Reactions in solvothermal conditions between hexanuclear rare earth complexes and H2bdc, where H2bdc symbolizes terephthalic acid, lead to a family of monodimensional coordination polymers in which hexanuclear complexes act as metallic nodes. The hexanuclear cores can be either homometallic with general chemical formula [Ln6O(OH)8(NO3)6](2+) (Ln = Pr-Lu plus Y) or heterometallic with general chemical formula [Ln(6x)Ln'(6-6x)O(OH)8(NO3)6](2+) (Ln and Ln' = Pr-Lu plus Y). Whatever the hexanuclear entity is, the resulting coordination polymer is iso-structural to [Y6O(OH)8(NO3)2(bdc)(Hbdc)2·2NO3·H2bdc]∞, a coordination polymer that we have previously reported. The random distribution of the lanthanide ions over the six metallic sites of the hexanuclear entities is demonstrated by (89)Y solid state NMR, X-ray diffraction (XRD), and luminescent measurements. The luminescent and colorimetric properties of selected compounds that belong to this family have been studied. These studies demonstrate that some of these compounds exhibit very promising optical properties and that there are two ways of modulating the luminescent properties: (i) playing with the composition of the heterohexanuclear entities or (ii) playing with the relative ratio between two different hexanuclear entities. This enables the independent tuning of luminescence intensity and color.

Magnetic slow relaxation is observed in a Dy(III)-based molecular chain and the magnetic easy-axis is determined via single-crystal magnetometry. Ab initio calculations confirm its orientation and highlight that the latter is governed neither by coordination polyhedron symmetry nor by the chain direction but rather by the single-ion electrostatic environment, a feature that is confirmed by a similar theoretical analysis on other Dy(III) chains.

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For the first time, hexanuclear complexes with general chemical formula [Ln6O(OH)8(NO3)6(H2O)n](2+) with n = 12 for Ln = Sm-Lu and Y and n = 14 for Ln = Pr and Nd were stabilized as nanoaggregates in ethylene glycol (EG). These unprecedented nanoaggregates were structurally characterized by (89)Y and (1)H NMR spectroscopy, UV-vis absorption and luminescence spectroscopies, electrospray ionization mass spectrometry, diffusion ordered spectroscopy, transmission electron microscopy, and dynamic light scattering. These nanoaggregates present a 200 nm mean solvodynamic diameter. In these nanoaggregates, hexanuclear complexes are isolated and solvated by EG molecules. The replacement of ethylene glycol by 2-hydroxybenzyl alcohol provides new nanoaggregates that present an antenna effect toward lanthanide ions. This results in a significant enhancement of the luminescence properties of the aggregates and demonstrates the suitability of the strategy for obtaining highly tunable luminescent solutions.

A series of isostructural homo- and heterolanthanide coordination polymers of formula [Ln2(dcpa)3(H2O)]∞ with Ln = La–Gd have been obtained by reactions in water between the lightest lanthanide chlorides and the disodium salt of 4,5-dichlorophthalic acid (H2dcpa). They present particularly high thermal stability for coordination compounds (up to 400 °C). Their luminescent properties have been studied in detail. Interestingly an insensitivity to water coordination as well as a very strong effect of optical dilution is observed. Therefore, molecular alloys with very high lanthanum concentration have been prepared. Some of them present highly tunable and very intense luminescence. For example, to the best of our knowledge, [Sm0.04La1.96(dcpa)3(H2O)]∞ presents one of the highest overall quantum yields measured so far for a Sm3+-based coordination compound (Q Sm Ligand = 9.2%), and [Nd0.03Sm0.14Eu0.03La1.8(dcpa)3(H2O)]∞ is one of the brightest (12 Cd·m–2 under 0.75 mW·cm–2 UV flux) multiemissive visible and near-infrared lanthanide-coordination polymers reported to date.

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Highly luminescent and color-tunable stable colloidal suspensions of molecular alloys are reported. They are produced via a green synthetic route in ethanol medium. The mean hydrodynamic diameter of the colloids...

X-ray powder diffraction.Iso-structurality of the prepared molecular alloys, with [Eu 2 (dcpa) 3 (H 2 O)] ∞ 1 (F1) or with [Er 2 (dcpa) 3 (H 2 O) 5 •3H 2 O] ∞ (F2), 2 respectively, was assumed on the basis of their X-ray powder diffraction diagrams (Figures S1 to S5). Diagrams were collected using a Panalytical X'Pert Pro diffractometer equipped with an X'Celerator detector. Recording conditions were: 45 kV, 40 mA for Cu K ( = 1.542 Å) in / mode between 5° and 75°. Calculated patterns were produced using PowderCell and WinPLOTR programs. [3][4][5] Electron Dispersive Spectroscopy.Relative metallic contents of the different microcrystalline powders have been estimated on the basis of ESD measurements. Results of these measurements are listed in Tables S1 to S5. EDS measurements have been performed with a Hitachi TM-1000, Tabletop Microscope version 02.11 (Hitachi High-Technologies, Corporation Tokyo Japan) with EDS analysis system (SwiftED-TM, Oxford Instruments Link INCA). Samples were deposited on carbon discs. Reproducibility of the elemental analyses has been checked by repeating the measurements several times. These experiments confirm the homogeneity of the samples. Optical measurementsSolid-state emission and excitation spectra have been measured on a Horiba Jobin-Yvon Fluorolog III fluorescence spectrometer equipped with a Xe lamp 450 W, a UV-Vis photomultiplier (Hamamatsu R928, sensitivity 190-860 nm) and an IR-photodiode cooled by liquid nitrogen (InGaAs, sensitivity 800-1600 nm) or on a Horiba Jobin-Yvon FluoroMax 4 Plus fluorescence spectrometer equipped with a Xe lamp 150 W and a UV-Vis photomultiplier (Hamamatsu R928, sensitivity 190-860 nm). Quantum yield measurements were performed using a F-3018 Jobin-Yvon integrating sphere (  E c -E a )/(L a -L c ) with E c