9-Cobalt(II)-Containing 27-Tungsto-3-germanate(IV): Synthesis, Structure, Computational Modeling, and Heterogeneous Water Oxidation Catalysis.

The 9-cobalt(II)-containing trimeric, cyclic polyanion [Co(OH)(HO)(PO)(GeWO)] () was synthesized in an aqueous phosphate solution at pH 8 and isolated as a hydrated mixed sodium-cesium salt. Polyanion was structurally and compositionally characterized in the solid state by single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, as well as thermogravimetric and elemental analyses. The magnetic and electrochemical properties of were also studied and compared with those of its phosphorus analogue, [Co(OH)(HO)(HPO)(PWO)] ().

Conducting Anilate-Based Mixed-Valence Fe(II)Fe(III) Coordination Polymer: Small-Polaron Hopping Model for Oxalate-Type Fe(II)Fe(III) 2D Networks.

The mixed-valence FeFe 2D coordination polymer formulated as [TAG][FeFe(ClCNAn)]·(solvate) 1 (TAG = tris(amino)-guanidinium, ClCNAn = chlorocyanoanilate dianionic ligand) crystallized in the polar trigonal space group P3. In the solid-state structure, determined both at 150 and at 10 K, anionic 2D honeycomb layers [FeFe(ClCNAn)] establish in the ab plane, with an intralayer metal-metal distance of 7.860 Å, alternating with cationic layers of TAG.

Tuning the spin crossover behavior of the polyanion [(HO)Fe(μ-L)]: the case of the cesium salt.

The magnetic behavior of the polyanion [Fe3(μ-L)6(H2O)6]6- (L2- = (1,2,4-triazol-4-yl)ethanedisulfonate) as the corresponding dimethylammonium salt shows memory effect above room temperature, with a dynamic thermal hysteresis cycle over 90 K and temperature-induced excited spin state trapping (TIESST) phenomena at the highest temperatures reported. Taking advantage of the polyanionic nature of this trimetallic complex, we were able to substitute the dimethylammonium cations by the monovalent heavy alkali metal cesium. This methathesis yielded the salt Cs6[Fe3(μ-L)6(H2O)6], with different molecular packing that increases the number and strength of cation-anion interactions, including a more robust H-bonded network.

A robust and unique iron(ii) mosaic-like MOF.

A novel extended triazole-based ligand (PM-Tria) has been synthesized and an unprecedented MOF 3D has serendipitously been formed by assembling iron(ii), PM-Tria ligand and fluoride anions. This MOF contains a perfectly linear one-dimensional {Fe(ii)-F}n bridging chain that shows an antiferromagnetic behaviour. Furthermore, the structure is compared with a 14th century mosaic found in the Alhambra Palace in Granada showing a surprising symmetry resemblance.

Ln12 -Containing 60-Tungstogermanates: Synthesis, Structure, Luminescence, and Magnetic Studies.

A new class of hexameric Ln12 -containing 60-tungstogermanates, [Na(H2 O)6 ⊂Eu12 (OH)12 (H2 O)18 Ge2 (GeW10 O38 )6 ](39-) (Eu12 ), [Na(H2 O)6 ⊂Gd12 (OH)6 (H2 O)24 Ge(GeW10 O38 )6 ](37-) (Gd12 ), and [(H2 O)6 ⊂Dy12 (H2 O)24 (GeW10 O38 )6 ](36-) (Dy12 ), comprising six di-Ln-embedded {β(4,11)-GeW10 } subunits was prepared by reaction of [α-GeW9 O34 ](10-) with Ln(III) ions in weakly acidic (pH 5) aqueous medium. Depending on the size of the Ln(III) ion, the assemblies feature selective capture of two (for Eu12 ), one (for Gd12 ), or zero (for Dy12 ) extra Ge(IV) ions. The selective encapsulation of a cationic sodium hexaaqua complex [Na(H2 O)6 ](+) was observed for Eu12 and Gd12 , whereas Dy12 incorporates a neutral, distorted-octahedral (H2 O)6 cluster.

Easy Excited-State Trapping and Record High TTIESST in a Spin-Crossover Polyanionic Fe(II) Trimer.

Reaction of the polysulfonated triazole ligand L = 4-(1,2,4-triazol-4-yl)ethanedisulfonate) with iron(II) salts in water yields the trimeric species [Fe3(μ-L)6(H2O)6](6-). This polyanion, as the dimethylammonium salt, shows a thermally induced spin transition above room temperature for the central Fe position in the trimer with a large hysteresis cycle (>85 K) and remarkably slow dynamics. This allows easy quenching of the metastable high-spin (HS) state via gradual cooling (5 K min(-1)).

Single-molecule-magnet behavior in the family of [Ln(OETAP)2] double-decker complexes (Ln=lanthanide, OETAP=octa(ethyl)tetraazaporphyrin).

Double-decker complexes of lanthanide cations can be readily prepared with tetraazaporphyrins (porphyrazines). We have synthesized and characterized a series of neutral double-decker complexes [Ln(OETAP)2 ] (Ln=Tb(3+), Dy(3+), Gd(3+), Y(3+); OETAP=octa(ethyl)tetraazaporphyrin). Some of these complexes show analogous magnetic features to their phthalocyanine (Pc) counterparts.