Polymères de coordination à base de Terres Rares : porosité et propriétés optiques

L utilisation de lanthanides pour la synthèse de polymères de coordination ouvre de nombreuses perspectives car ceux-ci sont connus pour avoir des propriétés physiques intéressantes pour des domaines tel que la catalyse, le stockage de gaz, la luminescence. Nous avons développé une méthode de calcul de la porosité qui s appuie sur la structure cristallographique du composé et qui permet de s affranchir des différentes approximations expérimentales pour déterminer la porosité interne du composé. Nous nous sommes ensuite intéressés au système ions lanthanides-ligand téréphthalate et plus particulièrement à la famille de composés Ln2(TER)3(H2O)4. Nous avons synthétisé des nanoparticules de téréphthalate de lanthanide grâce à une technique d encapsulation par un polymère à longue chaîne puis nous avons travaillé sur un nouveau type de composé présentant au sein de la même structure cristallographique plusieurs lanthanides différents offrant au matériau des propriétés optiques modulables.We have developed a computational method that allows us to estimate the potential porosity of coordination polymers. This method, based only on crystallographic data, leads to a value which does not depend on sample geometry. It is particularly useful for studying coordination polymers with low thermal stability. It is also useful for comparing the potential porosity of materials with complex networks. We have been then interested in the development of lanthanide terephthalate compounds. All these compounds present only two type of crystallographic structure and one of them contains thirteen different lanthanides with the structure Ln2(TER)3(H2O)4. These compounds have been more particularly studied. We have synthesized nanoparticules using polymer encapsulation technique. Then we have worked on a new type of compounds which simultaneously contain several different lanthanides. The synergy between the different lanthanides ions leads to new compounds exhibiting original properties.RENNES-INSA (352382210) / SudocSudocFranceF

A new family of luminescent lanthanide based coordination polymers.

WOSInternational audienceReaction inwater between a lanthanide ion (Ln = Sm–Dy) and the sodium salt of isophthalic acid leads to a newfamily of lanthanide-based coordination polymers. The crystal structure has been solved on the basis of the Gd containing compound. The iso-structurality of the other compounds has been assumed on the basis of powder X-ray diffraction diagrams. These compounds of general formula Ln2(OH)(C8H4O4)2(C8H5O4)(H2O)8·6H2O crystallize in the monoclinic system, space group P21/a (no. 14) with a = 17.4249(2) A° , b = 10.9148(1) A° , c = 20.7216(2) A° , β = 113.1694(4)◦ and Z = 4. This crystal structure is 1-D. Chains are bound to each other by hydrogen bonds. The thermal stability of these compounds is described and discussed as well as luminescent properties of the coordination polymers involving luminescent rare earth ions

A new 3-D La(lll)-Cu(ll) Containing Coordination Polymer with High Potential Porosity.

WOSInternational audienceA new 3-D coordination polymer containing both 3d and 4f ions has been designed. Its chemical formula is La2[Cu(pba)]3(H2O)8•8H2O. It crystallizes in the quadratic system, space group I41/a with a = 42.4947(9) Å, c = 16.3378(3) Å, and Z = 16. Its crystal structure can be described as a 3-D molecular framework exhibiting a complex network of interconnected zigzaglike channels. Once crystallization water molecules are removed, this compound presents a high potential porosity and a low density. The porosity has been evaluated using Connolly's algorithm

The First two Lanthanum-Containing Coordination Polymers Involving Naphtalene-1,4,5,8-tetra-carboxylate as Ligand.

International audienceReaction in an aqueous gel medium between a lanthanide ion and the sodium salt of the naphthalene- 1,4,5,8-tetra-carboxylic acid can lead to coordination polymers. We report here the synthesis, the crystal structure, the thermal analysis and the calculated porosity of two new coordination polymers involving the lanthanum ion. The thermal properties of compound [LaNa[(C10H4)(COO)4](H2O)7 4H2O]1 have also been studied and are reported here

A New Family of Porous Lanthanide-Containing Coordination Polymers : [ Ln2 (C2O4)3(H2O)6,12H2O] with Ln = La - Yb or Y

International audienceReactions at low temperature in a mixture benzene/water between dimethyloxalate and a lanthanide chloride lead to a family of 3D-coordination polymers with general chemical formula [Ln2(C2O4)3(H2O)6 3 12H2O]¥, where Ln=La-Yb (except Pm) or Y. All these compounds are isostructural to the already described [Er2(C2O4)3(H2O)6 3 12H2O]¥. Their crystal structure can be described as the juxtaposition of channels with hexagonal cross-section. The channels are filled with crystallization water molecules. Their thermal dehydration produces a collapse of the molecular skeleton leading to amorphous compounds.On the opposite, their dehydration by freeze-drying is possible and the twelve crystallization water molecules can be removed without destruction of the molecular skeleton. The porosity of the dehydrated compounds has been estimated by computational methods to 483 m2 g-1. The luminescence properties of the Eu-containing and Tb-containing compounds are also briefly described

New lanthanide based coordination polymers with high potential porosity.

International audienceReaction in an aqueous gel medium between a lanthanide ion and the sodium salt of the naphthalene-tetra-carboxylic acid can lead to coordination polymers. We report here the synthesis, the crystal structure and the calculated porosity of the first two new coordination polymers, namely Gd[(C10H4)(COO)3(COOH)](H2O)4·9H2O and Er4[(C10H4)(COO)4]3(H2O)10·12H2O. The first compound crystallizes in the triclinic system, space group P¯1 (no. 2) with a = 6.4456(1) A° , b = 12.0131(3) A° , c = 16.4256(4) A° , α = 107.8706(9)◦, β = 97.0735(9)◦, γ = 93.4771(15)◦ and Z=2. The crystal structure can be described as wavy planes strongly connected to each other by hydrogen bonds. This pseudo 3D crystal structure presents very large rectangular channels filled by crystallization water molecules. The second compound crystallizes in the monoclinic system, space group P21/c (no. 14) with a = 9.8442(1) A° , b = 29.2288(2) A° , c = 10.8795(1) A° , β = 92.1767(3)◦ and Z = 4. Its crystal structure is 3D and presents some large channels with rectangular sections. These channels are full of crystallization water molecules. In both cases, the crystallization water molecules have been formally removed and the porosity has been calculated using Connolly's algorithm. Both present a rather high potential porosity

An Unprecedented Family of Lanthanide-Containing Coordination Polymers with Highly Tunable Emission Properties.

International audienceReactions 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 [Tb2(C8H4O4)3(H2O)4]∞ are ascertained on the basis of the X-ray powder diffraction diagrams. One family of heterodinuclear compounds has been studied in detail, that is, [(La2-xYx)(C8H4O4)3(H2O)4]∞ with 0 e x e 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 [(Eu2-xTbx)(C8H4O4)3(H2O)4]∞ with 0 e x e 2 have been studied and compared to those of the corresponding mixtures of [(Eu2)(C8H4O4)3(H2O)4]∞ and [(Tb2)(C8H4O4)3(H2O)4]∞. 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 [(Ce2-x-yEuxTby)(C8H4O4)3(H2O)4]∞ with x + y e 2 are briefly described

Malonate-containing Manganese(III) Complexes : Synthesis, Crystal Structure and Magnetic Properties of AsPh4[Mn(mal)2(H2O)2]

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Malonate Containing Manganese lll Complexes : Synthesis, Crystal structure and Magnetic Properties of AsPh4[Mn(mal)2(H20)2]

WOSInternational audienceThe novel manganese(III) complexes PPh4[Mn(mal)2(H2O)2] (1) and AsPh4[Mn(mal)2(H2O)2] (2) (PPh4+ )tetraphenylphosphonium cation, AsPh4+ ) tetraphenylarsonium cation, and H2mal ) malonic acid) have been prepared, and the structure of 2 was determined by X-ray diffraction analysis. 2 is a mononuclear complex whose structure is made up of trans-diaquabis(malonato)manganate(III) units and tetraphenylarsonium cations. Two crystallographically independent manganese(III) ions (Mn(1) and Mn(2)) occur in 2 that exhibit elongated octahedral surroundings with four oxygen atoms from two bidentate malonate groups in equatorial positions (Mn(1)-O )1.923(6) and 1.9328(6) Å and Mn(2)-O ) 1.894(6) and 1.925(6) Å) and two trans-coordinated water molecules inthe axial sites (Mn(1)-Ow ) 2.245(6) Å and Mn(2)-Ow ) 2.268(6) Å). The [Mn(mal)2(H2O)2]- units are linked through hydrogen bonds involving the free malonate-oxygen atoms and the coordinated water molecules to yielda quasi-square-type anionic layer growing in the ab plane. The shortest intralayer metal-metal separations are 7.1557(7) and 7.1526(7) Å (through the edges of the square). The anionic sheets are separated from each other by layers of AsPh4+ where sextuple- and double-phenyl embraces occur. The magnetic behavior of 1 and 2 in thetemperature range 1.9-290 K reveals the occurrence of weak intralayer ferromagnetic interactions (J = +0.081(1)(1) and +0.072(2) cm-1 (2)). These values are compared to those of the weak antiferromagnetic coupling [J = -0.19(1) cm-1], which is observed in the chain compound K2[Mn(mal)2(MeOH)2][Mn(mal)2] (3), where the exchange pathway involves the carboxyate-malonate bridge in the anti-syn conformation. The structure of 3 was reported elsewhere. Theoretical calculations on fragment models of 2 and 3 were performed to analyze and substantiate both the nature and magnitude of the magnetic couplings observed

Synthesis, Crystal Structure and Porosity Estimation of Hydrated Erbium Terephthalate Coordination Polymers.

WOSInternational audienceThe reaction of Er3+ ion with poly-carboxylate ligands in gel media leads to coordination polymers exhibiting various structural types and various dimensionality. Five Er3+ / 1,4-benzenedicarboxylate based coordination polymers have been obtained in such conditions. Four out of five are new. Their crystal structures are reported and compared herein. The compound (1-), namely Er2Ter3(H2O)6, where H2Ter symbolizes the terephtalic acid, crystallizes in the space group (N°2) with a=7.8373(10)Å, b=9.5854(2)Å, c=10.6931(2)Å, a=68.7770(8)°, b=70.8710(8)°, g=75.3330(12)°. It has already been reported elsewhere. The last four compounds are new. The compound (2-), namely Er2Ter3(H2O)6,2H2O crystallizes in the space group (N°14) with a=6.7429(2)Å, b=22.4913(7)Å, c=9.6575(3)Å, b=91.6400(18)°. The compound (3-), namely Er2Ter3(H2O)8,2H2O crystallizes in the space group (N°2) with a=7.5391(2)Å, b=10.0533(3)Å, c=10.4578(3)Å, a=87.7870(10)°, b=82.5510(11)°, g=86.2800(16)°. The compound (4-), namely Er2Ter3(H2O)6,2H2O crystallizes in the space group (N°15) with a=38.5123(13)Å, b=11.1241(4)Å, c=7.0122(2)Å, b=98.634(2)°. The compound (5-), namely Er2Ter3(H2O)6,H2O crystallizes in the space group (N°2) with a=6.8776(10)Å, b=11.0420(2)Å, c=18.5675(3)Å, a=84.7240(6)°, b=81.8380(6)°, g=84.1770(8)°. A computational method has also been developed in order to evaluate the potential porosity of coordination polymers. This method is described then applied to the different Er2Ter3(H2O)n coordination polymers previously described