The Missing Link in the Magnetism of Hybrid Cobalt Layered Hydroxides: The Odd–Even Effect of the Organic Spacer

OESTREICHER, VÍCTOR; BOROVIK, PAULA; CORONADO, EUGENIO; DOLLE, CHRISTIAN; ABELLÁN, GONZALO; DOLLE, CHRISTIAN; ABELLÁN, GONZALO; HUNT, DIEGO; JOBBÁGY, MATÍAS; HUNT, DIEGO; JOBBÁGY, MATÍAS; OESTREICHER, VÍCTOR; BOROVIK, PAULA; CORONADO, EUGENIO

CHEMISTRY-A EUROPEAN JOURNAL

WILEY-V C H VERLAG GMBH

Año: 2020

0947-6539

: A dramatic change in the magnetic behaviour,which solely depends on the parity of the organic linkermolecules, has been found in a family of layered CoII hydroxides covalently functionalized with dicarboxylic molecules. These layered hybrid materials have been synthesized at room temperature using a one-pot procedurethrough the epoxide route. While hybrids connected byodd alkyl chains exhibit coercive fields (Hc) below ca.3500 Oe and show spontaneous magnetization at temperatures (TM) below 20 K, hybrids functionalized with even alkyl chains behave as hard magnets with Hc>5500 Oeand display a TM higher than 55 K. This intriguing behaviour was studied by density functional theory with the incorporation of a Hubbard term (DFT+U) calculations, unveiling the structural subtleties underlying this observation. Indeed, the different molecular orientation exhibitedby the even/odd alkyl chains, and the orientation of thecovalently linked carboxylic groups modify the intensity ofthe magnetic coupling of both octahedral and tetrahedralin-plane sublattices, thus strongly affecting the magneticproperties of the hybrid. These findings offer an outstanding level of tuning in the molecular design of hybrid magnetic materials based on layered hydroxides.