The Fascination of Polyoxometalate Chemistry

We are delighted to introduce this special issue of Inorganics. This themed issue is dedicated to polyoxometalates (POMs) as an outstanding class of oxo-cluster materials. Polyoxometalates have fascinated generations of researchers since the mid-18th-century, and they continue to attract promising young scientists all over the world. Since the first pioneering studies, the manifold structures and properties of POMs, have been the focus of interdisciplinary research synthetic/structural chemistry, biology, physics and theoretical chemistry. Moreover, polyoxometalates excel through outstanding compositional and structural diversity, which enables fine-tuning of their electronic properties, redox properties, and chemical stability along with robustness for the design of future applied devices. The growing family of polyoxometalates can be divided into two classes: transition-metal-substituted polyoxometalates (TMSPs) and lanthanide-substituted polyoxometalates (LnSPs). They currently attract particular interest due to their strong potential in the most challenging forefront research areas, e.g., water splitting, catalysis, magnetism, electronic materials and bio-medical applications. In the present themed issue, several research domains of polyoxometalate chemistry are covered by internationally renowned research groups in this topical field, ranging from synthesis/characterization and biological properties, through water oxidation catalysis and photochromic properties, to liquid crystal properties. The present special issue starts with a new report by William H. Casey and co-workers on the synthesis and crystal structure determination of a new polynuclear Ga(III)-oxyhydroxo cluster [1]. This compound extends the hitherto very short list of group 13 clusters (with Al 3+ and Ga 3+ cations). The newly discovered oxo-cluster contains 30 Ga(III) centers, and its structure was determined from single crystal X-ray diffraction techniques at the Advanced Light Source. The contribution of Juan M. Gutierrez-Zorrilla and co-workers [2], sheds light on a fascinating and versatile domain of polyoxometalate chemistry, namely the use of Keggin-type polyoxometalates XM12O40 n− (X = Si, Ge) as building-blocks and precursors for the design and synthesis of new OPEN ACCESS