60 research outputs found
Synthesis and characterization of a new Organic - Inorganic sulfate (C5H6N2O)2[Co(H2O)6]3(SO4)4.2H2O
crystals of a new hybrid compound, (C5H6N2O)2[Co(H2O)6]3(SO4)4.2H2O, were synthesized in aqueous solution and characterized. This compound crystallizes in the triclinic system with the space group P-1, the unit cell :a=6.632(3) Å, b=11.769(5) Å, c=14.210(6) Å, α=67.86(4)°, β=81.32(4)°, γ=85.18(4)° and V=1015.14(8) Å3 . Its crystal structure can be described as a packing of alternated inorganic and organic layers. The different components are connected by a three-dimensional network of O-H...O and N-H...O hydrogen bonds
Azido and thiocyanato bridged dinuclear Ni(II) complexes involving 8-aminoquinoline based Schiff base as blocking ligands: crystal structures, ferromagnetic properties and magneto-structural correlations
The use of two 8-aminoquinoline-based tridentate N3-donor rigid Schiff base ligands (L1 and L2) with Ni(II) in the presence of the pseudohalides, NaN3 and NaSCN results in the crystallization of the two novel Ni(II) dimers: [Ni2(L1)2(µ1,1′-N3)2(N3)2] (1) and [Ni2(L2)2(µ1,3-NCS)2(NCS)2] (2). Both complexes are centrosymmetric Ni(II) dimers where the Schiff base ligands coordinate the octahedral Ni(II) centres in a mer configuration with one terminal and two bridging pseudohalide ligands in the remaining positions. Complex 1 shows Ni(II) ions connected by a double µ1,1′-N3− bridge whereas in complex 2 the Ni(II) ions are connected by a double µ1,3-NCS− bridge. The magnetic properties show the presence of a weak ferromagnetic coupling in both compounds that can be fit with g = 2.290(6), J = 6.1(2) cm−1, zJ′ = −0.32(1) cm−1 and |D| = 4.34(5) cm−1 for 1 and g = 2.096(2), J = 4.71(5) cm−1, zJ′ = −0.054(2) cm−1 and |D| = 1.52(2) cm−1 for 2 (the Hamiltonian is written as −2JS1S2). Both J values have been rationalized in terms of previous magneto structural correlations based on the Ni-N-Ni bridging angle in 1 and on the asymmetry of the Ni-S-C-N-Ni bridges in 2.publishe
Solvent-tuned ultrasonic synthesis of 2D coordination polymer nanostructures and flakes
Altres ajuts: the ICN2 is funded by the CERCA programme / Generalitat de Catalunya. Noemà Contreras Pereda's project that gave rise to these results received the support of a fellowship from "laCaixa" Foundation (ID 100010434). The fellowship code is LCF/BQ/ES17/11600012.Herein, a new 2-dimensional coordination polymer based on copper (II), {Cu₂(L)(DMF₂)}n, where L stands for 1,2,4,5-benzenetetracarboxylate (complex 1) is synthesized. Interestingly, we demonstrate that both solvent and sonication are relevant in the top-down fabrication of nanostructures. Water molecules are intercalated in suspended crystals of complex 1 modifying not only the coordination sphere of Cu(II) ions but also the final chemical formula and crystalline structure obtaining {[Cu(L)(H₂O)₃]·H₂O}n (complex 2). On the other hand, ultrasound is required to induce the nanostructuration. Remarkably, different morphologies are obtained using different solvents and interconversion from one morphology to another seems to occur upon solvent exchange. Both complexes 1 and 2, as well as the corresponding nanostructures, have been fully characterized by different means such as infrared spectroscopy, x-ray diffraction and microscopy
The Complete Series of Lanthanoid-Chloranilato Lattices with Dimethylsulfoxide: Role of the Lanthanoid Size on the Coordination Number and Crystal Structure
We report the synthesis, structural and magnetic characterization of the complete series of lanthanoid-based chloranilato 2D lattices with dimethylsulfoxide (dmso) formulated as: [Ln2(C6O4Cl2)3(dmso)6] with Ln = La(1), Ce(2), Pr(3), Nd(4), Sm(5), Eu(6), Gd(7) and Tb(8) or [Ln2(C6O4Cl2)3(dmso)4]·2dmso·2H2O with Ln = Dy(9), Ho(10), Er(11), Tm(12) and Yb(13); C6O4Cl22− = dianion of 3,6-dichloro-2,5-dihydroxy-1,4-benzoquinone = chloranilato. Single crystal X-ray analysis shows that the largest Ln(III) ions (La–Tb, 1–8) crystallise in the monoclinic P21/n space group (phase I), whereas the smallest ones (Dy–Yb, 9–13) crystallise in the triclinic P-1 space group (phase II). Both phases show a (6,3)-2D network with the typical hexagonal honeycomb lattice, although phase I presents important distortions, resulting in rectangular cavities with a brick-wall orientation. The largest ions (phase I) show a coordination number of nine with a capped square antiprismatic geometry in contrast to the smallest ions (phase II) that present a coordination number of eight with a triangular dodecahedral geometry. Magnetic measurements show that all the Ln(III) ions are magnetically well isolated, leading to the presence of a field induced single-ion magnet behaviour in the Er derivative, with an energy barrier of 23(2) K for DC fields of 20, 50 and 100 mT
A Family of Lanthanoid Dimers with Nitroanilato Bridges
The first complexes with lanthanoid ions and the nitroanilato ligand have been synthesized (nitroanilate dianion = [C6O4(NO2)2]2− = dianion of the 3,6-dinitro-2,5-dihydroxo-1,4-dibenzoquinone ligand). This family of dimers can be formulated as [Ln2(C6O4(NO2)2)3(H2O)10]·6H2O with Ln(III) = Sm (1), Gd (2), Tb (3), Dy (4), Ho (5), and Er (6). The X-ray structure of this family of isostructural complexes shows that they all present a dimeric structure where the Ln3+ ions are connected by a bis-bidentate nitroanilato ligand. Each metal completes its nonacoordination environment with a terminal bidentate nitroanilato ligand and five water molecules in a slightly distorted tri-capped trigonal prismatic geometry. The magnetic properties of this family show the expected contributions of the lanthanoid ions without any noticeable magnetic interaction through the nitroanilato ligand. The compounds present luminesce of the nitroanilato ligand superimposed with a weaker emission from the lanthanide ion in compound 5 (Ho)
Polymorphism and Metallic Behavior in BEDT-TTF Radical Salts with Polycyano Anions
Up to five different crystalline radical salts have been prepared with the organic donor BEDT-TTF and three different polynitrile anions. With the polynitrile dianion tcpd2− (=C[C(CN)2]32−), two closely related radical salts: α\u27-(ET)4tcpd·THF (1) (THF = tetrahydrofurane) and α\u27-(ET)4tcpd·H2O (2) have been prepared, depending on the solvent used in the synthesis. With the mono-anion tcnoetOH− (=[(NC)2CC(OCH2CH2OH)C(CN)2]−) two polymorphs with similar physical properties but different crystal packings have been synthesized: θ-(ET)2(tcnoetOH) (3) and β\u27\u27-(ET)2(tcnoetOH) (4). Finally, with the mono-anion tcnoprOH− (=[(NC)2CC(OCH2CH2CH2OH)C(CN)2]−) we have prepared a metallic radical salt: β\u27\u27-(ET)2(tcnoprOH)(CH2Cl2CH3Cl)0.5 (5). Salts 1‑4 are semiconductors with high room temperature conductivities and activation energies in the range 0.1–0.5 eV, whereas salt 5 is metallic down to 0.4 K although it does not show any superconducting transition above this temperature
Conception de nouveaux matériaux magnétiques et de conducteurs à base de ligands polynitrile fonctionnalisés
Les anions polynitrile représentent de très bons ligands dans la conception de matériaux moléculaires magnétiques à structures variées. Dans ce contexte, nous avons étudié la réactivité de trois anions polynitrile originaux (dcnoetOH), (tcnoetOH) et (tcnoprOH) avec des métaux de transition aboutissant ainsi à de nouvelles phases cristallines magnétiques. Dans le but de soupeser l influence d un co-ligand neutre, nous avons songé à l association du co-ligand 4,4 -bipyridine générant ainsi un éventail d architectures moléculaires. L introduction du ligand chélate abpt (4-amino-3,5-bis(pyridin-2- yl)-1 ,2,4-triazole) a complété la série de complexes à transition de spin [Fe(abpt)2(L) 2]. Pour finir, nous avons combiné certains de ces anions polynitrile originaux avec un donneur organique : le bis(éthylènedithio)tétrathiafulvalène (ET ou BEDT-TTF) par électrocristallisation et nous avons obtenu des sels semiconducteurs de phases distinctes telles que a , et b .The polynitrile anions are very interesting hi the field of molecular and magnetic materials. In this context, we have studied the reactivity of three new polynitrile ligands (dcnoetOH), (tcnoetOH) and (tcnoprOH) with transition metal ions which has led to new magnetic compounds. In order to evaluate the influence of a neutral co-ligand, we have introduced the 4,4 -bipyridine in the Metal-Polynitrile binary system. This combination displayed a rich and original range of molecular architectures. The use of an additional chelate ligand abpt (4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) has completed a series of spin crossover complexes of [Fe(abpt) 2 (L) 2] system. Finally, we have combined some of these polynitrile anions with the organic donor bis(ethylenedithio)tetrathiafulvalene (ET or BEDT-TTF) using electrocrystallisation technique and new semiconducting salts have been obtained with different phases as: a , et b.BREST-BU Droit-Sciences-Sports (290192103) / SudocSudocFranceF
Lanthanoid-Anilato Complexes and Lattices
In this review, we describe all the structurally characterized complexes containing lanthanoids (Ln, including La and group 3 metals: Y and Lu) and any anilato-type ligand (3,6-disubstituted-2,5-dihydroxy-1,4-benzoquinone dianion = C6O4X22−). We present all the anilato-Ln compounds including those where, besides the anilato-type ligand, there is one or more coligands or solvent molecules coordinated to the lanthanoid ions. We show the different structural types observed in these compounds: from discrete monomers, dimers and tetramers to extended 1D, 2D and 3D lattices with different topologies. We also revise the magnetic properties of these Ln-anilato compounds, including single-molecule magnet (SMM) and single-ion magnet (SIM) behaviours. Finally, we show the luminescent and electrochemical properties of some of them, their gas/solvent adsorption/absorption and exchange capacity and the attempts to prepare them as thin films
The Peter Day Series of Magnetic (Super)Conductors
Here, we review the different series of (super)conducting and magnetic radical salts prepared with organic donors of the tetrathiafulvalene (TTF) family and oxalato-based metal complexes (ox = oxalate = C2O42−). Although most of these radical salts have been prepared with the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF = ET), we also include all the salts prepared with other TTF-type donors such as tetrathiafulvalene (TTF), tetramethyl-tetrathiafulvalene (TM-TTF), bis(ethylenediseleno)tetrathiafulvalene (BEST), bis(ethylenedithio)tetraselenafulvalene (BETS) and 4,5-bis((2S)-2-hydroxypropylthio)-4′,5′-(ethylenedithio)tetrathiafulvalene (DMPET). Most of the oxalate-based complexes are monomers of the type [MIII(C2O4)3]3−, [Ge(C2O4)3]2− or [Cu(C2O4)2]2−, but we also include the reported salts with [Fe2(C2O4)5]4− dimers, [MII(H2O)2[MIII(C2O4)3]2]4− trimers and homo- or heterometallic extended 2D layers such as [MIIMIII(C2O4)3]− and [MII2(C2O4)3]2−. We will present the different structural families and their magnetic properties (such as diamagnetism, paramagnetism, antiferromagnetism, ferromagnetism and even long-range magnetic ordering) that coexist with interesting electrical properties (such as semiconductivity, metallic conductivity and even superconductivity). We will focus on the electrical and magnetic properties of the so-called Day series formulated as β″-(BEDT-TTF)4[A+MIII(C2O4)3]·G, which represents the largest family of paramagnetic metals and superconductors reported to date, with more than fifty reported examples
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