Search results for "Magnetic Susceptibility"
showing 10 items of 516 documents
A unique single carboxylate-bridged spin-frustrated chiral Mn(II) metallatriangle.
2010
The reaction between Hmbpymca ligand (prepared in situ from the hydrolysis of 5-methyl-4-cyano-bispyrimidine with NaOH and further neutralization with 2 M HCl) and Mn(ClO(4))(2)·4H(2)O in 1:1 molar ratio afforded the triangulo-trimanganese(II) complex [Mn(3)(bpymca)(3)(H(2)O)(6)]Cl(3)·6H(2)O 1. The chloride anions in this complex come from the HCl used in the neutralization process. The molecular structure of 1 consists of cationic molecular triangles [Mn(3)(μ-mbpymca)(3)(H(2)O)(6)](3+) with C(3) symmetry, chloride anions and crystallization water molecules, all of them involved in an extensive network of hydrogen bonds, leading to a chiral network. Within the [Mn(3)(μ-mbpymca)(3)(H(2)O)(6)…
Synthesis, Structure, and Magnetic Properties of a Tris[3-(2-pyridyl)-1,2,4-triazole]iron(II) Spin-Crossover Complex
2000
The synthesis and characterization of tris[3-(pyridin-2-yl)-1,2,4-triazole]iron(II) bis(tetrafluoroborate), obtained from the reaction of 3-(pyridin-2-yl)-1,2,4-triazole (Hpt) and hexaaquairon(II) tetrafluoroborate, [Fe(H2O)6](BF4)2, is described, together with its crystal structures at two temperatures. X-ray crystallographic parameters are as follows: [Fe(Hpt)3](BF4)2·nH2O (n ≈ 2) at 250 K: orthorhombic space group Pbam, a = 15.8068(18) A, b = 17.2800(14) A, c = 21.215(2) A, V = 5794.7(10) A3, and Z = 8. [Fe(Hpt)3](BF4)2·nH2O (n ≈ 2) at 95 K: orthorhombic space group Pbam, a = 15.7080(12) A, b = 17.1023(16) A, c = 21.006(2) A, V = 5643.1(9) A3, and Z = 8. The FeII ions are (at both temper…
Prediction of Magnetic Properties in Oxovanadium(IV) Phosphates: The Role of the Bridging PO4 Anions
1998
Oxovanadium phosphates constitute a crystallochemically very rich family that, in turn, results in a seemingly intricate magnetochemistry including from isolated dimers to 3-D systems. This magnetic diversity is due, in part, to the possible participation of phosphate groups in the spin transfer between VIV centers. This way, 31P solid-state NMR becomes a key tool in determining the exchange paths involving phosphorus orbitals. The magnetic behavior of several layered oxovanadium phosphates M(VOPO4)2·4H2O (M = Na+, Ca2+, Ba2+, and Pb2+) has been investigated. Like it occurs in the case of other previously studied lamellar derivatives, the best fit of the temperature-dependent magnetic susce…
Towards a better understanding of honeycomb alternating magnetic networks.
2015
Two new two-dimensional homometallic compounds {[M2(bpm)(ox)2]n·5nH2O} with M = Co(II) (1) and Zn(II) (2) and the mononuclear nickel(II) complex [Ni(bpm)2(ox)]·2H2O (3) [bpm = 2,2'-bipyrimidine and ox = oxalate] have been prepared and structurally characterized. 1 and 2 are isostructural compounds whose structures are made up of oxalate-bridged M(II) cations cross-linked by bis-bidentate bpm molecules to afford a honeycomb layered network extending in the crystallographic ab plane. The layers are eclipsed along the crystallographic c axis and show graphitic-like interactions between the bpm rings. The three-dimensional supramolecular network deriving from such interactions is characterized …
The Iron Hydrido Complex [FeH(dppe)2]+: Solution and Solid-State Reactivity with Dinitrogen
2006
The blue compound [FeH(dppe)2]BPh4 (1) (dppe = 1,2-bis(diphenylphosphino)ethane) is investigated by optical absorption, vibrational, NMR and Mossbauer spectroscopy as well as magnetic susceptibility measurements. In the solid state, 1 is found to be paramagnetic (S=1) whereas in tetrahydrofuran (thf) solution it is diamagnetic. Importantly, 1 reacts with dinitrogen in thf solution and in the solid state to give the yellow and green dinitrogen complexes 2a and 2b, respectively, both of which have the formula [FeH(N2)(dppe)2]BPh4. Apart from their colour and optical spectroscopic properties, the dinitrogen compounds 2a and 2b also differ in their magnetic, Mossbauer and vibrational properties…
A two-dimensional radical salt based upon BEDT-TTF and the dimeric, magnetic anion [Fe(tdas)2]22−: (BEDT-TTF)2[Fe(tdas)2] (tdas = 1,2,5-thiadiazole-3…
2002
In an attempt to synthesize new synthetic metals which couple magnetic properties to conductivity, we prepared the novel salt (BEDT-TTF)2[Fe(tdas)2] [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, hereafter referred to as ET; tdas = 1,2,5-thiadiazole-3,4-dithiolate] by the electrocrystallization technique. The crystal structure of this compound, as determined by single crystal X-ray diffraction, contains conducting, organic ET layers separated by dimerized, magnetic [Fe(tdas)2]22− anions. Due to the magnetic insulating ground electronic state of the ET layer, thermally activated conductivity is observed, with a room temperature value of about 1 S cm−1. This salt was also characterized by…
Hybrid Molecular Materials Based upon Organic π-Electron Donors and Metal Complexes. Radical Salts of Bis(ethylenethia)tetrathiafulvalene (BET-TTF) w…
2001
The synthesis, structure, and physical characterization of two new radical salts formed with the organic donor bis(ethylenethia)tetrathiafulvalene (BET-TTF) and the octahedral anions hexacyanoferrate(III), [Fe(CN)(6)](3-), and nitroprusside, [Fe(CN)(5)NO](2-), are reported. These salts are (BET-TTF)(4)(NEt(4))(2)[Fe(CN)(6)] (1) (monoclinic space group C2/c with a = 38.867(7) A, b = 8.438(8) A, c = 11.239(6) A, beta = 90.994(9) degrees, V = 3685(4) A(3), Z = 4) and (BET-TTF)(2)[Fe(CN)(5)NO].CH(2)Cl(2) (2) (monoclinic space group C2/c with a = 16.237(6) A, b = 18.097(8) A, c = 12.663(7) A, beta = 106.016(9) degrees, V = 3576(3) A(3), Z = 4). In salt 1 the organic BET-TTF molecules are packed …
Synthesis, Characterization and Magnetic Properties of New Dinuclear Copper(II) Complexes with N,N′-Disubstituted Dithiooxamides derived from α-Amino…
2005
Four new dinuclear copper(II) complexes have been synthesized and have the general formula [Cu2(L)(H2O)2], where L = GLYDTO [N,N′-bis(carboxymethyl)dithiooxamide], ALADTO [N,N′-bis(carboxyethyl)dithiooxamide], VALDTO [N,N′-bis(1-carboxy-2-methylpropyl)dithiooxamide] and LEUDTO [N,N′-bis(1-carboxy-3-methylbutyl)dithiooxamide]. The complexes were characterized by elemental analysis as well as by IR, electronic and EPR spectroscopy. These techniques provided evidence for the presence of the CuNO2S chromophore. Magnetic susceptibility measurements on all the complexes in the range 4–300 K show the existence of a dominant antiferromagnetic interaction with −J values greater than 300 cm−1. Therma…
Synthesis, X-ray crystal structure and magnetic study of a dicyanamido bridged 1D chain nickel(II) complex
2008
Abstract Reaction of Ni(NO3)2 · 6H2O and sodium dicyanamide (Nadca) yields a 1D infinite chain complex {[Ni(dien)(μ1,5-dca)(H2O)](NO3)}n (1) (where dien = diethylenetriamine). The coordination environment in complex 1 around the nickel(II) ions is distorted octahedron. Three nitrogen atoms of the ligand diethylenetriamine and an oxygen atom of H2O molecule constitute the four coordination sites of the basal plane of the octahedron. Of two axial positions of the octahedron, one position is occupied by the nitrogen atom of a μ1,5-dca anion the remaining coordination site is occupied by a nitrogen atom of another end-to-end bridging dca from an adjacent [Ni(dien)(μ1,5-dca)(H2O)] moiety, yieldi…
Ligand substitution in hexahalorhenate(IV) complexes: Synthesis, crystal structures and magnetic properties of NBu4[ReX5(DMF)] (X=Cl and Br)
2006
Abstract The preparation, crystal structures, and magnetic properties of two rhenium(IV) mononuclear compounds of formula NBu 4 [ReX 5 (DMF)] ( NBu 4 + = tetrabutylammonium cation and DMF = N , N - dimethylformamide ) with X = Cl ( 1 ) and Br ( 2 ) are reported. 1 and 2 are isostructural complexes which crystallize in the monoclinic system with the space group P 2 1 / n . The rhenium atom is six-coordinated with five X atoms and a DMF molecule forming a somewhat distorted octahedral surrounding [values of Re–X varying in the ranges 2.317(1)–2.358(1) ( 1 ) and 2.495(1)–2.518(1) A ( 2 )]. Magnetic susceptibility measurements on samples of 1 and 2 in the temperature range 1.9–300 K are interpr…