Magnetic investigation of copper(II) diethyldithiocarbamate

Santen, J.A. van; Duyneveld́t, A.J. van; Carlin, Richard L.

doi:10.1021/ic50209a062

Cited by 14 publications

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“…In the first case [56] Curie-Weiss behavior was observed only above 11 K and the reported Weiss constant was + 2 K. In the case of the newer data [57] Curie-Weiss behavior was observed over practically the whole measured temperature interval, with deviations only beginning to appear at the lowest H (kOe) [54] 5. Introduction to Magnetic Exchange: Dimers and Clusters x 10-3 emu/(mol-Cu) at 4.20 K. The isothermal susceptibility as a function of applied field was also reported.…”

Section: Some Other Dimersmentioning

confidence: 76%

“…Several other susceptibility measurements were also reported [54], such as the ac susceptibility as a function of applied magnetic field and the high-frequency (adiabatic) susceptibility. All the data are consistent with the ferromagnetic intrapair interaction being of the order of only 1/k = 0.96 K, with an antiferromagnetic interpair interaction of 1'/k=-0.007K.…”

Section: Some Other Dimersmentioning

confidence: 99%

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Introduction to Magnetic Exchange: Dimers and Clusters

Carlin

1986

Magnetochemistry

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Energy Levels and Specific Heats 71configurational mixing of states such as M+ F M2+. The electron on Fin (c) and (d) can now couple with the lone electron in a d z 2 orbital on an adjoining Ni2+ . The preferred coupling is to give a singlet state [(c), called antiferromagnetic] rather than a triplet, (d). This in turn stabilizes the singlet state (a) with respect to the triplet (b). The strength of the interaction will depend on the amount of overlap, and we present here only a model of 180° superexchange. Metal ion orbitals can also overlap with p" ligand orbitals at a 90° angle, and much recent research effort has gone into finding the factors which influence this superexchange interaction.This model, which has been applied to a variety of systems [1,2] is somewhat similar to that which is used for explaining spin-spin coupling in NMR spectroscopy [3]. The Hamiltonian in use for metal-metal exchange interaction in magnetic insulators is of the form (5.2) where the sum is taken over all pair-wise interactions of spins i and j in a lattice. For the moment, we shall restrict our attention to dimers, and thereby limit the summation to the two atoms 1 and 2 in the dimeric molecule, so thatThis is called an isotropic (note the dot product between the two spins, S) or Heisenberg Hamiltonian, and we adopt the convention that negative J refers to antiferromagnetic (spin-paired or singlet ground state in a dimer) interactions, and positive J refers to ferromagnetic (spin-triplet ground state) interactions. The exchange constant J is given in energy units (Kelvins) and measures the strength ofthe interaction. The reader must be careful in comparing different authors, for a variety of conventions (involving the negative sign and even the factor of 2) are in use. (The symbol J now takes a different meaning from its earlier use as the quantum operator for total angular momentum.) Energy Levels and Specific HeatsAn antiferromagnetic interaction ofthe type given in Eq. (5.3), when applied to two ions each of!/ = t gives a spin-singlet ground state and a spin-triplet 2J in energy above the singlet ( Fig. 5.2). Naturally, ifthe interaction were ferromagnetic, the diagram is simply inverted. For an external field applied along the z-axis of the pair, the complete Hamiltonian will be taken as

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Section: Some Other Dimersmentioning

confidence: 76%

Section: Some Other Dimersmentioning

confidence: 99%

Introduction to Magnetic Exchange: Dimers and Clusters

Carlin

1986

Magnetochemistry

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“…Initial low temperature (4-2-56 K) magnetic susceptibility studies were interpreted by Villa and Hatfield [14] in terms of a ferromagnetic coupling between the copper(II) ions with 2J = + 24 cm-1 and their later investigations in the temperature range of 1.7-7.0 K revealed a lower value for 2J [39]. A reinvestigation of the magnetic behaviour of this by Carlin and co-workers [25(b)], however, revealed that this system behaves as a normal S = 89 paramagnet in the temperature range of 1-20K.…”

Section: Comlmrison Of Exchange Constantsmentioning

confidence: 99%

Triplet-state E.P.R. studies of exchange coupled copper(II) and silver(II) pairs in zinc(II) bis[N.N.-diisopropyldithiocarbamate]

Sreehari

Manoharan

1988

Molecular Physics

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Ambient temperature single crystal triplet-state E.P.R. studies on exchange coupled Cu2+-Cu2+ pairs in zinc(II) bis[N,N-diisopropyldithiocarbamate] matrix and temperature dependent E.P.R. studies on powder samples of Cu 2 § Cu 2+ and Ag2+-Ag 2+ pairs, separated by a distance of 3.545 A, in the same host lattice are reported. In addition to the doublet spectra, we observed the triplet lines arising due to spin-spin interactions. The directions of g and Dtensors in Cu 2 +-Cu 2 § pairs vary by 42 ~ in the xz-plane. The D-tensor seems to receive its contribution both from the dipolar and pseudo-dipolar interactions. The zero-field splitting (Z.F.S.) tensor, 'D', increases linearly with decrease in temperature down to 80K. This effect is seen in both Cu2+--Cu 2+ and Ag 2 § Ag 2 § pairs: it is tentatively attributed to a crystal contraction at low temperatures. The integrated intensities of AMs = + 2 E.P.R. transitions of the triplets have been used to estimate the magnitude and sign of isotropic exchange coupling constants (2,/). The values of 23 for Cu 2 +~Cu 2 +and Ag 2 +-Ag e+ pairs are found to be 40.2cm-x and 62.5 cm-1, respectively. The interaction in both the systems has been found to be 'ferromagnetic '.

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Electro‐ and Magnetocommunication in [5,5]Ditrovacenyls, [(η⁷‐C₇H₇)V(η⁵‐C₅H₄‐X‐η⁵‐C₅H₄)V(η⁷‐C₇H₇)], Mediated by the Spacers X=(Z)CHCH, (E)CHCH, >CCH₂, CH₂CH₂, and CH₂

Elschenbroich

Plackmeyer

Nowotny

et al. 2005

Chemistry A European J

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Five new paramagnetic dinuclear complexes containing [5]trovacenyl groups, (eta7-C7H7)V(eta5-C5H4-), have been prepared and characterized, including by single-crystal X-ray diffraction. As intervening spacers, ethenediyl units in the geminal and vicinal (Z)- and (E)-bridging modes as well as methanediyl and ethanediyl units have been included with the aim of studying their propensity to transmit electric and magnetic information. It is found that redox splitting of consecutive electron-transfer steps is resolved for reduction (0-->1- -->2-) only, unsaturation of the C2 bridge not being requisite, since the -CH2CH2- spacer also gives rise to a small redox splitting. Magnetic communication is quantified in terms of the exchange coupling constant J, accessible from the EPR hyperfine pattern in solution and from magnetic susceptometry in the solid state. The results obtained from these methods generally differ; this fact is not surprising in view of conformational differences in the respective states of aggregation. It is concluded that orientation-dependent mechanisms of spin-spin interactions (pi-orbital overlap, hyperconjugation) contribute extensively although, as implied by sizeable J values for -CH2- and -C2H4- linked di[5]trovacenyl groups, coupling mediated by the sigma-orbital chain must also be considered.

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Magnetic investigation of copper(II) diethyldithiocarbamate

Cited by 14 publications

References 1 publication

Introduction to Magnetic Exchange: Dimers and Clusters

Introduction to Magnetic Exchange: Dimers and Clusters

Triplet-state E.P.R. studies of exchange coupled copper(II) and silver(II) pairs in zinc(II) bis[N.N.-diisopropyldithiocarbamate]

Electro‐ and Magnetocommunication in [5,5]Ditrovacenyls, [(η⁷‐C₇H₇)V(η⁵‐C₅H₄‐X‐η⁵‐C₅H₄)V(η⁷‐C₇H₇)], Mediated by the Spacers X=(Z)CHCH, (E)CHCH, >CCH₂, CH₂CH₂, and CH₂

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Magnetic investigation of copper(II) diethyldithiocarbamate

Cited by 14 publications

References 1 publication

Introduction to Magnetic Exchange: Dimers and Clusters

Introduction to Magnetic Exchange: Dimers and Clusters

Triplet-state E.P.R. studies of exchange coupled copper(II) and silver(II) pairs in zinc(II) bis[N.N.-diisopropyldithiocarbamate]

Electro‐ and Magnetocommunication in [5,5]Ditrovacenyls, [(η7‐C7H7)V(η5‐C5H4‐X‐η5‐C5H4)V(η7‐C7H7)], Mediated by the Spacers X=(Z)CHCH, (E)CHCH, >CCH2, CH2CH2, and CH2

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Electro‐ and Magnetocommunication in [5,5]Ditrovacenyls, [(η⁷‐C₇H₇)V(η⁵‐C₅H₄‐X‐η⁵‐C₅H₄)V(η⁷‐C₇H₇)], Mediated by the Spacers X=(Z)CHCH, (E)CHCH, >CCH₂, CH₂CH₂, and CH₂