Since the first description by Fievet, Lagier and Figlarz in 1989, the synthesis of nanoparticles in high-boiling, multivalent alcohols – so-called polyols – has been developed into a widely applied strategy, and nowadays belongs to the standard repertoire for preparing high-quality nanomaterials. The polyols take advantage of several features such as: (i) water-comparable solubility of simple metal-salt precursors; (ii) high boiling points (up to 320 °C); (iii) reducing properties for the instantaneous synthesis of metals; (iv) coordinating properties for surface functionalization and colloidal stabilisation of nanoparticles; (v) wide adaptability of the polyols ranging from low-weight ethylene glycol (EG) to high-weight polyethylene glycols (PEGs). This review summarises the status and perspectives on nanoscaled elemental metals, metal oxides, metal chalcogenides, and non-metal elements that were prepared via the polyol synthesis. Moreover, we summarize our results and concepts to expand the limits of the polyol synthesis. This includes strategies for less-noble metal synthesis, phase transfer reactions, photochemical reduction, NMR-based characterisation of polyol-functionalised nanoparticles, realisation of phase-pure and readily crystalline metal tungstates, stabilisation of low-melting elements, and controlled thermal decomposition of polyols to obtain high-quality, lanthanide-modified carbon dots (C-dots).

The series of anhydrous lanthanide chlorides LnCl₃, Ln = Pr–Tb, and 4,4′-bipyridine (bipy) constitute isotypic MOFs of the formula ² _∞[Ln₂Cl₆(bipy)₃]·2bipy. The europium and terbium containing compounds both exhibit luminescence of the referring trivalent lanthanide ions, giving a red luminescence for Eu³⁺ and a green luminescence for Tb³⁺ triggered by an efficient antenna effect of the 4,4′-bipyridine linkers. Mixing of different lanthanides in one MOF structure was undertaken to investigate the potential of this MOF system for colour tuning of the luminescence. Based on the gadolinium containing compound, co-doping with different amounts of europium and terbium proves successful and yields solid solutions of the formula ² _∞[Gd_2−x−yEu_xTb_yCl₆(bipy)₃]·2bipy (1–8), 0 ≤ x, y ≤ 0.5. The series of MOFs exhibits the opportunity of tuning the emission colour in-between green and red. Depending on the atomic ratio Gd:Eu:Tb, the yellow region was covered for the first time for an oxygen/carboxylate-free MOF system. In addition to a ligand to metal energy transfer (LMET) from the lowest ligand-centered triplet state of 4,4′-bipyridine, a metal to metal energy transfer (MMET) between 4f-levels from Tb³⁺ to Eu³⁺ is as well vital for the emission colour. However, no involvement of Gd³⁺ in energy transfers is observed rendering it a suitable host lattice ion and connectivity centre for diluting the other two rare earth ions in the solid state. The materials retain their luminescence during activation of the MOFs for microporosity.