Thiosemicarbazone complexes of copper(II): structural and biological studies

Factors affecting the magnetic properties of dimeric copper(II) complexes

We have structurally and magnetically characterized a total of 12 complexes based on the Single-Molecule Magnet (SMM) [MnIII6O2(sao)6(O2CH)2(MeOH) 4] (1) (where sao2- is the dianion of salicylaldoxime or 2-hydroxybenzaldeyhyde oxime) that display analogous structural cores but remarkably different magnetic behaviors. Via the use of derivatized oxime ligands and bulky carboxylates we show that it is possible to deliberately increase the value of the spin ground state of the complexes [Mn6O2(Me-sao)6(O2CCPh3)2(EtOH)4] (2), [Mn6O2(Et-sao)6(O2CCMe3)2(EtOH)5] (3), [Mn6O2(Et-sao)6(O2CPh2OPh)2(EtOH)4] (4), [Mn6O2(Et-sao)6(O2CPh4OPh)2(EtOH)4(H2O)2] (5), [Mn6O2(Me-sao)6(O2CPhBr)2(EtOH)6] (6), [Mn6O2(Et-sao)6(O2CPh)2(EtOH)4(H2O)2] (7), [Mn6O2(Et-sao)6{O2CPh(Me)2}2(EtOH)6] (8), [Mn6O2(Et-sao)6(O2C11H15)2(EtOH)6] (9), [Mn6O2(Me-sao)6(O2C-th)2(EtOH)4(H2O)2] (10), [Mn6O2(Et-sao)6(O2CPhMe)2(EtOH)4(H2O)2] (11), and [Mn6O2(Et-sao)6(O2C12H17)2(EtOH)4(H2O)2] (12) (Et-saoH2 = 2-hydroxypropiophenone oxime, Me-saoH2 = 2-hydrox...

Toward a Magnetostructural Correlation for a Family of Mn6 SMMs

Three isomorphous compounds M(CHOO)3[NH2(CH3)2] (M = Mn(1·Mn), Co(2·Co), Ni(3·Ni)) have been synthesized in solvothermal conditions. Single-crystal X-ray diffraction shows that they are all crystallized in the trigonal space group R 3c with small differences in the lattice parameters. Bridged by the three-atom single-bridge CHOO-, M ions form a three-dimensional distorted perovskite-like structure with dimethylamine (DMA) cations located in the cages of the network. Based on the magnetic data, these three 3D compounds are weak ferromagnets with the critical temperature Tc = 8.5 K (1·Mn), 14.9 K (2·Co), and 35.6 K (3·Ni), and for 2·Co and 3·Ni, spin reorientation might take place at 13.1 and 14.3 K, respectively. At 1.8 K, hysteresis loops can be observed for all three compounds with the coercivity field ca. 90 Oe (1·Mn), 920 Oe (2·Co), and 320 Oe (3·Ni). The canting angles are estimated to be 0.08°, 0.5°, and 0.6° for 1·Mn, 2·Co, and 3·Ni, respectively. The magnetic coupling between MnII ions in 1·Mn was...

Perovskite-like Metal Formates with Weak Ferromagnetism and as Precursors to Amorphous Materials

Plasticity of the coordination sphere of copper(II) complexes, its manifestation and causes

Les structures de six dimeres de benzoate de cuivre(II) ont ete determinees. Les valeurs de -2J obtenues a partir des mesures de susceptibilite magnetique sont situees dans la gamme 316-350cm -1 . La petite interaction ferromagnetique anormale de l'additif quinoleine , -2J=267cm -1 , serait due a la structure courbee des ponts Cu-O-C-O-Cu, possedant un angle de courbure moyen de 11.4°

Magneto-structural correlation in dimeric copper(II) benzoates

L'etude structurale des complexes du cuivre montre qu'il n'y a pas de difference geometrique importante dans les cages Cu 2 (COO) 4 entre les cuivre acetate et cuivre formiate. Les populations electroniques des groupes carboxylate des coordinats pontants sont correlees avec les valeurs −25 des carboxylate des complexes de Cu(II). le point-cle de la force de l'interaction d'echange de spins reside dans la population de l'orbitale 2p x de l'atome C du carboxylate

Correlation of electron density and spin-exchange interaction in dimeric copper(II) formates, acetates and silanecarboxylates

The reaction of cupric acetate with the reaction mixture of γ-aminopropyl alcohol and substituted salicylaldehydes in ethanol gave dimeric copper(II) complexes. The postulated structure of these complexes makes it possible to test the substituent effect transmitted to the coordinating atoms which are not in the superexchange pathway between copper-(II) ions in a pair. The magnetic moments observed at room temperature were corrected for the temperature variations to those at 25°C by graphic method based on Bleaney and Bowers’ equation. The observed substituent effect on the relation between μeff25°C and λmax is different from that observed for dimeric cupric halides complexes of substituted pyridine N-oxides. In these complexes the substituent effect transmits to the bridging oxygen atom in the superexchange pathway. As compared with the parent complex (H), methyl, chloro and benzo groups weakened the magnetic interaction but nitro group strengthened it. An interpretation of the substituent effect is given...

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Magnetic Moments and d–d Bands of N-n-Propanolsalicylaldiminato-copper(II)

Determination de seize structures cristallines des trichloroacetates de cuivre II dimeriques. Dans les cristaux dans lesquels la valeur de -2J est petite (inferieure a 200cm -1 ), la geometrie de coordination autour de l'atome Cu est deformee d'une pyramide carree (SP) vers une bipyramide rhomboedrique (TBP) et la distance interatomique Cu...Cu est allongee. Plus la distance Cu...Cu est grande, plus la valeur -2J est petite, indiquant que l'interaction de superechange entre spins est plus faible dans la structure TBP que dans la structure SP

Michinobu Kato

Papers

Factors affecting the magnetic properties of dimeric copper(II) complexes

Magneto-structural correlation in dimeric copper(II) benzoates

Correlation of electron density and spin-exchange interaction in dimeric copper(II) formates, acetates and silanecarboxylates

Magnetic Moments and d–d Bands of N-n-Propanolsalicylaldiminato-copper(II)

Magneto-structural corrections of dimeric copper(II) trichloroacetates