 mmol), the resulting solution was kept under stirring for 15 min, and after 30 min a clear orange-red solution was obtained.…”