Magnetocaloric efficiency tuning through solvent-triggered 3D to 2D interconversion in holmium(III)-based dynamic MOFs.

The neutral holmium(III) oxalate octadecahydrate {[Ho(ox)(HO)]·12HO} of mixed hexagonal/decagonal (6·10) 3D net topology shows important changes in the magnetocaloric efficiency upon dehydration/rehydration by heating and water vapor exposition to give the holmium(III) oxalate decahydrate {[Ho(ox)(HO)]·4HO} of hexagonal (6) 2D net topology through the intermediacy of the elusive amorphous anhydrous compound {Ho(ox)}.

Enantiomeric Complexes Based on Ruthenium(III) and 2,2'-Biimidazole: X-ray Structure and Magnetic Properties.

We have prepared and characterized two Ru(III) compounds based on the 2,2'-biimidazole (Hbiim) ligand, namely, a single complex of formula cis-[RuCl(Hbiim)]Cl·4HO () and a racemic mixture of formula {cis-[RuCl(Hbiim)]Cl}·4HO (), which contains 50% of Ru(III) complex . Both compounds crystallize in the monoclinic system with space groups 2 and 2 for and , respectively. These complexes exhibit the metal ion bonded to four nitrogen atoms from two Hbiim molecules and two chloride ions, which balance part of the positive charges in a distorted octahedral geometry.

pH-Switching of the luminescent, redox, and magnetic properties in a spin crossover cobalt(ii) molecular nanomagnet.

The ability of mononuclear first-row transition metal complexes as dynamic molecular systems to perform selective functions under the control of an external stimulus that appropriately tunes their properties may greatly impact several domains of molecular nanoscience and nanotechnology. This study focuses on two mononuclear octahedral cobalt(ii) complexes of formula {[Co(HL)][Co(HL)L]}(ClO)·9HO (1) and [CoL]·5HO (2) [HL = 4'-(4-carboxyphenyl)-2,2':6',2''-terpyridine], isolated as a mixed protonated/hemiprotonated cationic salt or a deprotonated neutral species. This pair of pH isomers constitutes a remarkable example of a dynamic molecular system exhibiting reversible changes in luminescence, redox, and magnetic (spin crossover and spin dynamics) properties as a result of ligand deprotonation, either in solution or solid state.

Lipoic Acid-Functionalized Hexanuclear Manganese(III) Nanomagnets Suitable for Surface Grafting.

Highly anisotropic single-molecule magnets (SMMs) have attracted much interest in the field of molecular magnetism because of their spin features and potential technological applications. Additionally, a great effort has been devoted to the functionalization of such molecule-based systems which are made with ligands containing functional groups suitable to connect SMMs to junction devices or to perform their grafting on surfaces of different substrates. We have synthesized and characterized two lipoic acid-functionalized and oxime-based Mn(III) compounds, of formula [Mn(μ-O)(HN-sao)(lip)(MeOH)][Mn(μ-O)(HN-sao)(cnph)(MeOH)]}·10MeOH () and [Mn(μ-O)(HN-sao)(lip)(EtOH)]·EtOH·2HO () [HN-saoH = salicylamidoxime, lip = lipoate anion, cnph = 2-cyanophenolate anion].

Trinuclear Cobalt(II) Triple Helicate with a Multidentate Bithiazolebis(oxamate) Ligand as a Supramolecular Nanomagnet.

The cobalt(II)-mediated self-assembly of the potentially tris(chelating) ,'-2,2'-(4,4'-bithiazole)bis(oxamate) (dabtzox) ligand gives a new metal-organic supramolecular nanomagnet of formula KCo(dabtzox)·8HO·MeOH () featuring a unique linear triple-stranded trinuclear structure of the helicate type.