Search results for "oxalate"
showing 10 items of 215 documents
Self-assembly of the tetrachlorido(oxalato)rhenate( iv ) anion with protonated organic cations: X-ray structures and magnetic properties
2016
Two novel ReIV compounds of formulae [H2bpy][ReIVCl4(ox)] (1) and [H3biim]2[ReIVCl4(ox)] (2) [H2bpy2+ = 4,4′-bipyridinium dication, H3biim+ = 2,2′-biimidazolium monocation, and ox2− = oxalate dianion] have been synthesised and magneto-structurally characterised. 1 crystallises in the monoclinic system with space group C2/c, and 2 crystallises in the triclinic system with space group P[1 with combining macron]. The ReIV ion in 1 and 2 is six-coordinate, bonded to four chloride ions and two oxalate-oxygen atoms in a distorted octahedral geometry. Short intermolecular ReIV–Cl⋯Cl–ReIV contacts, Cl⋯π type interactions and hydrogen bonds are present in the crystal lattice of both compounds, gener…
Supramolecular open-framework architectures based on dicarboxylate H-bond acceptors and polytopic cations with three/four N–H+donor units
2015
International audience; Supramolecular assemblages based on anionic H-acceptors and cationic H-donors have been envisioned to elaborate open frameworks maintained by ionic H-bonds. Combinations of di-anionic chloranilate (CA2-), oxalate (Ox2-), or terephthalate (BDC2-) and trisimidazolium or tetrapyridinium derivatives (three and four N-H+ donors, respectively) yielded five architectures of formulae [(H3TrIB)(CA)1.5[middle dot]2DMF[middle dot]2.5H2O] (1), [(H4Tetrapy)(CA)2[middle dot]3DMF] (2), [(H3TrIB)(HOx)(Ox)[middle dot]5H2O] (3), [(H4Tetrapy)(Ox)2[middle dot]5H2O] (4), and [(H4Tetrapy)(BDC)2(H2O)[middle dot]1DMF[middle dot]3H2O] (5) (with TrIB = 1,3,5-trisimidazolylbenzene and Tetrapy …
A hybrid magnet with coexistence of ferromagnetism and photoinduced Fe(iii) spin-crossover
2011
International audience; The insertion of a [Fe(sal2-trien)]+ complex cation into a 2D oxalate network results in a hybrid magnet with coexistence of magnetic ordering and photoinduced spin-crossover (LIESST effect) in compound [FeIII(sal2-trien)][MnIICrIII(ox)3]*(CH2Cl2) (1). A complete photomagnetic characterization together with a detailed structural analysis of the low-spin (LS) and high-spin (HS) structures of 1 is presented in order to understand such unusual behavior. This very rare and unexpected property in a FeIII spin-crossover complex, has been attributed to the strong distortion exhibited by the metastable HS state. Furthermore, 1 has shown that, in contrast to what has been pre…
Oxotris(oxalate)niobate(V): An oxalate delivery agent in the design of building blocks
2018
This work concerns the oxalate delivery process that occurs when using (NH4)3[NbO(C2O4)3]·6H2O as a suitable oxalate source in the synthesis of two compounds, [Cu(dmphen)(C2O4)(H2O)] (1) and [{Cu(dmphen)(CH3OH)}2(μ-C2O4)](ClO4)2 (2) (dmphen = 2,9-dimethyl-1,10-phenanthroline). {[Fe{HB(pz)3}(CN)2(μ-CN)]2[{Cu(dmphen)}2(μ-C2O4)]}∙xCH3OH (3) (2.0 ≤ x ≤ 2.4) was obtained by reacting 2 and PPh4[Fe{HB(pz)3}(CN)3]∙H2O [ = tetraphenylphosphonium and = tris(pyrazolyl)borate]. Crystal structures of 1–3 have been determined by single-crystal X-ray diffraction experiments: 1 is a mononuclear trigonal bipyramidal copper(II) species, 2 is a centrosymmetric oxalato-bridged dicopper(II) complex, and 3 consi…
Hydrogen-Bonded Open-Framework with Pyridyl-Decorated Channels: Straightforward Preparation and Insight into Its Affinity for Acidic Molecules in Sol…
2017
International audience; An hydrogen-bonded open framework with pores decorated by pyridyl groups has been constructed following an off-charge-stoichiometry assemblage of protonated tetrakis(4-pyridyl-oxymethyl)methane and [Al(oxalate)3]3-, respectively the H-bond donor and acceptor of the ionic H-bond interactions. This supramolecular porous architecture (SPA-2) possesses 1 nm-large pores interconnected in 3D with high solvent accessible void (53%). It demonstrated remarkable affinity for acidic organic molecules in solution, which was investigated by the means of various carboxylic acids including larger drug molecules. Noteworthy, competing sorption between acetic acid and its halogenated…
Heterobimetallic Oxalate‐Bridged M II Re IV (M = Zn, Cu, Ni, Co and Mn) Complexes Incorporating Bis(3,5‐dimethylpyrazol‐1‐yl)methane: Synthesis and M…
2016
Five oxalato-bridged heterobimetallic compounds of general formula [ReCl4(ox)M(bdmpzm)2].2MeCN [ox = oxalate, bdmpzm = bis(3,5-dimethylpyrazol-1-yl)methane and M = Zn (1),Cu (2), Ni (3), Co (4) and Mn (5)] have been successfully synthesized in self-assembly reactions of the [ReCl4(ox)]2- metalloligand with the coordinatively unsaturated [M(bdmpzm)2]2+ complex generated in situ by the reaction of the suitable metal(II) salt with the bdmpzm ligand. 1-5 are isostructural compounds whose crystal structures consist of neutral heterodinuclear [ReCl4(ox)M(bdmpzm)2] units and free acetonitrile molecules. The magnetic properties of 1-5 were investigated in the temperature range 2.0-300 K. The nature…
Design of bimetallic magnetic chains based on oxalate complexes: towards single chain magnets
2009
We describe the synthesis, structure and magnetic characterization of several oxalate-based bimetallic 1D systems. We will exemplify how by suitable choice of the molecular building blocks and strict control of their arrangement in the solid state, the magnetic properties of these low-dimensional materials can be tuned to finally obtain bimetallic oxalate chains behaving as single-chain magnets (SCM). First, we will focus on compounds [K(18-crown-6)][MII(bpy)Cr(ox)3] (1, 2; MII = Mn, Co; bpy = C10N2H8). The MnCr derivative behaves as a 1D ferromagnet down to 2 K, the lowest investigated temperature. The lack of magnetic ordering in this chain prompted us to prepare the more anisotropic MnCo…
Photomagnetic properties of an Fe(ii) spin-crossover complex of 6-(3,5-diamino-2,4,6-triazinyl)-2,2'-bipyridine and its insertion into 2D and 3D bime…
2017
International audience; The Fe(ii) complex of the L1 ligand (L1 = 6-(3,5-diamino-2,4,6-triazinyl)-2,2'-bipyridine) has been used as a templating cation for the growth of oxalate-based networks. The magnetic characterization of the [Fe(II)(L1)2](ClO4)2·CH3CN (1) precursor in the solid state has been performed for the first time showing that the low-spin (LS) state is predominating from 2 to 400 K with 10% of Fe(ii), which undergoes a gradual and irreversible spin-crossover above 350 K. 1 presents the LIESST effect with a photo-conversion close to 25% and a T(LIESST) of 49 K. During the preparation of 1, a secondary product of the formula [Fe(II)(L1)(CH3CN)2(H2O)](ClO4)2·CH3CN (2) has been ob…
Highly Anisotropic Rhenium(IV) Complexes: New Examples of Mononuclear Single-Molecule Magnets
2013
The rhenium(IV) complex (NBu4)2[ReBr4(ox)] (1) (ox = oxalate and NBu4(+) = tetra-n-butylammonium cation) has been prepared and its crystal structure determined by X-ray diffraction. The structure is made up of discrete [ReBr4(ox)](2-) anions and bulky NBu4(+) cations. Each [ReBr4(ox)](2-) anion is surrounded by six NBu4(+) cations, which preclude any significant intermolecular contact between the anionic entities, the shortest rhenium···rhenium distance being 9.373(1) Å. Variable temperature dc and ac magnetic susceptibility measurements and field-dependent magnetization experiments on polycrystalline samples of 1 reveal the occurrence of highly anisotropic magnetically isolated Re(IV) cent…
Synthesis, crystal structure and magnetic properties of two oxalato-bridged dimetallic trinuclear complexes combined with a polar cation
2010
Two isostructural heterometallic trinuclear oxalato-bridged complexes of formula C(4)[MCr(2)(ox)(6)(H(2)O)(2)]·nH(2)O (C(+) = 4-aminopyridinium; ox(2-) = oxalate dianion; M(2+) = Mn(2+), n = 3, 1; M(2+) = Co(2+), n = 3.25, 2) have been synthesized by using direct self-assembly methods combining C(3)[Cr(ox)(3)] and the chloride salts of the corresponding metal ion. The crystal structures of both compounds have been resolved by single-crystal X-ray diffraction. They crystallize in the C2/c space group [a = 11.5113(15) Å, b = 20.250(3) Å, c = 21.810(4) Å, beta = 100.447(10) degrees, V = 5161.6(3) Å(3), and Z = 4 for 1, and a = 11.4334(16) Å, b = 20.243(2) Å, c = 21.805(3) Å, beta = 101.113(9) …