Novel stable ytterbium acetylacetonate-quinaldinate complexes as single-molecule magnets and surprisingly efficient luminophores.

The first Yb complexes comprising a quinoline-2-carboxylate (quinaldinate, Q) ligand, namely 1D-polymeric [Yb(acac)(Q)] (1, acac is the acetylacetonate (pentane-2,4-dionate) anion) and mononuclear [Yb(acac)(Q)(Phen)] (2, Phen is 1,10-phenanthroline), are reported. The bifunctionality of both complexes as field-induced single-molecule magnets (SMMs) and near IR luminophores has been revealed. The SMM properties of 1 and 2 have been discussed in terms of the geometry and composition of the coordination environment.

Supercritical fluid-assisted modification combined with the resynthesis of SmCoO as an effective tool to enhance the long-term performance of SmCoO-derived catalysts for the dry reforming of methane to syngas.

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO-based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO-derived catalysts combined with the re-oxidation of spent catalysts to SmCoO onto its long-term performance was studied.

Mononuclear Transition Metal Cymantrenecarboxylates as Precursors for Spinel-Type Manganites.

Novel mononuclear cymantrenecarboxylate complexes of transition metals, [Co(HO)](CymCO)·4HO (Cym = (η-CH)Mn(CO)) (), [Ni(HO)](CymCO)·4HO (), [Zn(HO)](CymCO)·4HO (), [Co(CymCO)(imz)] (imz = imidazole, ), [Co(CymCO)(bpy)]·2PhMe (bpy = 2,2'-bipyridyl, ), [Ni(CymCO)(bpy)(HO)][CymCO]·0.5MePh·2HO (), [Cu(CymCO)(imz)] (), and [Cu(CymCO)(bpy)(HO)] (), were obtained and characterized by single-crystal X-ray analysis. Complexes - are isostructural.

Tetranuclear Cr-Ln ferrocenecarboxylate complexes with a defect-dicubane structure: synthesis, magnetism, and thermolysis.

Using ferrocenecarboxylic acid (FcCOH) and triethanolamine (Htea) as ligands, the isostructural heterotrimetallic complexes [LnIII2CrIII2(OH)(FcCO)(NO)(Htea)]·2MePh·2THF (Ln = Tb (1), Dy (2), Ho (3), Er (4), and Y (5); Fc = (η-CH)(η-CH)Fe; Htea = N(CHCHOH)) were obtained. In all of the complexes which possess a defective dicubane structure, two doubly deprotonated triethanolamine ligands chelate the chromium ions. However, during the synthesis of 1, an isomeric complex 1a in which Tb is chelated by triethanolamine as a tetradentate ligand, was also isolated as a few single crystals.

Identification of Barium Hydroxo-Hydroperoxostannate Precursor for Low-Temperature Formation of Perovskite Barium Stannate.

A breakthrough "superoxide colloidal solution route" for low-temperature synthesis of barium and strontium stannate perovskites and their doped analogues was recently introduced. The synthesis starts from hydrogen peroxide-rich stannate solutions and yields a so-called "crystalline superoxide molecular cluster" that is converted by low temperature (<300 °C) to the respective perovskites. In this paper, the so-called "crystalline superoxide molecular cluster" is identified as a superoxide-free, barium trihydroxo(hydroperoxo)peroxostannate, BaSn(OH)(OOH)(OO) phase (BHHPS).

The crystal structure of new quantum memory-storage material ScYSiO.

Monoisotopic scandium yttrium oxyorthosilicate crystals as a material for quantum memory storage with high optical quality were grown by the Czochralski method. This material, of composition ScYSiO, is characterized by congruent melting and a melting point 60 K below the temperature for the ideal solid-solution series YSiO-ScSiO. The structure of the crystals was refined on the basis of high-quality single-crystal X-ray diffraction data.

Towards comparative investigation of Er- and Yb-based SMMs: the effect of the coordination environment configuration on the magnetic relaxation in the series of heteroleptic thiocyanate complexes.

We prepared and studied two similar series of Er and Yb thiocyanates, involving [Ln(HO)(NCS)]·HO (1Er, 1Yb) as well as the molecular and ionic complexes with 2,2'-bipyridine (bpy) and 1,10-phenantroline (phen), [Ln(HO)(bpy)(NCS)]·0.5(bpy)·HO (2Er, 2Yb), [Ln(HO)(phen)(NCS)]·phen·0.5HO (3Er, 3Yb), [Hbpy][Ln(bpy)(NCS)]·HO (4Er, 4Yb) and [Hphen][Ln(phen)(NCS)] (5Er, 5Yb).

Unexpected hydrolytic transformation of new type hybrid bromobismuthates with methylpyrazinium dications.

A series of new type hybrid bromobismuthates formed by various pyrazinium cations were isolated and studied. In the systems initially containing iodide anions and monocations of substituted pyrazines, the complexes based on doubly charged cations of substituted pyrazines instead of ones based on the corresponding monocations were surprisingly formed. The variation of substituted pyrazinium cations affects not only the crystal structures of hybrid bromobismuthates via tuning the nuclearity of the anions but also the hydrolytic stability of the compounds.

Yb can be much better than Dy: SMM properties and controllable self-assembly of novel lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes.

The first representatives of the binuclear lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes, namely isostructural compounds [Ln(dnbz)(acac)2(H2O)(EtOH)]2 (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), and Yb (8); dnbz - 3,5-dinitrobenzoate anion; acac - acetylacetonate (pentane-2,4-dionate) anion) were prepared and characterized. The SMM behavior of the Yb compound 8 was shown to be surprisingly less sensitive to the composition of the Yb3+ coordination environment in comparison with that of the Dy derivative. For Yb compound 8, the anisotropy barrier is Δeff/kB = 26 K under the dc field of 2000 Oe.

Novel mononuclear Ln complexes with pyrazine-2-carboxylate and acetylacetonate co-ligands: remarkable single molecule magnet behavior of a Yb derivative.

A series of novel isomorphic mononuclear complexes [Ln(PyrCOO)(acac)(HO)] (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), Yb (8), Y(9); acac - acetylacetonate (pentane-2,4-dionate) anion, PyrCOOH is pyrazine-2-carboxylic acid) were prepared. Slow magnetic relaxation indicating SMM behavior was found in complexes 3, 4, 6 and 8. For 4 (Dy), the anisotropy barrier is Δ/k = 77 K under a dc field of 1500 Oe.

Novel mononuclear and 1D-polymeric derivatives of lanthanides and (η-benzoic acid)tricarbonylchromium: synthesis, structure and magnetism.

Two series of novel heteroleptic derivatives of lanthanides and (η-benzoic acid)tricarbonylchromium (benchrotrenecarboxylic acid) were synthesized and characterized: mononuclear complexes [Ln(BcrCOO)(acac)(HO)] (Ln = Eu (1), Gd (2), Tb (3a), Dy (4a), Ho (5a)) and 1D-polymeric ones [Ln(BcrCOO)(acac)(HO)] (Ln = Tb (3b), Dy (4b), Ho (5b), Er (6), Tm (7), Yb (8) and Y (9)), Bcr = (η-CH)Cr(CO). The molecular and crystal structures of the obtained compounds were determined. Complexes 3a, 4a, 4b, 6 and 8 were found to exhibit SMM properties.

Synthesis, structure, and physical properties of new rare earth ferrocenoylacetonates.

New ferrocenoylacetonate complexes of several rare earth elements, [Ln(fca)3(bpy)]·MeC6H5 (Ln = Pr (), Eu (), Gd (), Tb (), Dy (), Ho (), Y (); bpy - 2,2'-bipyridine; Hfca - FcCOCH2COMe) as well as scandium ferrocenoylacetonate [Sc(fca)3]·0.5MeC6H5 (), were synthesized and characterized by single crystal X-ray diffraction analysis. In the crystal lattice of the isostructural complexes , two [Ln(fca)3(bpy)] molecules form a pair due to stacking interactions between the bpy ligands.

Heterodinuclear (Sm, Tb) lanthanide pivalates with heterocyclic N-donors: synthesis, structure, thermal behavior, and magnetic and photoluminescence properties.

Heterobimetallic complexes [SmTb(piv)6(phen)2] (1), [SmTb(piv)6(bath)2]·1.75EtOH (2a·1.75EtOH), [SmTb(piv)6(bath)2]·2EtOH (2b·2EtOH), and [SmTb(piv)6(bath)2]·EtOH (2b·EtOH), where piv is (CH3)3CCO2(-), phen is 1,10-phenanthroline, and bath is 4,7-diphenyl-1,10-phenanthroline, were synthesized and studied by X-ray diffraction.