Lord of The Crowns: A New Precious in the Kingdom of Clustomesogens

Abstract

Replacing pure inorganic materials by functional organic-inorganic hybrid ones to lower production costs has become a major challenge, in particular for the optoelectronic industry. Adding nanostructuration abilities meanwhile preserving homogeneity is even more challenging for this class of new materials. Here we show that red-NIR emissive ternary molybdenum cluster salts can be assembled to liquid crystalline 15C5 crown ethers. The resulting hybrids are homogeneous and stable up to high temperature despite the weakness of the supramolecular interactions binding both components. These are illustrated by Cs MAS NMR. All hybrids show hexagonal columnar arrangements and strong red-NIR emission. Surprisingly, when chlorinated clusters are used instead of brominated ones, the mesophase stability is largely enhanced.

From supramolecular to solid state chemistry: crystal engineering of luminescent materials by trapping molecular clusters in an aluminium-based host matrix

“…Then, the self-assembling of building blocks to form the target material will be driven by a supramolecular organic linker, such as cyclodextrins as demonstrated earlier in CLUSPOM compounds. 9 the elaboration of hybrid nano-materials [30][31][32][33][34][35] and functional surfaces 36,37 . In particular, they i) absorb light continuously from UV to visible, ii) emit continuously from red to NIR region through several excited emissive states, iii) are able to photoinduce singlet oxygen generation, iv) exhibit interesting catalytic and photo-catalytic properties.…”

Original Synthesis of Molybdenum Nitrides Using Metal Cluster Compounds as Precursors: Applications in Heterogeneous Catalysis

“…• RESULTS AND DISCUSSION Choice of the precursor As defined by Cotton et al 35 cluster compounds are aggregates of finite dimensions of metal atoms connected to each other by metal-metal bonding. Transition metal cluster compounds are widely used for their luminescence or UV-NIR absorption properties [36][37][38][39][40] . In this work, the true nanoscale aspect (≈1 nm) of these compounds is used in order to form nanostructured molybdenum nitrides.…”

Designing Functional Polyoxometalate‐Based Ionic Liquid Crystals and Ionic Liquids

“…In addition to the two previous approaches, Molard and coworkers developed another strategy with hexametallic clusters which consisted in trapping the alkali counter cations, especially K + and Cs + , within functionalized 15C5 or 18C6 crown ethers (see Figure 10). [91,92] Following this idea, they succeeded to design columnar hexagonal arrangements mainly due to discotic-like complex formed between the crown ethers and the alkali, while the metallic clusters, well known for their strong luminescence properties, were localized between the columns (see Figure 11). Even if this family of clusters does not formally belong to POM's family, this strategy constitutes a very interesting perspective for developing new POM-based ionic liquid crystals with new arrangements.…”

“…Figure 10. Representation of 15C5 and 18C6 crown ethers derivatives used by Molard and coworkers to coordinate K + and Cs + counter cations paired with hexametallic clusters [Mo 6 X 14 ] 2-(X = Cl, Br, I) and [Mo 6 I 8 (C 2 F 5 COO) 6 ] 2- [91,92]. …”