共查询到20条相似文献,搜索用时 31 毫秒
1.
《Inorganica chimica acta》2006,359(5):1582-1588
The crystal and molecular structure of a new 2-methylquinolinium [2-Me(QH)] salt of stoichiometry (2-Me(QH))2FeBr5 was determined. The iron cation is four coordinated by bromine anions, and it adopts a slightly distorted tetrahedral coordination with two angles smaller than tetrahedral, two equal to tetrahedral and two larger than tetrahedral. In the structure two intermolecular N–H⋯Br hydrogen bonds link the 2-MeQH+ cations to dimers via a Br− bridge. The compound is isostructural with its chloride analog, (2-Me(QH))2FeCl5. Magnetic measurements of the powdered samples gave negative values of Weiss constants equal −3.1 K for (2-Me(QH))2FeCl5 and −10.2 K for (2-Me(QH))2FeBr5 that suggest antiferromagnetic coupling. The susceptibility curves for (2-Me(QH))2FeBr5 exhibit a maximum at 6 K indicating the presence of antiferromagnetic interactions transmitted in the crystal lattice. 相似文献
2.
A series of tetramethylammonium tetrahalogenoferrates(III), [FeBr4−nCln]− (n = 0, 1, 3, 4), of general formula [(CH3)4N][FeBr4−nCln], have been synthesized. The crystal and molecular structures of [(CH3)4N][FeCl4] were determined. The compound is isostructural with its [FeBr4−nCln]− (n = 0, 1, 3, 4) analogues. Magnetic measurements of the powdered samples of [(CH3)4N][FeBr4−nCln] gave negative values of the Weiss constant, which suggest antiferromagnetic coupling. The strength of the antiferromagnetic interactions strongly depends on the kind of halide ligands in the coordination sphere of iron(III) and increases with an increasing number of the bromide anions. 相似文献
3.
Bryan C.K. Chan 《Inorganica chimica acta》2004,357(9):2776-2782
Reaction of anhydrous FeCl2 with 6,6′-dimethyl-2,2′-bipyridyl (dmby) in non-aqueous media gives the yellow, high spin, tetrahedral complex FeCl2(dmby), which is characterized crystallographically, magnetically and by 1H NMR spectroscopy. In contrast, reaction of FeCl2 · 4H2O with dmby in 0.1 M hydrochloric acid, the method of choice for preparing 3:1 and 2:1 iron(II) complexes of 2,2′-bipyridyl, gives [H2dmby][FeCl4] and [Hdmby][FeCl4], in which the dmby has been protonated. These complexes are also characterized crystallographically. 相似文献
4.
《Inorganica chimica acta》2001,312(1-2):88-92
4-Piperidinylpyridine and FeCl3 in CH3CN/conc. HCl yield the title compound, whose crystal structure shows almost tetrahedral [FeCl4]− anions, and cations exhibiting the pyridinium tautomer. The temperature dependence of the Mössbauer spectra and AC susceptibility confirm a Néel temperature of approximately 2.5 K and an uncanted three-dimensional antiferromagnetic ground state. 相似文献
5.
Xing Chen Hai-Lian Zhou Qian Huang Le-Min Yang Xue-Lei Hu 《Inorganica chimica acta》2010,363(14):4024-4030
Syntheses, crystal structures and magnetic properties of two salts, [FBzTPP][Ni(mnt)2](1) and [FBzTPP]2[Cu(mnt)2](2) ([FBzTPP]+ = 1-(4′-fluorobenzyl)triphenylphosphinium, mnt2− = maleonitriledithiolate), are investigated. In 1, the anions and cations stack into well-segregated columns, and the Ni(III) ions form a 1D alternating chain in a [Ni(mnt)2]− column through intermolecular Ni?S and π?π interactions with the Ni?Ni distances of 3.939, 4.057 and 4.101 Å, and the C-H?N hydrogen bonds are found between the [Ni(mnt)2]− anion and the neighboring [FBzTPP]+ cation. The [Cu(mnt)2]2− anions in 2 do not form a column and no weak interactions exist between the anions duo to isolation of the [FBzTPP]+ cations, while C-H?F and C-H?S hydrogen bonds were found in 2. Magnetic susceptibility measurements in the temperature range 2-300 K show that 1 exhibits a spin-gap transition around 46 K, and antiferromagnetic interaction (θ = −49.0 K) in the high-temperature phase (HT) and spin gap (Δ/kb = 88.2 K) in the low-temperature phase (LT), while 2 shows a very weak antiferromagnetic coupling behavior with θ = −1.33 × 10−2 K. 相似文献
6.
Tanmay K. Jana Rabindranath Pradhan Subhajit Dinda Corine Simonnet Inhar Imaz Léopold Fournès Francis Sécheresse Ramgopal Bhattacharyya 《Inorganica chimica acta》2009,362(10):3583-3594
Iron (II) and iron (III) complexes, [FeII(DEDTC)2(dppe)] · CH2Cl2 (1), [FeII(ETXANT)2(dppe)] (2) (DEDTC = diethyldithiocarbamate, ETXANT = ethyl xanthate, dppe = 1,2-bis (diphenylphosphino) ethane), and [FeIII(DEDTC)2(dppe)] [FeIIICl4] (3) have been synthesized and characterized. Since 3 contains two magnetic centers, an anion metathesis reaction has been conducted to replace the tetrahedral FeCl4− by a non-magnetic BPh4− ion producing [FeIII(DEDTC)2(dppe)]BPh4 (4) for the sake of unequivocal understanding of the magnetic behavior of the cation of 3. With the similar end in view, the well-known FeCl4− ion, the counter anion of 3, is trapped as PPh4[FeIIICl4] (5) and its magnetic property from 298 to 2 K has been studied. Besides the spectroscopic (IR, UV-Vis, NMR, EPR, Mass and XPS) characterization of the appropriate compounds, especially 2, others viz. 1, 3 and 4 have been structurally characterized by X-ray crystallography. While FeII complexes, 1 and 2, are diamagnetic, the FeIII systems, namely the cations of 3, and 4 behave as low-spin (S = 1/2) paramagnetic species from 298 to 50 K. Below 50 K 3 shows gradual increase of χMT up to 2 K suggesting ferromagnetic behavior while 4 exhibits gradual decrease of magnetic moment from 60 to 2 K, indicating the occurrence of weak antiferromagnetic interaction. These conclusions are supported by the Mössbauer studies of 3 and 4. The Mössbauer pattern of 1 exhibits a doublet site for diamagnetic (2-400 K) FeII. The compounds 1, 2 and 4 encompass interesting cyclic voltammetric responses involving FeII, FeIII and FeIV. 相似文献
7.
Larysa Penkova Vadim A. Pavlenko Franc Meyer Igor O. Fritsky 《Inorganica chimica acta》2010,363(12):3036-8436
The synthesis, crystal structure and magnetic properties of manganese(III) binuclear complexes [MnIII2(L-3Н)2(CH3ОH)4]·2CH3ОH (1) and [MnIII2(L-3Н)2(Py)4]·2Py (2) (L = 3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid) are reported. The ligand contains two distinct donor compartments formed by the pyrazolate-N and the oxime or the carboxylic groups. The complexes were characterized by X-ray single crystal diffraction, revealing that both 1 and 2 consist of dinuclear units in which the two metal ions are linked by double pyrazolate bridges with a planar {Mn2N4} core. Cryomagnetic measurements show antiferromagnetic interaction with g = 1.99, J = −3.6 cm−1, Θ = −2.02 K for 1 and g = 2.00, J = −3.7 cm−1, Θ = 1.43 K for 2. 相似文献
8.
Kil Sik Min 《Inorganica chimica acta》2007,360(6):1854-1858
The reaction of [FeII(H2O)6](BF4)2 with tris(2-pyridylmethyl)amine (TPyA) and triethylamine in methanol under aerobic conditions forms [(TPyA)FFeIIIOFeIIIF(TPyA)](BF4)2 · 0.5MeOH (1), in which each Fe(III) ion is coordinated to a TPyA and an F− ion as well as an oxo ion (O2−) linking two Fe(III) ions. 1 has offset face-to-face π-π interactions between the dimers, and possesses a supramolecular network structure. The magnetic susceptibility of 1 can be fit with g = 2.0, J/kB = − 153 K (106 cm−1), and θ = − 0.3 K [H = − 2JSa · Sb]. These indicate that very strong antiferromagnetic interactions occur via the oxo bridge within the Fe(III) dimer and weak antiferromagnetic interactions between the dimers. 相似文献
9.
An oxalato-bridged binuclear iron(III) compound, Fe2(C2O4)Cl4(DMF)4 (DMF = dimethylformamide), was obtained by electrocrystallization for three weeks at 3.4 V and it displays a strong antiferromagnetic interaction of J = −6.74(4) cm−1. 相似文献
10.
Nans Roques Daniel Maspoch Angela Datcu Jean-Pascal Sutter Jaume Veciana 《Inorganica chimica acta》2007,360(13):3861-3869
Two europium (III) complexes (3 and 4) have been obtained reacting europium (III) nitrate and two polychlorotriphenylmethyl radicals properly functionalized with one (PTMMC−, 1) and six (PTMHC6−, 2) carboxylate groups, respectively. While complex 3 reveals a lamellar polar-apolar separated ion pair structure alternating PTM-based bilayers with nonaaquaeuropium cations ([Eu(H2O)9](PTMMC)3(PTMMCH)3 · 7H2O · 6EtOH), complex 4 shows a one-dimensional chain-like structure with formula [Eu2(PTMHC)(H2O)13] · 16H2O · EtOH. Magnetic properties of both complexes were studied in the 2-300 K range, and show the presence of weak inter-radical antiferromagnetic interactions below 5 K. 相似文献
11.
Olivier Jeannin 《Inorganica chimica acta》2007,360(13):3820-3824
Two closely related 1:1 salts are obtained upon electrocrystallization of BEDT-TTF (BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene) in the presence of the isosteric [M(tfadt)2]− dithiolene complexes (tfadt: 1-trifluoromethyl-2-cyano-1,2-dithiolato), which essentially differ by their spin state, S = 0 in [Au(tfadt)2]−, S = 1/2 in [Ni(tfadt)2]−. In both [BEDT-TTF][M(tfadt)2] salts, the BEDT-TTF radical cations form chains with a strong lateral overlap and strong antiferromagnetic interactions while the paramagnetic anions in the nickel-containing salt [BEDT-TTF][Ni(tfadt)2] are essentially non-interacting. The structural differences between the nickel and gold complexes are analyzed and discussed. 相似文献
12.
Tetranuclear Cu(II) complexes of N-(2-hydroxymethylphenyl)salicylideneimine (H2L1-H) and its homologues (5-CH3: H2L1-Me, 5-Cl: H2L1-Cl), [Cu(L1-H)]4 · 3H2O (1), [Cu(L1-Me)]4 · 2CH2Cl2 (2), and [Cu(L1-Cl)]4 · 2CH2Cl2 (3), have been characterized by X-ray crystal structure analyses and magnetic measurements. The structure analyses revealed that the complexes 1-3 have a defective double-cubane tetra copper(II) core connected by μ3-alkoxo bridges. The intramolecular Cu?Cu distances are in the range from 5.251(2)-5.256(3) Å for the longest to 3.0518(9)-3.092(2) Å for the shortest. Each Cu(II) ion has a square-pyramidal geometry and the dihedral angles between adjacent Cu(II) basal planes are almost right angles. Magnetic measurements of the present complexes indicate that weak antiferromagnetic interactions (J=−15 to −19 cm−1) between neighboring copper(II) ions are dominant in these tetracopper cores. 相似文献
13.
Toshiaki Tsukuda 《Inorganica chimica acta》2005,358(4):1253-1257
Synthesis, characterization and magnetic properties of new lanthanide-radical complexes, [LnIII(hfac)3(IM2imH)] (Ln = Gd, Tb; IM2imH = 2-(2-pyridyl)-4,5-dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy), are described. The molecular structure of the [Tb(hfac)3(IM2imH)] has been determined by the X-ray diffraction. The magnetic susceptibility data for [Gd(hfac)3(IM2imH)] show that the Gd-IM2imH magnetic interaction is antiferromagnetic with an exchange coupling constant J = −2.59 cm−1 in contrast to the ferromagnetic interaction in most of Gd(III) complexes containing paramagnetic center, which will be examined in connection with planarity of the IM2imH chelate. 相似文献
14.
A tetranuclear Cu(II) complex [Cu4L4(H2O)4](ClO4)4 has been synthesized using the terdentate Schiff base 2-(pyridine-2-yliminomethyl)-phenol (HL) (the condensation product of salicylaldehyde and 2-aminopyridine) and copper perchlorate. Chemical characterizations such as IR and UV/Vis of the complex have been carried out. A single-crystal diffraction study shows that the complex contains a nearly planar tetranuclear core containing four copper atoms, which occupy four equivalent five-coordinate sites with a square pyramidal environment. Magnetic measurements have been carried out over the temperature range 2-300 K and with 100 Oe field strengths. Analysis of magnetic susceptibility data indicates a strong antiferromagnetic (J1 = −638 cm−1) exchange interaction between diphenoxo-bridged Cu(II) centers and a moderate antiferromagnetic (J2 = −34 cm−1) interaction between N-C-N bridged Cu(II) centers. Magnetic exchange interactions (J’s) are also discussed on the basis of a computational study using DFT methodology. The spin density distribution (singlet ground state) is calculated to visualize the effect of delocalization of spin density through bridging groups. 相似文献
15.
Masayoshi Onishi Koh-hei Kayano Hitoshi Yamaguchi Yasuhiro Arikawa 《Inorganica chimica acta》2004,357(14):4091-4101
Although reactions of samarium(III) chloride, SmCl3 · 6H2O, with potassium hydrotris(1-pyrazolyl)borate K[BH(pz)3] (pz = 1-pyrazolyl) in a molar ratio of (1/1) in THF afford [SmCl{BH(pz)3}2(Hpz)], similar reactions with K[B(pz)4] gave rise to separation of anhydrous H[B(pz)4]. The homoleptic eight-coordinate complex [Sm{B(pz)4}3] obtained from SmCl3 · 6H2O and threefold moles of K[B(pz)4] was allowed to react with twofold moles of K[BH(pz)3] to give a mixture of three major species [Sm{B(pz)4}n{BH(pz)3}(3 − n)] (n = 2, 1, 0), whereas similar reactions of [Sm{BH(pz)3}3] with K[B(pz)4] did not proceed at all. The acetylacetonato (acac) complex [Sm{B(pz)4}2(acac)], derived from the triflate “Sm{B(pz)4}2(OTf)”, was treated with twofold moles of K[BH(pz)3] and showed its quantitative conversion to [Sm{BH(pz)3}2(acac)]. However, analogous reaction of [Sm{BH(pz)3}2(acac)] with K[B(pz)4] did not proceed. Accordingly, samarium(III) ion was determined to prefer coordination of BH(pz)3 ligand to that of B(pz)4, indicating less σ-donating electronic character of the latter. The complexes [Sm{B(pz)4}2(L-L)] (L-L = β-ketoenolato) in toluene-d8 exhibited 1H NMR spectroscopic equivalence of all four pyrazolyl groups at high temperatures, and are regarded as a new class of B(pz)4 complexes, showing fast intramolecular exchange of their coordinated and uncoordinated pyrazolyl groups. Four compounds were crystallographically characterized. 相似文献
16.
Two new mononuclear Fe(III) complexes, [FeCl3{PPh2(p-C6H4NMe2)-P}3](1) (PPh2(p-C6H4NMe2): 4-(dimethylamino)phenyldiphenylphosphine) and [FeCl3(PPh2py-P)(PPh2py-P,N)] (2) (PPh2py: diphenyl(2-pyridyl)phosphine) were synthesized by reacting anhydrous FeCl3 with respective ligand in acetonitrile solution under refluxing condition. Both the complexes were characterized by elemental analysis, FAB-Mass, FTIR, UV-Vis, ESR, Cyclic Voltammetry and magnetic measurement. The FAB mass spectra of complexes 1 and 2 show molecular ion peak at m/z 1078 [M]+ and m/z 687 [M−1]+, respectively, indicating mononuclear nature of the complexes. UV-Vis spectra of the complexes were consistent with low-spin, octahedral geometry. The variable temperature magnetic susceptibility measurement (73-323 K) of these complexes is also consistent with the paramagnetic nature of the complexes with a ground state spin S = ½. The Fe(III) centers of these two complexes remain low-spin, both at room temperature and liquid nitrogen temperature, was also indicated by the ESR analysis. Cyclic Voltammetry of both the complexes show an irreversible oxidation wave attributed to Fe3+ → Fe4+ + e− along with the peak for ligand oxidation. Theoretical calculations (B3LYP) of the complexes show that for complex 1, a trans geometry of the two phosphorous atoms and for complex 2, a mer,cis structures are the most favored geometrical isomer. TDDFT calculations were performed to interpret the observed bands in the UV-Visible spectra. 相似文献
17.
A new pyridyl-carboxylate ligand, the anion of trans-4-cotininecarboxylic acid, HL, 1, has been used to prepare a new polymeric copper(II) complex, [CuLN3]2n, 2, based on a [CuLN3]2 dimeric building block. The single crystal structures of both 1 and 2 have been determined and 1 has been found to be in its zwitterionic configuration. The structure of 2 is a one-dimensional tape-like polymeric structure based on an end-on azido-bridged binuclear [Cu2N3]2 backbone moiety. Magnetic studies reveal that 2 is close to paramagnetic from 2 to 300 K with a Curie constant of 1.094 emu K/mol, a Weiss temperature of 0.73 K and a corresponding μeff of 2.09 μB. A fit of χMT for 2 with S1 = S2 = ½, yields g = 2.441(6), J = −0.49(3) cm−1, zJ = −0.38(2) cm−1 and N(α) = 0.00053(12) emu/mol, a fit that indicates the presence of both very weak intramolecular intrachain antiferromagnetic exchange coupling within the one-dimensional tape-like chains and very weak interchain antiferromagnetic exchange coupling between these chains. 相似文献
18.
The cobalt(II) complexes [Co(TPA)Cl]ClO4 (1), [Co(TPA)Br]ClO4 (2), [Co(TPA)(H2O)]Cl(ClO4) (3) and [Co2(TPA)2(μ-tp)](ClO4)2 · 2H2O (4) (TPA = tris(2-methylpyridyl)amine and tp = terephthalate dianion) were synthesized and structurally characterized by UV-vis and IR spectroscopy. The molecular structures of complexes 1 and 4 were determined by X-ray crystallography and their magnetic properties were measured over the temperature range 2-300 K. The coordination geometry around the central Co(II) in these compounds has a distorted trigonal bipyamidal geometry with four nitrogen atoms from the TPA ligand and the fifth coordination site is occupied by Cl− ion in 1, Br− ion in 2, coordinated oxygen atom from H2O in 3 and by an oxygen atom supplied by the carboxylate group of the bridged terephthalato ligand in 4. The visible spectra of the complexes 1-3 in MeOH show strong distortion toward tetrahedral geometry. For complex 4, analysis of the infrared spectral data for the ν(COO−) stretching frequencies of the tp-carboxalato groups reveals the existence of the bis(monodentate) coordination mode for the bridged tp. X-ray data for 1 and 4 show that the former is mononuclear while the latter is dinuclear. The electronic spectrum of 4 in MeOH is in complete agreement with the assigned X-ray geometry around the Co(II) centers. The magnetic behavior of the mononuclear complex 1 is indicative of a high-spin compound with zero-field splitting. The best fit was obtained with ∣D∣ = 7.3 cm−1, g = 2.25. The dinuclear complex 4 exhibits weak antiferromagnetic coupling with a coupling constant J = −0.8 cm−1. The magnetic properties and the structural parameters of 4 are discussed in relation to the other related μ-terephthalato dinuclear Co(II) compounds. The geometry of the coordination sphere around 4 is unique - the CSD compilation listing only one other compound with such a geometry around the dinuclear Co(II) complex and its composition is far different from that in 4. However, they share a common feature of having a weakly antiferromagnetic coupling between Co(II) centers. 相似文献
19.
Two novel molecular magnetic materials, [RBzTPP][Ni(mnt)2] (mnt2− = maleonitriledithiolate, [RBzTPP]+ = 4-R-benzyltriphenylphosphinium; R = CN (1), Cl (2)) were synthesized and characterized by X-ray diffraction, IR spectroscopy, and magnetic susceptibility measurements. In crystal of 1, the [Ni(mnt)2]− anions form a dimer via Ni?S and π?π stacking interactions between Ni(mnt)2 planes, and the C-H?Ni and C-H?N H-bonding interactions are found between the [Ni(mnt)2]− anions and the neighboring [CNBzTPP]+ cations. The anions and cations of 2 stack into well-segregated columns in the solid state; and the Ni(III) ions form a 1D alternating chain in a Ni(mnt)2 column through intermolecular Ni?S, or π?π interactions with the Ni?Ni distances of 3.900, 4.198, and 4.165 Å. Magnetic susceptibility measurements for these complexes in the temperature range 1.8-300 K show that the overall magnetic behavior for 1 and 2 indicates the presence of antiferromagnetic interaction, but 1 exhibits an activated magnetic behavior in the high-temperature (HT) region together with a Curie tail in the low-temperature (LT) region. 相似文献
20.
Qian Huang Li-Bo Liang Hong-Rong Zuo Le-Min Yang Xue-Lei Hu 《Inorganica chimica acta》2010,363(11):2546-2552
Three new ion-pair complexes, [4RBzDMAP]2[Cu(mnt)2] (mnt2− = maleonitriledithiolate; [4RBzDMAP]+ = 1-(4′-R-benzyl)-4-dimethylaminopyridinium, R = F(1), Cl(2) and Br(3)) were synthesized and characterized by elemental analyses, IR, UV, single crystal X-ray diffraction and magnetic measurements. The [Cu(mnt)2]2− anions and the cations stack alternately and form a 1D column via C-H···S, C-H···π or C-H···Cu interactions for 1 and 2. While the cations stack into a column though π···π or C-H···π interactions between pyridine and phenyl rings for 1 and 3. The change of the molecular topology of the counteraction when the 4-substituted group in the benzyl ring have been changed from F or Cl to Br atom, results in the difference in the crystal system, space group and the stacking mode of the cations and anions of 1, 2 and 3. Some weak hydrogen bonds between the adjacent columns further generate a 3D network structure. It is interesting that 1 and 2 exhibits antiferromagnetic coupling with θ = −2.372 K and θ = −14.732 K, while 3 shows weak ferromagnetic coupling feature with θ = 0.381 K. 相似文献