Two Compounds Containing the Mixed Germanium–Vanadium Polyoxothioanion [V₁₄Ge₈O₄₂S₈]¹²⁻

Abstract

The variety of microporous polyhedral framework solids has increased severely in the last years.[1] The largest classes of microporous materials are still aluminosilicates (Al-O-Si) and aluminophosphates (Al-O-P) as well as their isomorphic substituted forms. These compounds have been studied extensively because of their interesting properties and applications in industrial processes as, for instance, catalysts and ion-exchange materials. A promising strategy for the synthesis of new open-framework materials with elements others than Al or Si is to connect larger building units like clusters in vanadates and molybdates or secondary building units (SBUs) in large-pore indium sulfides. [2][3][4][5][6][7] The interconnection of polyoxometal building blocks like polyoxovanadates by means of covalent bonds could create new porous materials with ultralow framework densities and high porosity. The catalytic or photochemical reactivity of such transition-metal-based materials could be enhanced relative to that of Si-or Al-containing materials. Vanadium is of particular interest because it shows a flexible coordination behavior as well as a great variety of valence states. VO 4 tetrahedra, VO 5 square pyramids, and VO 6 octahedra are often observed as primary building units in polyoxovandate compounds.[8] These building units are able to form larger aggregates and/or clusters by condensation of the polyhedra. The clusters or aggregates may then be joined through metal coordination complexes to create three-dimensional framework structures. During the last years a number of pure and mixed vanadates like vanadiumborates, -arsenates, -germanates, and -phosphates with organic and inorganic counterions have been prepared. [9][10][11][12][13][14] In our investigations we attempted to incorporate sulfur and germanium in anionic vanadium clusters in order to enhance the structural diversity of the building units and to generate possible porous compounds. Here we report the synthesis and characterization of the two new mixed Ge/V polyoxothio compounds (dien-H 3 )

Controlling Nucleation and Crystal Growth of a Distinct Polyoxovanadate Cluster: An In Situ Energy Dispersive X‐ray Diffraction Study under Solvothermal Conditions

“…It is documented that the amine reduces V V to V IV of the vanadium source NH 4 VO 3 30. 31, 32 In addition, Sb 2 O 3 is dissolved in the basic solutions providing the species for crystallization of the products.…”

“…During the last few years, more attention was drawn to chemical reactions under in situ conditions to acquire a detailed picture about the reaction and crystallization mechanisms 1–28. Since few years, we are synthesizing polyoxovanadates (POVs) and especially POVs modified by heteroatoms (As29, Ge30, Sb31, 32) under solvothermal conditions. The range of potential applications of POVs covers areas form medicine to catalysis 33.…”

Semimetal-functionalised polyoxovanadates

“…As it was noted, ''the interconnection of polyoxometal building blocks like polyoxovanadates by means of covalent bonds could create new porous materials with ultralow framework densities and high porosity''. 99 In view of the structural arrangement and organisation of the extended solid-state structures discussed above, it appears highly desirable to explore the role of the SiPOV-based networks as microporous molecular materials resembling zeolites or molecular sieves, e.g., for catalytic performance, gas storage, and ion exchange. building blocks.…”

In‐situ Complex and Sb–N Bond Formation in an Antimonato Polyoxovanadate Reaction System

“…Selected examples are [Mn 4 V 4 O 17 (OAc) 3 ] 3– or ( n Bu 4 N) 3 [Co(AcO)V 4 O 12 ] . The polyoxovanadate cluster can also be modified by integration of main group semi‐metals leading to compounds like [Cd(en) 3 ][Cd(en)] 2 {[Cd(en)] 2 [V 12 Ge 8 VO 42 (OH) 6 ]} · 10H 2 O, [V 14 Ge 8 O 42 S 8 ] 12– , (V 15 (H 2 pdn) 3 (Hpdn)[V 15 Si 6 O 42 (OH) 6 (Cl)] · n H 2 O ( n = 7–10) (pdn = 1,3‐propanediamine), (H 1.5 pdn) 6 [{H 2 V 15 Si 6 O 48 (Cl)}(VO 2 ) 2 ] · 4H 2 O, K 6 [V 15 As 6 O 42 (H 2 O)] · 8H 2 O, or [Co(en) 3 ][{Co(en) 2 } 2 V 15 As 6 O 42 ] · 4H 2 O (en = ethylenediamine) …”