Heteronuclear lanthanide terephthalate coordination polymers with the general chemical formula [Ln2–2xLn′2x(bdc)3(H2O)4]∞, for which bdc2– symbolizes benzene‐1,4‐dicarboxylate (or terephthalate) and Ln and Ln′ represent trivalent rare earth ions, were synthesized and structurally characterized. Analysis of the Y/Lu compounds by 89Y and 13C solid‐state NMR spectroscopy was carried out, and the results support the hypothesis of randomly distributed lanthanide ions. The spectroscopic and colorimetric properties of this family of compounds were investigated in detail. The resulting data demonstrate that this series of compounds presents highly tunable luminescence properties and clearly indicate that intermetallic deactivation processes play an important role in the emission mechanism. Playing with intermetallic distances allows one to tune the color and the brightness of the lanthanide emission in these coordination polymers.

Reactions in water between mixtures of rare earth ions (Ln =Y, La-Tm, except Pm) and the sodium salt of terephthalic acid lead to an infinite family of isostructural heteropolynuclear coordination polymers. The monophasic character of the synthesized powders as well as the isostructurality of the heteropolynuclear compounds with the previously described mononuclear [Tb(2)(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity) are ascertained on the basis of the X-ray powder diffraction diagrams. One family of heterodinuclear compounds has been studied in detail, that is, [(La(2-x)Y(x))(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity) with 0 < or = x < or = 2. This study demonstrates the random character of the spatial distribution of the metallic ions. In order to demonstrate the high modularity of the physical properties, the solid-state luminescent properties of the compounds of general formula [(Eu(2-x)Tb(x))(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity) with 0 < or = x < or = 2 have been studied and compared to those of the corresponding mixtures of [(Eu(2))(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity) and [(Tb(2))(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity). In order to confirm the general character of these studies, the compound containing in equal proportions all 13 rare earth ions between La and Tm (except Pm) plus Y has been synthesized and characterized. At last, the solid-state luminescent properties of compounds belonging to the ternary system [(Ce(2-x-y)Eu(x)Tb(y))(C(8)H(4)O(4))(3)(H(2)O)(4)](infinity) with x + y < or = 2 are briefly described.

International audienceThe near-IR luminescence properties of two ErIII-containing coordination polymers, namely, [Er(btc)(H2O)5·3.5H2O] [(btc)3– = 1,3,5-benzenetricarboxylate] and [Er2(bdc)3- (H2O)4] [(bdc)2– = 1,4-benzenedicarboxylate] were investigated with the aim of testing their potential use as optical materials. Because both present relatively small quantum yields and short excited-state lifetimes, factors influencing their luminescent properties were deciphered in an effort to improve their luminescent properties. Thus, three other families of compounds were also investigated: (i) the two corre-sponding dehydrated compounds with respective chemical formula [Er(btc)] and [Er2(bdc)3] for evaluating the importance of O–H vibrators, (ii) the heterodinuclear compounds [Er2–2xY2x(bdc)3(H2O)4] (x = 0.2, 0.5, 0.8 and 0.9) for estimating the role of intermetallic quenching and (iii) the heterodinuclear compounds [Er2–2xYb2x(bdc)3(H2O)4] (x = 0.2 and 0.5) for checking whether YbIII-sensitized up-conversion can be induced or not. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009