Oxo-Replaced Polyoxometalates: There Is More than Oxygen

The presence of oxo-ligands is one of the main required characteristics for polyoxometalates (POMs), although some oxygen ions in a metallic environment can be replaced by other nonmetals, while maintaining the POM structure. The replacement of oxo-ligands offers a valuable approach to tune the charge distribution and connected properties like reducibility and hydrolytic stability of POMs for the development of tailored compounds. By assessing the reported catalytic and biological applications and connecting them to POM structures, the present review provides a guideline for synthetic approaches and aims to stimulate further applications where the oxo-replaced compounds are superior to their oxo-analogues. Oxo-replacement in POMs deserves more attention as a valuable tool to form chemically activated precursors for the synthesis of novel structures or to upgrade established structures with extraordinary properties for challenging applications.

Discovery of novel β-turn mimetic-based peptides as novel quorum sensing inhibitors of gram-negative bacteria

To date, a very limited number of peptides reported as quorum sensing inhibitors. Herein, we report the synthesis and evaluation of a series of β-turn mimetic-based peptides as potent quorum sensing inhibitors and antibiofilm formation. In this series, peptides P1, P4, and P5 showed very promising anti-quorum sensing activity on lasB-gfp reporter strain of Pseudomonas aeruginosa without affecting bacterial growth. Under our condition, these compounds also showed good anti-violacein production of Chromobacterium violaceum. In terms of antibiofilm formation, except P5, two β-turn mimetic-based peptides P1 and P4 showed maximum inhibition of 80% total biomass of Pseudomonas aeruginosa. This report provides the first β-turn mimetic-based scaffold for future drug development.

Azines: synthesis, structure, electronic structure and their applications

Azines (2,3-diaza-1,3-butadienes): structure, electronic structure, tautomerism, and their applications in organic synthesis, medicinal chemistry and materials chemistry.

Ln(iii)-Containing polyoxomolybdates based on β-{Mo8O28}: microwave synthesis and optical and magnetic properties

The reactant mother liquor can be obtained by 600 watt microwave irradiation for 15 minutes. Under ultraviolet irradiation, these two compounds can undergo the photochromic process, and the fading process can occur after the ultraviolet irradiation was turned off.

Theoretical studies on the chiral polyoxoanions [P2Mo18O62]6− and [PMo9O31(OH2)3]3− with histidine: chiral inversion and chiral induction

Theoretical studies on the chiral polyoxoanions [P₂Mo₁₈O₆₂]⁶⁻ and [PMo₉O₃₁(OH₂)₃]³⁻ with histidine: Chiral inversion and chiral induction.

Microwave assisted synthesis of a mono organoimido functionalized Anderson polyoxometalate

The synthesis of an aliphatic organoimido functionalized polyoxometalate has been achieved through a microwave assisted reaction protocol in the absence of any activating reagents.

Synthesis and structural characterization of BINOL-modified chiral polyoxometalates

Chiral ligand-modified polyoxometalates (POMs) R-I and S-I were successfully synthesized by the introduction of BINOL into the dititanium-substituted POM.

Design, synthesis and biological evaluation of novel unsymmetrical azines as quorum sensing inhibitors

In this report, novel unsymmetrical azines have been designed and synthesised by using one pot approach. Further, they were evaluated as quorum sensing inhibitors.

Self assembly of carboxylate/alcoholate functionalized ring-shape phosphomolybdates

Carboxylate and alcoholate ligands were covalently attached to a [HPMo₆O₂₁]²⁻ cluster to generate a series of inorganic–organic hybrid phosphomolybdates.

Functionalization and post-functionalization: a step towards polyoxometalate-based materials

Polyoxometalates (POMs) have remarkable properties and a great deal of potential to meet contemporary societal demands regarding health, environment, energy and information technologies. However, implementation of POMs in various functional architectures, devices or materials requires a processing step. Most developments have considered the exchange of POM counterions in an electrostatically driven approach: immobilization of POMs on electrodes and other surfaces including oxides, embedding in polymers, incorporation into Layer-by-Layer assemblies or Langmuir-Blodgett films and hierarchical self-assembly of surfactant-encapsulated POMs have thus been thoroughly investigated. Meanwhile, the field of organic-inorganic POM hybrids has expanded and offers the opportunity to explore the covalent approach for the organization or immobilization of POMs. In this critical review, we focus on the use of POM hybrids in selected fields of applications such as catalysis, energy conversion and molecular nanosciences and we endeavor to discuss the impact of the covalent approach compared to the electrostatic one. The synthesis of organic-inorganic POM hybrids starting from bare POMs, that is the direct functionalization of POMs, is well documented and reliable and efficient synthetic procedures are available. However, as the complexity of the targeted functional system increases a multi-step strategy relying on the post-functionalization of preformed hybrid POM platforms could prove more appealing. In the second part of this review, we thus survey the synthetic methodologies of post-functionalization of POMs and critically discuss the opportunities it offers compared to direct functionalization.

Hybrid polyoxometalates: Keggin and Dawson silyl derivatives as versatile platforms

A new series of polyoxometalate-based hybrids has been synthesized. These covalently linked organic-inorganic materials represent valuable elementary building blocks ready for postfunctionalization, using classical organic reactions and couplings. This approach is exemplified by the grafting of an organic chromophore via a Sonogashira coupling.