Calculation of the Antiferromagnetic Coupling and the Absorption Spectra of the Cation mu-Oxobis {pentaamminechromium(III)} by Means of Symmetry Parameters.

Glerup, Jørgen; Woldbye, Flemming; Tucker, Edwin E.; Songstad, Jon; Pilotti, Åke

doi:10.3891/acta.chem.scand.26-3775

Cited by 60 publications

(35 citation statements)

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“…The mechanisms and parameters that govern the exchange interaction are qualitatively quite well understood. Thus, angular overlap model (AOM) considerations have been relatively successful in rationalising the magnetic properties of this class of systems,2,11 but these models have some shortcomings that lead to systematic errors (see below). These models are furthermore semiempirical to a more pronounced degree than the underlying AOM by encompassing additional parameters, which are fixed by fits to experimental data.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterisation and Modelling of a Ferromagnetically Coupled Chromium(III) Dimer: Di‐μ‐hydroxobis[tetrakis(isothiocyanato)chromate(III)]

2014

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A rare example of a ferromagnetically coupled dinuclear chromium(III) complex, the di-μ-hydroxobis[tetrakis(isothiocyanato)chromate(III)] anion, is reported. This complex has been synthesised from the oxo-bridged acetonitrile complex [(CH 3 CN) 5 CrOCr(NCCH 3 ) 5 ](BF 4 ) 4 and isolated as the solvated tetraphenylphosphonium salt, (Ph 4 P) 4 [(SCN) 4 -Cr(OH) 2 Cr(NCS) 4 ]·2CH 3 CN (1). From magnetometry the coupling constant, J, was determined to be -5.17 cm -1 (in an H = JS A ·S B scheme). The X-band EPR spectra were measured in the temperature range 2-305 K and the data were modelled. The spectra, which are very rich, are the first re-[a]

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Section: Introductionmentioning

confidence: 99%

Synthesis, Characterisation and Modelling of a Ferromagnetically Coupled Chromium(III) Dimer: Di‐μ‐hydroxobis[tetrakis(isothiocyanato)chromate(III)]

2014

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“…(15) and (16) are fitted to the J exp values in Tables 1 and 2, with e pp ¢ and e ps ¢ as adjustable parameters, and K av ¢=0. 25. The parameter values obtained are e¢ pp = 22.4 cm -1/2 and e¢ ps = 47 cm -1/2 .…”

Section: Resultsmentioning

confidence: 99%

“…The parameters h hh and h hq =h qh depend on j and h xx does not. They can be expressed in angular overlap model (AOM) parameters as follows [25,26].…”

Section: Model Parametersmentioning

confidence: 99%

Average One-Center Two-Electron Exchange Integrals and Exchange Interactions

Mossin

Weihe

2004

Structure and Bonding

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We show how the introduction of the average one-center two-electron exchange integral, which is closely related to Jørgensens spin-pairing energy parameter, facilitates comparison of the Heisenberg-Dirac-van Vleck exchange parameter for different transition metal dimers. The formalism is illustrated on m-oxo-dimanganese(III) and m-oxo-dichromium(III) complexes in which the oxo bridge is the important exchange pathway.

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“…The oxo-bridged chromium complexes have also been the subject of several experimental [26] and theoretical [27,28] investigations. Although the ground= state manifold can sometimes be considered as reduced to one singlet, even at room temperature, the R lines frequently show a poorly resolved structure and this renders difficult the estimation of exchange interaction in the corresponding excited state.…”

Section: Introductionmentioning

confidence: 99%

Exchange interactions in polynuclear complexes

et al. 1977

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We present detailed optical and magneto-optical data on CsaCr~CI9 as a single crystal containing only pairs of Cr 3+ ions. Measurements have been carried out in a wide range of temperatures down to pumped helium and in the whole spectral region covering all singly and several doubly excited states. MCD helped considerably in resolving the absorption spectra into their numerous components, and proved especially useful in demonstrating the occurrence of a double excitation to 4T 2. It provides also parallel g factors for several excited terms.The main conclusions of our work are: (i) all transitions are electric dipole allowed ; (ii) transitions to singly excited doublet states are essentially promoted via a single ion mechanism; (iii) vibronic interaction must be invoked to understand the absorption data on sharp lines ; (iv) the trigonal plus spin-orbit interaction competes favourably with exchange interaction to produce excited states splittings.We present also a new non-phenomenological model to describe the splitting of the 4A 2@2E manifold under the combined effects of exchange, trigonal and spin-orbit interaction. This model includes no adjustable parameter. It leads to A0~180 cm -1 and offers a good starting basis for a coherent interpretation of most of our experimental data.

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Calculation of the Antiferromagnetic Coupling and the Absorption Spectra of the Cation mu-Oxobis {pentaamminechromium(III)} by Means of Symmetry Parameters.

Cited by 60 publications

References 0 publications

Synthesis, Characterisation and Modelling of a Ferromagnetically Coupled Chromium(III) Dimer: Di‐μ‐hydroxobis[tetrakis(isothiocyanato)chromate(III)]

Synthesis, Characterisation and Modelling of a Ferromagnetically Coupled Chromium(III) Dimer: Di‐μ‐hydroxobis[tetrakis(isothiocyanato)chromate(III)]

Average One-Center Two-Electron Exchange Integrals and Exchange Interactions

Exchange interactions in polynuclear complexes

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