Search

Thermal-assisted spin crossover and field-induced slow magnetic relaxation coexist in the solid state for the mononuclear cobalt(II) complex with the non-innocent 2,6-bis(N-4-methoxyphenylformimidoyl)pyridine ligand. One-electron oxidation of the paramagnetic low-spin CoII ion (SCo = 1/2) to the diamagnetic low-spin CoIII ion (SCo = 0) leads to the electroswitching of the slow magnetic relaxation in acetonitrile solution.

The Cu(2+)-mediated self-assembly of oxamato-based ligands derived from either the (S)- or (R)-enantiomers of the amino acid valine leads to the formation of two antiferromagnetically coupled homochiral anionic hexacopper(II) wheels in the presence of templating tetramethylammonium countercations.

From DFT and time-dependent DFT calculations on MnIISOD and FeIISOD active site models interacting with O2− we have determined that metal-to-ligand charge transfers stabilise the S = 2 and S = 5/2 spin states as ground spin states for the [MnIISOD-O2−] and [FeIISOD-O2−] model complexes, respectively. These charge transfers are ruled by the electronic configuration of the metal ion, and they can be determinant in the catalysis reaction.

A unique magnetic electroswitching behavior has been observed in an oxamato-based permethylated dicopper(II) paracyclophane; upon reversible one-electron oxidation of the double tetramethyl-substituted p-phenylenediamidate bridging skeleton, the spin alignment of the two Cu(II) ions (S(Cu) = ½) changes from antiparallel (OFF) to parallel (ON) in the resulting dicopper(II) π-radical cation species.

The coordination chemistry of the 2,3-quinoxalinediolate ligand with different lanthanide(iii) ions in basic media in air affords a new family of carbonato-bridged M 2 III compounds (M = Pr, Gd and Dy), the Dy 2 III analogue exhibiting slow magnetic relaxation behaviour typical of single-molecule magnets. This journal is © 2012 The Royal Society of Chemistry., This work was supported by the MICINN (Spain) (Projects CTQ2010-15364 and CSD2007-00010), the Generalitat Valenciana (Spain) (Projects PROMETEO/2009/108 and ISIC/2012/002) and the ESRF (France) (Projects HS3902 and 25-01-783).

Thermally reversible photomagnetic (ON/OFF) switching behavior has been observed in a dinuclear oxamatocopper(ii) anthracenophane upon UV light irradiation and heating; the two CuII ions (SCu = 1/2) that are antiferromagnetically coupled in the dicopper(ii) metallacyclic precursor (ON state) become uncoupled in the corresponding [4+4] photocycloaddition product (OFF state), as substantiated from both experimental and theoretical studies. © 2011 The Royal Society of Chemistry., This work was supported by the MICINN (Spain) (Projects CTQ2010-15364, MAT2010-16981, CSD2007-00010, CSD2006-00015, and DPI2010-21103-C04-03), the Generalitat Valenciana (Spain) (Project PROMETEO/2009/108), the ACIISI-Gobierno Autónomo de Canarias (Spain) (Project PIL-2070901), and the ESRF (France) (Project HS3902). M. C. and J. F.-S. thank the MICINN and the Generalitat Valenciana, respectively, for doctoral grants. E. P. and J. P. thank the MICINN (Project ‘‘Juan de la Cierva’’) and the ACIISI-Gobierno Autónomo de Canarias (Project NANOMAC), respectively, for postdoctoral contracts.

A novel one-dimensional copper(II) compound [Cu(L)(μ1,3-N3)(ClO4)]n [L = tridentate Schiff base, formed by condensation of pyridine-2-aldehyde and 1-(2-aminoethyl)piperidine] has been synthesized and structurally characterized; it exhibits ferromagnetic interaction via end-to-end azido (μ1,3-N3) linkages, as rationalised by DFT calculation.

Reacting hexacyanochromate(III) with a mononuclear Ni(II) complex chelated by two bidentate organic radicals leads to a pentanuclear complex with three different kinds of paramagnetic species interacting ferromagnetically and stabilising a high spin S = 9 ground state.

A novel octanuclear hydroxonickel(II) complex possessing a unprecedented cube molecular structure with eight Ni(II) ions at each vertex, six micro4-OH- groups closing each face and twelve exo-bidentate pyrazolate ligands (micro2-pz) spanning each edge, has been synthesized and its magnetic properties investigated.

Density functional theory (DFT) calculations and Monte Carlo (MC) simulations are used to calculate the exchange interactions in the Fe(III) cluster [Fe14(bta)6O6(OMe)18Cl6], impossible to determine by conventional methods – the results support a huge ground state spin arising from competing antiferromagnetic interactions.