Anisotropic Polyoxometalate Cages Assembled via Layers of Heteroanion Templates

Abstract

The synthesis of anisotropic redox-active polyoxometalates (POMs) that can switch between multiple states is critical for understanding the mechanism of assembly of structures with a high aspect ratio, as well as for their application in electronic devices. However, a synthetic methodology for the controlled growth of such clusters is lacking. Here we describe a strategy, using the heteroanion-directed assembly, to produce a family of 10 multi-layered, anisotropic POM cages templated by redox-active pyramidal heteroanions with the composition [W 16 Mo 2 O 54 (XO 3 )] n − , [W 21 Mo 3 O 75/76 (XO 3 ) 2 ] m − , and [W 26 Mo 4 O 93 (XO 3 ) 3 ] o − for the double, triple, and quadruple layered clusters, respectively. It was found that the introduction of reduced molybdate is essential for self-assembly and results in mixed-metal (W/Mo) and mixed-valence (W VI /Mo V ) POM cages, as confirmed by an array of analytical techniques. To probe the archetype in detail, a tetrabutyl ammonium (TBA) salt derivative of a fully oxidized two-layered cage is produced as a model structure to confirm that all the cages are a statistical mixture of isostructures with variable ratios of W/Mo. Finally, it was found that multilayered POM cages exhibit dipolar relaxations due to the presence of the mixed valence W VI /Mo V metal centers, demonstrating their potential use for electronic materials.

Semi-automatic scheme for early-stage material search: developing solvent-solubility prediction of tetraphenylporphyrin derivatives securing chemical-space coverage

“…A molecule 𝑚 is considered 'covered' if 𝑚 or one of its neighbor molecules has been already selected. The expression (11) represents that we equivocally handled all molecules, each with a weight of 1. Therefore, 𝑊 equals to the total number of MOLSPACE ( 𝑁𝑀𝑂𝐿 ).…”

“…Furthermore, the advantages and limitations of the proposed method are discussed herein. (11)(12)(13)(14)(15). For GENERATED, molecules are listed in order of priority (11 is highest priority).…”

“…b Chemical structures of molecules in ACCESSIBLE (1-10). c Five synthesized TPP derivatives with highest priorities from GENERATED(11)(12)(13)(14)(15). For GENERATED, molecules are listed in order of priority (11 is highest priority).…”

Hexameric Lanthanide–Organic Capsules with Tertiary Structure and Emergent Functions

“…Chemists are always amazed by the marvelous hierarchical structures in nature, where multiple basic building units (e.g., proteins or nucleotides) stepwise self-assemble into complex macromolecules with emergent functions arising from the collective behaviors of aggregated components. , Over the past decades, metal-directed self-assembly has become a powerful approach in designing sophisticated functional supramolecular architectures. − In virtue of the coordination behavior (i.e., coordination numbers and geometries) analogous to that of metal ions, anion-templated synthesis or anion-directed self-assembly has also been very successful in the design of unique supramolecular structures. − However, the properties and functions of those artificial assemblies are mainly derived from their primary and secondary structures. While many metallasupramolecular complexes are positively charged, the existence of counteranions is often overlooked due to their strong solvation in solution or high disorder in the solid state.…”

Uncoordinated‐substituents‐induced zinc(II) coordination polymers exhibiting multifunctional fluorescent sensing activity for cations, anions and organochlorine pesticides

“…Coordination polymers (CPs) are a kind of inorganic-organic hybrid materials which are self-assembled by metal centers and organic ligands through coordination bonds. [1][2][3] Because of its structural diversity and excellent chemical stability, it has potential application prospects in catalysis, [4] gas adsorption and separation, [5][6][7] electrochemistry [8,9] and other fields. The main factors affecting the formation of CPs are metal ions, types of organic ligands, coordination modes of carboxylic acids and so on.…”