Search results for "Antiferromagnet"
showing 10 items of 506 documents
Nickel precursors based on diamagnetic and paramagnetic di(imine)pyridine ligands for magnetic materials: Synthesis, X-ray structures and magnetic st…
2018
International audience; Structural characterization and spectroscopic studies of the (2-acetyl-6-(1-TEMPO-imino)ethyl)pyridine (pat) and the 2,6-bis(1-TEMPO-imino)ethyl)pyridine (pbtMe) ligands are presented. Their electrochemical properties are also discussed. Two new nickel complexes, [NiII(dip)(CH3CN)(H2O)2](BF4)2 (1) (dip = 2,6-(di-iminepyridine)) and [NiII(pbtMe)(CH3CN)3](BF4)2 (2) have been characterized by X-ray diffraction. The reaction of 1 with the tetraethyl ammonium pentacyanopropenide salt (Et4N)(pcp) affords the new compound [NiII(pcp)(dip)(CH3CN)](pcp) (3) for which X-ray diffraction studies evidence an usual bridging μ2 coordination mode for the pentacyanopropenide anion, le…
Synthesis and Physical Properties of K4[Fe(C5O5)2(H2O)2](HC5O5)2·4H2O (C5O52– = Croconate): A Rare Example of Ferromagnetic Coupling via H-bonds
2012
The reaction of the croconate dianion (C(5)O(5))(2-) with a Fe(III) salt has led, unexpectedly, to the formation of the first example of a discrete Fe(II)-croconate complex without additional coligands, K(4)[Fe(C(5)O(5))(2)(H(2)O)(2)](HC(5)O(5))(2)·4H(2)O (1). 1 crystallizes in the monoclinic P2(1)/c space group and presents discrete octahedral Fe(II) complexes coordinated by two chelating C(5)O(5)(2-) anions in the equatorial plane and two trans axial water molecules. The structure can be viewed as formed by alternating layers of trans-diaquabis(croconato)ferrate(II) complexes and layers containing the monoprotonated croconate anions, HC(5)O(5)(-), and noncoordinated water molecules. Both …
Structures and Magnetic Properties of Bis(μ‐phenoxido), Bis(μ‐phenoxido)‐μ‐carboxylato and Bis(μ‐phenoxido)bis(μ‐carboxylato) Fe III Ni II Compounds …
2015
This report describes the syntheses, characterization, crystal structures and magnetic properties of five dinuclear FeIIINiII compounds derived from two Robson-type tetraiminodiphenol macrocyclic ligands H2L1 and H2L2, which are the [2+2] condensation products of 4-ethyl-2,6-diformylphenol and 1,3-diaminopropane (for H2L1) or 2,2-dimethyl-1,3-diaminopropane (for H2L2). The compositions of the compounds are [FeIII(N3)2L1NiII(H2O)2](ClO4) (1), [FeIII(benzoato)L1NiII(H2O)(μ1,3-benzoato)](ClO4) (2), [FeIII(benzoato)L2NiII(H2O)(μ1,3-benzoato)](ClO4) (3), [FeIIIL2NiII(μ1,3-acetato)2](ClO4)·H2O (4) and [FeIIIL2NiII(μ1,3-propionato)2](ClO4)·H2O (5). The bridging moieties between the two metal ions …
Magneto-structural studies on heterobimetallic malonate-bridged M(II)Re(IV) complexes (M = Mn, Co, Ni and Cu).
2010
The mononuclear Re(IV) compound of formula (PPh(4))(2)[ReBr(4)(mal)] (1) was used as a ligand to obtain the heterobimetallic species [ReBr(4)(μ-mal)Co(dmphen)(2)]· MeCN (2), [ReBr(4)(μ-mal)Ni(dmphen)(2)] (3), [ReBr(4)(μ-mal)Mn(dmphen)(2)] (4a), [ReBr(4)(μ-mal)Mn(dmphen)(H(2)O)(2)]·dmphen·MeCN·H(2)O (4b), [ReBr(4)(μ-mal)Cu(phen)(2)]·1/4H(2)O (5) and [ReBr(4)(μ-mal)Cu(bipy)(2)] (6) (mal = malonate dianion, dmphen = 2,9-dimethyl-1,10-phenanthroline, phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine). The structures of 2 and 5 (single-crystal X-ray diffraction) are made up of neutral [ReBr(4)(μ-mal)M(AA)] dinuclear units [AA = dmphen with M = Co (2) and AA = phen with M = Cu (5)] where the …
Unprecedented coexistence of cyano-bridged Mn4(III)Cr(III) and Mn2(III)Cr(III) heterobimetallic complexes in one single crystal.
2008
The penta-[{MnIII(4-MeO-salen)(H2O)(micro-CN)}4CrIII(CN)2]+ and trinuclear [{MnIII(4-MeO-salen)(H2O)(micro-CN)}2CrIII(CN)4](-) units coexist in 1 with weak antiferromagnetic interactions which are overcome by a dc magnetic field of 2.5 T.
Magnetic coupling in discrete cyano-bridged Mn(III)-Fe(III) motifs: synthesis, crystal structure, magnetic properties and theoretical study.
2010
The preparation, crystal structures and magnetic properties of the heterobimetallic complexes of formula [Mn(III)(n-MeOsalen)(H(2)O)(mu-CN)Fe(III)(bpym)(CN)(3)]·mH(2)O with n = m = 3 (1) and n = 4 and m = 2 (2) [n-MeOsalen(2-) = N,N'-ethylenebis(n-methoxysalicylideneiminate) dianion and bpym = 2,2'-bipyrimidine] are reported. 1 and 2 are dinuclear neutral species where the cyano-bearing low-spin unit [Fe(III)(bpym)(CN)(4)](-) acts as a monodentate ligand towards the [Mn(III)(SB)(solv)(x)](+) entity (SB = tetradentate Schiff-base) through one of its four cyano groups. Adjacent heterobimetallic units are interlinked through hydrogen bonds involving the coordinated water molecule of one dinucl…
K2MIII2(MVIO4)(PO4)2 (MIII = Fe, Sc; MVI = Mo, W), Novel Members of the Lagbeinite-Related Family: Synthesis, Structure, and Magnetic Properties
2012
The possibility of PO(4)(3-) for MoO(4)(2-) partial substitution in the langbeinite framework has been studied by exploration of the K-Fe(Sc)-Mo(W)-P-O systems using the high-temperature solution method. It was shown that 1/3PO(4)(3-) for MoO(4)(2-) substitution leads to formation of three novel compounds K(2)Fe(MoO(4))(PO(4))(2), K(2)Sc(MoO(4))(PO(4))(2), and K(2)Sc(WO(4))(PO(4))(2) with slightly increased lattice parameters and significant distortion of the anion tetrahedra without structure changes. In contrast, the antiferromagnetic structure is modified by substitution in the low-temperature region. The structural peculiarities are discussed in light of bond-valence sums calculations.
Synthesis, crystal structures and magnetic properties of cyanide- and phenolate-bridged [MIIINiII]2tetranuclear complexes (M = Fe and Cr)
2005
The binuclear complex NiII2L(H2O)2(ClO4)2 (1) and the neutral tetranuclear bimetallic compounds [{MIII(phen)(CN)4}2{NiII2L(H2O)2}]·2CH3CN with M = Fe (2) and Cr (3) [H2L = 11,23-dimethyl-3,7,15,19-tetraazatricyclo[19.3.1.19,13]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol] have been synthesized and the structures of 2 and 3 determined by single crystal X-ray diffraction. 2 and 3 are isostructural compounds whose structure is made up of centrosymmetric binuclear cations [Ni2(L)(H2O)2]2+ and two peripheral [M(phen)(CN)4]− anions [M = Fe (2) and Cr (3)] acting as monodentate ligands towards the nickel atoms through one of their four cyanide nitrogen atoms. The environment of t…
Structural, magnetic and related attributes of some oximate-bridged tetranuclear nickel(ii) rhombs and a dinuclear congenerElectronic supplementary i…
2003
New oximate-bridged tetranuclear nickel(II) complexes of compositions {Ni(Dien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·Solv (Solv = H2O, 1a; Solv = 2CH3NO2, 1b; Solv = 2H2O·2C4H8O2, 1c), {Ni(Sdien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·H2O (2), {Ni(Odien)}2(μ3-OH)2{Ni2(Moda)4}(ClO4)2·0.6H2O (3), {Ni(Dien)}2(μ3-OH)2{Ni2(Inaf)4}(ClO4)2·CH3NO2 (4) and {Ni(Odien)}2(μ3-OH)2{Ni2(Inaf)4}(ClO4)2·2NaClO4·2H2O (5) and the dinuclear complex (Ni{Odien})2(Moda)2(ClO4)2 (6) have been prepared (Dien = 1,5-diamino-3-azapentane, Odien = 1,5-diamino-3-oxapentane, Sdien = 1,5-diamino-3-thiapentane, ModaH = butane-2,3-dione monooxime, InafH = phenylglyoxaldoxime). X-ray examination revealed similar structures for 1a, 1b, 1c, 2 a…
A Novel Dinuclear Fe II Spin‐Crossover Complex Based on a 2,2‐Bipyrimidine Bridge Ligand: [Fe(CH 3 bipy)(NCS) 2 ] 2 bpym
2004
The dinuclear iron(II) complex {[Fe(CH3bipy)(NCS)2]2bpym} has been synthesised and its crystal structure determined at 293 K. The magnetic properties display intramolecular antiferromagnetic coupling at 1 bar (J = −4.2 cm−1), and the onset of a pressure-induced spin conversion is observed at 11 kbar. Magnetic field Mossbauer measurements have been carried out at 4.2 K, and indicate that the HS species correspond to [HS-HS] pairs. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)