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Special Issue "Polyoxometalates and Polyoxometalate-Based Systems"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Inorganic Chemistry".

Deadline for manuscript submissions: 31 December 2018

Special Issue Editor

Guest Editor
Dr. Santiago Reinoso

Institute for Advanced Materials (INAMAT), Universidad Pública de Navarra, Pamplona, Spain
E-Mail
Interests: Synthetic Inorganic Chemistry; Polyoxometalates; Coordination Chemistry of Transition Metals and Rare Earths; Supramolecular Architectures; Crystallography and Single-Crystal Phase Transitions

Special Issue Information

Dear Colleagues,

Polyoxometalates are a class of molecules that have fascinated researchers for decades. Despite being first described centuries ago, this type of anionic metal–oxygen clusters continues to represent a highly vibrant research domain because of their unmatched collection of versatile properties. The vast polyoxometalate family encompasses molecular species with very diverse sizes (from small dimetalates to clusters comparable to small proteins) and manifold structures (often with highly symmetric topologies) that tend to show rich solution equilibria, significant chemical and thermal stability, and the ability to act as proton–electron sinks thanks to their fast and reversible proton-coupled redox processes. These properties can usually be fine-tuned at the atomic level through systematic compositional modifications performed in the cluster skeleton. Moreover, the possibility of generating vacant metallic sites in a controlled manner allows polyoxometalates to be used as robust, fully-inorganic polydentate ligands toward a range of electrophilic moieties (e.g., transition-metal cations, rare earths, p-block organoderivatives, etc.), thus paving the way for endowing the clusters with tailored additional properties brought by such electrophiles. The combination of all these features confers an intrinsic multifunctional nature on polyoxometalates that places these clusters at the frontier between an exceptionally wide range of scientific disciplines, such as inorganic chemistry, physics, crystallography, catalysis, biology or medicine. As such, they offer virtually endless options for future applied developments in these areas, and hence, they are continuously selected as the active molecule of choice for constructing new advanced materials upon integration with, for example, polymers, oxides, or carbonaceous supports. This Special Issue is intended to focus on the most recent advances in polyoxometalate chemistry and polyoxometalate-based systems by covering different aspects from fundamentals (synthetic methods, reactivity, spectroscopic or spectrometric studies, structures, mechanistic insights) to potential applications (redox and acid-base catalysis, photo- and electrochemistry, magnetism, electronics, optics, bio-medicine, energy conversion and storage, sorption and separation, environmental remediation). Full papers, communications, and reviews on these topics are welcome.

Dr. Santiago Reinoso
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Polyoxometalates and derivatives
  • Synthesis and reactivity
  • Spectroscopic and spectrometric studies
  • Crystallochemistry
  • Computational modeling
  • Redox and acid-base catalysis
  • Photo- and electrochemistry
  • Magnetism
  • Electronics and optics
  • Batteries and capacitors
  • Sorption and separation
  • Environment
  • Bio-medical applications

Published Papers (1 paper)

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Research

Open AccessArticle Thermochemical Measurements of Alkali Cation Association to Hexatantalate
Molecules 2018, 23(10), 2441; https://doi.org/10.3390/molecules23102441
Received: 6 September 2018 / Revised: 18 September 2018 / Accepted: 19 September 2018 / Published: 24 September 2018
PDF Full-text (615 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Ion association is an important process in aqueous dissolution, precipitation, and crystallization of ionic inorganic, organic, and biological materials. Polyoxometalates (POMs) are good model compounds for understanding the complex relationships between lattice energy, ion-pairing in solution, and salt solubility. Here we perform calorimetric
[...] Read more.
Ion association is an important process in aqueous dissolution, precipitation, and crystallization of ionic inorganic, organic, and biological materials. Polyoxometalates (POMs) are good model compounds for understanding the complex relationships between lattice energy, ion-pairing in solution, and salt solubility. Here we perform calorimetric measurements to elucidate trends in cluster stability, lattice energy, and ion-pairing behavior studies of simple hexatantalate salts in neat water, parent hydroxide solutions, and molybdate melts, extending previous studies on the isostructural hexaniobates. High temperature calorimetry of alkali salts of hexatantalate reveals that the enthalpies of formation from oxides of the K, Rb, and Cs salts are more similar to each other than they are for their niobate analogues and that the tantalate cluster is energetically less stable than hexaniobate. Aqueous dissolution calorimetry reveals that the cesium salt of hexatantalate has a similar concentration dependence on its dissolution enthalpy to that of hexaniobate. However, unlike rubidium hexaniobate, rubidium hexatantalate also exhibits increased concentration dependence, indicating that hextantalate can undergo increased ion-pairing with alkali salts other than cesium, despite the dilute environments studied. Dissolution enthalpies of POM salts in the parent alkali hydroxides shows that protonation of clusters stabilizes lattices even more than the strongly associating heavy alkali cations do. Additionally, neither weak nor strong lattice ion associations necessarily correlates with respectively high or low aqueous solubility. These studies illuminate the importance of considering ion-pairing among the interrelated processes in the aqueous dissolution of ionic salts that can be extended to serving as a model of cation association to metal oxide surfaces. Full article
(This article belongs to the Special Issue Polyoxometalates and Polyoxometalate-Based Systems)
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