[en] Template‐mediated synthesis is a powerful approach to build a variety of functional materials and complex supramolecular systems. However, the systematic study of how templates structurally evolve from basic building blocks, and then affect the templated self‐assembly, is critical to understanding and utilizing the underlying mechanism, to work towards designed assembly. Here we describe the templated self‐assembly of a series of gigantic Mo Blue (MB) clusters 1–4 using l‐ornithine as a structure‐directing ligand. We show that by using l‐ornithine as a structure director, we can form new template⊂host assemblies. Based on the structural relationship between encapsulated templates of {Mo${}_8$} (1), {Mo${}_{17}$} (2) and {Mo${}_{36}$} (4), a pathway of the structural evolution of templates is proposed. This provides insight into how gigantic Mo Blue cluster rings form and could lead to full control over the designed assembly of gigantic Mo‐blue rings. (© 2019 The Authors. Published by Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

[en] The assembly of nanoscale polyoxometalate (POM) clusters has been dominated by the highly reduced icosahedral {Mo${}_{132}$} "browns" and the toroidal {Mo${}_{154}$} "blues" which are 45 % and 18 % reduced, respectively. We hypothesised that there is space for a greater diversity of structures in this immediate reduction zone. Here we show it is possible to make highly reduced mix-valence POMs by presenting new classes of polyoxomolybdates: [Mo${}^V$${}_{52}$Mo${}^{VI}$${}_{12}$H${}_{26}$O${}_{200}$]${}^{42-<!--\; ???\; -->}$ {Mo${}_{64}$ and [Mo${}^V$${}_{40}$Mo${}^{VI}$${}_{30}$H${}_{30}$O${}_{215}$]${}^{20-<!--\; ???\; -->}$ {Mo${}_{70}$, 81 % and 57 % reduced, respectively. The {Mo${}_{64}$} cluster archetype has a super-cube structure and is composed of five different types of building blocks, each arranged in overlayed Archimedean or Platonic polyhedra. The {Mo${}_{70}$} cluster comprises five tripodal {Mo${}^V$${}_6$} and five tetrahedral {Mo${}^V$${}_2$Mo${}^{VI}$${}_2$} building blocks alternatively linked to form a loop with a pentagonal star topology. We also show how the reaction yielding the {Mo${}_{64}$} super-cube can be used in the enrichment of lanthanides which exploit the differences in selectivity in the self-assembly of the polyoxometalates. (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH)

[en] The construction of pure-inorganic framework materials with well-defined design rules and building blocks is challenging. In this work, we show how a polyoxometalate cluster with an integrated pore, based on [P${}_8$W${}_{48}$O${}_{184}$]${}^{40-<!--\; ???\; -->}$ (abbreviated as {P${}_8$W${}_{48}$}), can be self-assembled into inorganic frameworks using silver ions, which both enable reactions on the cluster as well as link them together. The {P${}_8$W${}_{48}$} was found to be highly reactive with silver ions resulting in the in situ generation of fragments, forming {P${}_9$W${}_{63}$O${}_{235}$} and {P${}_{10}$W${}_{66}$O${}_{251}$} in compound (1) where these two clusters co-crystallize and are connected into a POMZite framework with 11 Ag${}^{+}$ ions as linkers located inside clusters and 10 Ag${}^{+}$ linking ions situated between clusters. Decreasing both the concentration of Ag${}^{+}$ ions, and the reaction temperature compared to the synthesis of compound (1), leads to {P${}_8$W${}_{51}$O${}_{196}$} in compound 2 where the {P${}_8$W${}_{48}$} clusters are linked to form a new POMZite framework with 9 Ag${}^{+}$ ions per formula unit. Further tuning of the reaction conditions yields a cubic porous network compound (3) where {P${}_8$W${}_{48}$} clusters as cubic sides are joined by 4 Ag${}^{+}$ ions to give a cubic array and no Ag${}^{+}$ ions were found inside the clusters. (© 2019 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

[en] Significant successes have been made over recent years in preparing co-ordination framework polymers that show macroscopic material properties, but in the vast majority of cases this has been achieved with d-block metal-based systems. Lanthanide co-ordination frameworks also offer attractive properties in terms of their potential applications as luminescent, non-linear optical and porous materials. However, lanthanide-based systems have been far less studied to date than their d-block counterparts. One possible reason for this is that the co-ordination spheres of lanthanide cations are more difficult to control and, in the absence of design strategies for lanthanide co-ordination frameworks, it is significantly more difficult to target materials with specific properties. However, this article highlights some of the exciting possibilities that have emerged from the earliest investigations in this field with new topological families of compounds being discovered from relatively simple framework components, including unusual eight, seven and five-connected framework systems. Our own research, as well as others, is leading to a much greater appreciation of the factors that control framework formation and the resultant observed topologies of these polymers. As this understanding develops targeting particular framework types will become more straightforward and the development of designed polyfunctional materials more accessible. Thus, it can be seen that lanthanide co-ordination frameworks have the potential to open up previously unexplored directions for materials chemistry. This article focuses on the underlying concepts for the construction of these enticing and potentially highly important materials

[en] Structural changes occurring within non-conventional Dawson-type [α/β-Mo₁₈O₅₄(SO₃)₂]⁴⁻ polyanions in the form of tetrapentylammonium salts were studied by a combination of IR, Raman and visible spectroscopy at high temperature and high pressure. Evidence of the formation of bronze-type materials above 400 K and also upon pressurization to 8 GPa is presented. This conclusion is suggested to be a general result for polyoxometalate compounds subjected to extreme conditions and it opens opportunities for the design of new materials with interesting optical and electronic properties. - Graphical abstract: Structural changes occurring within non-conventional Dawson-type [α/β-Mo₁₈O₅₄(SO₃)₂]⁴⁻ polyanions in the form of tetrapentylammonium salts were studied by a combination of IR, Raman and visible spectroscopy at high temperature and high pressure. Evidence of the formation of bronze-type materials above 400 K and also upon pressurization to 8 GPa is presented. This conclusion is suggested to be a general result for polyoxometalate compounds subjected to extreme conditions and it opens opportunities for the design of new materials with interesting optical and electronic properties. Highlights: ► Spectroscopy studies of non-conventional Wells–Dawson polyoxometalates (POMs) at high temperature and high pressure. ► Discussion on the stability of two POM isomers. ► Local formation of bronze-like materials: possibilities for a new synthetic method at high pressure from POM precursors.