Molecular precursors for precision synthesis of nanomaterials

Welcome to this themed issue of Dalton Transactions focused on the utility of molecular precursors for the precision synthesis of nanomaterials. Nanomaterials are becoming increasingly important for applications ranging from optoelectronics, thermoelectrics and Li-ion batteries to catalysis, biochemistry and medicine. We have thus assembled a collection which covers the synthesis of (i) free standing colloidal nanostructures, as well as (ii) surface-supported molecularly defined species and nanoclusters. The common focus is on molecular precursors and their conversion into nanoscopic metals, semiconductors, metal oxides and hybrid materials including metal organic frameworks (MOFs); several contributions also address the question of characterizing them at the molecular level.

Very often organometallic or coordination compounds are employed by various research communities for very different purposes. As a typical example, both of our groups have been using metal and metalloid alkylamides and silylamide. In a perspective article (DOI: 10.1039/C3DT51346G), Liang and Anwander provide a comprehensive overview on the grafting of molecular metal amides to the surface of mesoporous and amorphous oxides (SiO₂, Al₂O₃etc.). Surface hydroxyl-groups displace the amido-ligand leading to stable grafting via a metal–oxygen bond, thus affording a distinct surface site. At the same time, a different research community is concentrated mainly on generating monodisperse colloidal semiconductors (quantum dots) and metals/metal oxides. For this purpose, metal amides are often used as highly-reactive, easily decomposable and oxygen-free precursors. To this end, a critical perspective is given by Chaudret et al. (DOI: 10.1039/c3dt50870f), focusing on the utility of organometallics and metal amides for the liquid phase, surfactant-assisted growth of colloidal nanoparticles. In particular, metal amides are shown to provide a good compromise in terms of reactivity at moderate temperatures, facile preparation and handling, often advantageous to extreme cases of unreactive inorganic metal salts on one side and highly unstable organometallics on the other side. Two other perspective articles focus on the synthesis of ZnO nanoparticles and phosphonates and a third one discusses the use of H₂ to probe surface divalent cations at the surface of MOFs.

Surface-supported metallic clusters/nanoparticles (Ru, Rh, Pt, Pd, Au, Ir–Sn etc.) and metal oxides (V₂O₅) are reported in dozens of research articles aimed at the development of novel efficient heterogeneous catalysts, designed for instance towards mild oxidation dehydrogenation processes. In addition, molecular precursors are also an important component for the preparation of well-defined so-called single-site catalysts and co-catalysts. Another collection of articles covers various aspects of the chemistry of colloidal nanocrystals and nanoparticles, including the catalytic growth of nanowires, controlled electronic doping and surface chemistry.

Finally, we would like to thank all authors who submitted their new research results as well as review articles to this special issue of Dalton Transactions and the editorial team of the journal for the fast and professional handling of the manuscripts.

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