Magnetic susceptibility and optical study of the organic-intercalated two-dimensional ionic ferromagnet bis(benzylammonium) tetrachlorochromate(II)

Bellitto, Carlo; Day, Peter; Wood, T. E.

doi:10.1039/dt9860000847

Cited by 31 publications

(21 citation statements)

References 2 publications

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“…The 2−300 K temperature dependencies of the magnetic susceptibility of 1 and 2 were fit by the Curie−Weiss expression, χ ∝ ( T − θ) -1 , with Landé g values of 2.39 and 2.00 and θ values of −154 and −16 K for T > 50 K, respectively, indicative of moderate to very strong antiferromagnetic coupling between metal sites, Figure . The 2.39 g value is in the range of values reported for Cr II [C(CN) 3 ] 2 5b and [H 3 N(CH 2 Ph)] 2 CrCl 4 . The room-temperature effective moments, μ eff [≡(8χ T ) 1/2 ], of 1 and 2 are 4.79, and 5.79 μ B , respectively.…”

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confidence: 57%

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Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

et al. 1999

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confidence: 57%

“…The 2.39 g value is in the range of values reported for Cr II [C(CN) 3 ] 2 5b and [H 3 N(CH 2 Ph)] 2 CrCl 4 . 8 The room-temperature effective moments, µ eff [≡(8χT) 1/2 ], of 1 and 2 are 4.79, and 5.79 µ B , respectively. These values are reduced from their † University of Utah.…”

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confidence: 99%

Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

et al. 1999

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“…A number of investigations 6,[11][12][13][14][15][16][17][18][19][20] on electronic spectra of multi-spin exchange coupled systems of transition metal complexes having binuclear structures or containing radical ligands have been published. Strongly spin-coupled Cr(III) semiquinone or phenoxy radical complexes 19,20 have demonstrated large intensity enhancement of the spin forbidden d-d transitions arising from strong antiferromagnetic interactions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Magnetic Properties, and Electronic Spectra of Octahedral Mixed-Ligand (β-Diketonato)nickel(II) Complexes with a Chelated Nitronyl Nitroxide Radical

et al. 1999

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Two series of new mixed-ligand nitronyl nitroxide Ni(II) complexes of [Ni(beta-diketonato)(2)(NIT2-py)] and [Ni(beta-diketonato)(tmen)(NIT2-py)](+) types with various kinds of beta-diketonates have been synthesized and structurally and magnetically characterized, where NIT2-py is 2-(2-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxyl 3-oxide and tmen is N,N,N ',N '-tetramethylethylenediamine. The X-ray structural analysis for three tmen complexes with 2,4-pentanedionate (1b), 1,3-diphenyl-1,3-propanedionate (2b), and 4,4,4-trifluoro-1-phenyl-1,3-butanedionate (5b) demonstrated that the beta-diketonato complexes assume a mer (cis,trans) N(3)O(3) geometrical configuration. The structural parameters are as follows: 1b (C(23)H(39)F(6)N(5)NiPO(4).(1)/(3)CH(2)Cl(2)), trigonal, R&thremacr;, a = 33.299(5) Å, c = 15.007(9) Å, Z = 18; 2b (C(28)H(41)F(6)N(5)NiPO(4)), orthorhombic, Pbca, a = 23.732(6) Å, b = 18.504(5) Å, c = 15.345(4) Å, Z = 8; 5b (C(28)H(38)F(9)N(5)NiPO(4)), triclinic, P&onemacr;, a = 12.068(2) Å, b = 16.942(2) Å, c = 9.161(1) Å, alpha = 105.26(1) degrees, beta = 103.72(1) degrees, gamma = 71.62(1) degrees, Z = 2. The antiferromagnetic interactions between Ni(II) and NIT2-py were found within ranges of J = -207 to -224 cm(-)(1) for the bis(beta-diketonato) complexes and of J = -35 to -150 cm(-)(1) for the (beta-diketonato)(tmen) complexes. The displacement of the beta-diketonates with tmen in bis(beta-diketonato) complexes decreases the J values, and the effect of the 1,3-substituents in the beta-diketonates on the J values is observed in a systematic manner for all the bis(beta-diketonato) complexes and for the (methyl- and phenyl-substituted-beta-diketonato)(tmen) complexes but not for the trifluoromethyl-substituted complex. The room-temperature electronic spectra of the bis(beta-diketonato) and the (beta-diketonato)(tmen) complexes exhibit enhanced spin-forbidden d-d transitions at 13.0 x 10(3) cm(-)(1) and new metal-ligand charge-transfer (MLCT) transitions around (16.0-19.0) x 10(3) cm(-)(1). The variation of the spectroscopic characteristics with modification of the beta-diketonato ligands is discussed through the exchange mechanism in connection with the antiferromagnetic interactions in terms of the substituent effects or the Hammett sigma(m) constants.

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“…However, until now, very few studies have been devoted to the optical properties of molecular-based magnets, in relation with their magnetic properties. [12][13][14] Of course, a great deal of effort has already concerned the spectroscopy of exchange-coupled systems, but essentially in doped compounds. 15 Along this line, the Mn II Cu II molecular compounds are interesting not only for their magnetic properties but also for their spectroscopic properties.…”

Section: Introductionmentioning

confidence: 99%

“…Promising opportunities could emerge for these materials in magneto-optical devices. However, until now, very few studies have been devoted to the optical properties of molecular-based magnets, in relation with their magnetic properties. − Of course, a great deal of effort has already concerned the spectroscopy of exchange-coupled systems, but essentially in doped compounds …”

Section: Introductionmentioning

confidence: 99%

Optical Absorption Spectroscopy of the Tetranuclear Compound [Mn{Cu(oxpn)}₃](ClO₄)₂·2H₂O (oxpn = N,N‘-Bis(3-aminopropyl)oxamide): Complementarity with Magnetic Properties

1997

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The optical absorption spectroscopy of the tetranuclear compound [Mn{Cu(oxpn)}(3)](ClO(4))(2).2H(2)O, with oxpn standing for N,N'-bis(3-aminopropyl)oxamide, has been investigated in the 4-300 K temperature range. The central Mn(II) ion is linked to three Cu(oxpn) complex ligands, so the molecular symmetry may be defined as D(3). The spectra, in addition to a d-d transition at 19 230 cm(-)(1) due to the Cu(II) ion in square planar surroundings, exhibit narrow and intense Mn(II) spin-forbidden transitions in the 24 300-28 750 cm(-)(1) range. These transitions are activated by an exchange mechanism. The temperature dependence of the main feature corresponding to the (6)A(1) --> (4)A(1),(4)E(G) Mn(II) transition was investigated. Using a model proposed first by Tanabe and co-workers and adapted to the MnCu(3) topology, a theoretical expression for the temperature dependence of the intensity of the transition has been established and compared with the experimental data. The only parameter of this expression is the interaction parameter J between the local ground states (H = -J summation operator(i)()S(Mn)()i.S(Cu)()i), which has been found to be -33.8 cm(-)(1). The energy of the transition has been found to be shifted by 47 cm(-)(1) toward the high energies as the temperature was lowered. A theoretical expression for the energy shift of the transition has been given. It depends on both J and the interaction parameter J between the Cu(II) ions in their ground states and the Mn(II) ion in the spin flip excited state. The comparison with the experimental data has led to a negative J value of the same order of magnitude as the J value. These results have been discussed in relation with the information deduced from magnetic measurements.

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Magnetic susceptibility and optical study of the organic-intercalated two-dimensional ionic ferromagnet bis(benzylammonium) tetrachlorochromate(II)

Cited by 31 publications

References 2 publications

Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

Synthesis, Magnetic Properties, and Electronic Spectra of Octahedral Mixed-Ligand (β-Diketonato)nickel(II) Complexes with a Chelated Nitronyl Nitroxide Radical

Optical Absorption Spectroscopy of the Tetranuclear Compound [Mn{Cu(oxpn)}₃](ClO₄)₂·2H₂O (oxpn = N,N‘-Bis(3-aminopropyl)oxamide): Complementarity with Magnetic Properties

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Magnetic susceptibility and optical study of the organic-intercalated two-dimensional ionic ferromagnet bis(benzylammonium) tetrachlorochromate(II)

Cited by 31 publications

References 2 publications

Spontaneous Magnetization in the M[N(CN)2]2 (M = Cr, Mn) Weak Ferromagnets

Spontaneous Magnetization in the M[N(CN)2]2 (M = Cr, Mn) Weak Ferromagnets

Synthesis, Magnetic Properties, and Electronic Spectra of Octahedral Mixed-Ligand (β-Diketonato)nickel(II) Complexes with a Chelated Nitronyl Nitroxide Radical

Optical Absorption Spectroscopy of the Tetranuclear Compound [Mn{Cu(oxpn)}3](ClO4)2·2H2O (oxpn = N,N‘-Bis(3-aminopropyl)oxamide): Complementarity with Magnetic Properties

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Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

Spontaneous Magnetization in the M[N(CN)₂]₂ (M = Cr, Mn) Weak Ferromagnets

Optical Absorption Spectroscopy of the Tetranuclear Compound [Mn{Cu(oxpn)}₃](ClO₄)₂·2H₂O (oxpn = N,N‘-Bis(3-aminopropyl)oxamide): Complementarity with Magnetic Properties