Structure and magnetism of bis(propionato)-p-toluidinecopper(II), a cupric carboxylate adduct with a one-dimensional polymeric structure

Yawney, D. B. W.; Moreland, James A.; Doedens, Robert J.

doi:10.1021/ja00785a028

Cited by 43 publications

(7 citation statements)

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“…A more complete set of measurements is required before one can be satisfied that this system is well-understood. Furthermore [30], the p-toluidine adduct of copper(II) propionate, which is composed of onedimensional polymeric chains, exhibits a magnetic susceptibility (over a limited range of temperatures) which fits the Bleaney-Bowers scheme quite well.…”

Section: +E(s;-s;)mentioning

confidence: 79%

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: +E(s;-s;)mentioning

confidence: 79%

Introduction to Magnetic Exchange: Dimers and Clusters

Carlin

1986

Magnetochemistry

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“…The origin of band II remains unclear but has been assigned to a charge-transfer absorption . Band II is believed to be indicative of a dimeric complex ,, even though a number of monomeric and polymeric Cu(II) compounds exhibit this band. ,, All of the complexes, however, display bands I and II in the usual range for Cu(II) compounds in a square-pyramidal CuO 4 O environment. , None of the solid state spectra display a carboxy−copper(II) charge-transfer absorption in the 240−280-nm range (band III), because IndoH has a strong absorption in the 200−400-nm range. Consequently, band II of the Cu complexes partially overlaps with this band and band III is concealed.…”

Section: Resultsmentioning

confidence: 99%

Anti-Inflammatory Dinuclear Copper(II) Complexes with Indomethacin. Synthesis, Magnetism and EPR Spectroscopy. Crystal Structure of the N,N-Dimethylformamide Adduct

et al. 1999

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Veterinary anti-inflammatory Cu(II) complexes of indomethacin (1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid = IndoH), of the general formula [Cu(2)(Indo)(4)L(2)] (L = N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), and water), were studied by zero-field and X-band EPR spectroscopies, electronic spectroscopy, magnetic measurements, and X-ray powder diffraction. The complexes are similar to Cu(II) acetate monohydrate, with a strong antiferromagnetic exchange interaction, J, ranging from -141 to -152 cm(-)(1). Variable temperature magnetic susceptibility data for all of the complexes are similar, with the exception of a [Cu(2)(Indo)(4)(H(2)O)(2)] complex, which displays an unusual increase in magnetic moment with decreasing temperature from 50 to 10 K. The X-ray powder diffraction patterns of the DMF and DMA dimers show that they are isostructural. Two isostructural H(2)O complexes were synthesized from different methods yet displayed different variable temperature magnetic susceptibity data. All of the [Cu(2)(Indo)(4)L(2)] complexes crystallize in the triclinic space group P&onemacr;. Single-crystal X-ray diffraction analysis of the DMF complex, [Cu(2)(Indo)(4)(DMF)(2)].1.6(DMF), shows that it is similar to the previously reported [Cu(2)(Indo)(4)(DMSO)(2)] with a Cu-Cu bond length of 2.630(1) Å, Cu-O(RCOO) of 1.960(4)-1.967(4) Å, and Cu-O(DMF) of 2.143(5) Å and crystal parameters a = 10.848(3) Å, b = 13.336(6) Å, c = 16.457(4) Å, alpha = 104.67(3) degrees, beta = 100.94(2) degrees, and gamma = 107.16(3) degrees. The X-ray structure of the DMF dimer does not exhibit strong intermolecular interactions due to the hydrophobic nature of the exterior. This may be important in facilitating its dissolution in micelles and transport through membranes.

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“…A magnetic study of copper(I1) propionate .p-toluidine (70) shows that its susceptibility versus T curve can be satisfactorily fitted to Eq. 1 and that it is magnetically representative of the acetate and butyrate adducts of anilinetype bases studied by Kokot and Martin.…”

Section: Amine Adducts Of Copper@) Carboxylatesmentioning

confidence: 99%

“…Because there appeared to be no obvious explanation for this magnetic behavior, we set out to determine the structure of a copper(I1) carboxylate adduct of aniline or a related base. Many of these adducts proved to be unstable or poorly crystalline; however, suitable crystals of the p-toluidine adduct of copper(I1) propionate could be obtained under anhydrous conditions and were subjected to a crystal structure analysis (70).…”

Section: Amine Adducts Of Copper@) Carboxylatesmentioning

confidence: 99%