Magnetic properties of lanthanide complexes with nitronyl nitroxides.

Application of the Hubbard Model to Cp*2Yb(bipy), a Model System for Strong Exchange Coupling in Lanthanide Systems

“…Direct overlap is also possible in Ln complexes containing stable radicals such as nitroxyl, yet these complexes display much weaker exchange coupling. [42][43][44][45][46][47] The HMM clearly explains why exchange coupling in 1 and 3 is strong while exchange coupling between Ln centers and ligands containing stable radicals such nitroxyl radicals is much weaker. [42][43][44][45][46][47] Trivalent lanthanide ions have large, negative reduction potentials, so strongly reducing ligands with similarly large, negative reductions potentials are needed to minimize U.…”

Analysis of the Magnetic Exchange Interactions in Yttrium(III) Complexes Containing Nitronyl Nitroxide Radicals

“…In addition, contrary to the mechanism evidenced here, most of the mechanisms discussed in the litterature for Ln(hfac) 3 (NITR) 2 complexes involve either the half-filled 4f orbitals or the virtual 5d and 6s orbitals of the lanthanide ion. 25,27,34,43,46,47,[92][93][94][95] To get a clearer picture of the through-bond NIT-NIT interaction in these lanthanide derivatives, and clarify whether or not the lanthanide orbitals are involved in the exchange mechanism, we are currently investigating the Gd(III) analogue of 1. Gd(III) is indeed a pure spin center and is thus expected to interact isotropically with the NIT radical ligands coordinated to it.…”

“…In these architectures, significant magnetic coupling can be observed that induces 0-, 1-, 2-or 3-dimensional overall magnetic behaviors. [25][26][27][28][29][30][31][32][33] Such materials can also give rise to unique magnetic behavior such as next-nearest neighbor interactions, 34 one-dimensional helimagnetism [35][36][37] or Single…”

“…25,34,[43][44][45][46][47][48] Rationalization of these exchange interactions has been performed initially using angular overlap analysis. 25,46 On the basis of Y(hfac) 3 (NIT-R) 2 investigations, three possible mechanisms for the NIT-NIT interaction have been proposed: (i) direct exchange,…”

Magnetic, thermal and spectral properties of Ni(II) 2,3- , 3,5- and 2,6-dimethoxybenzoates

“…The complexes show paramagnetic properties and they obey the Curie-Weiss law. The values of the Weiss constant, Θ, for all the complexes were found to be negative, which probably arises from a crystal field splitting of the paramagnetic spin state [9][10][11][12][29][30][31][32]. The paramagnetic dependences of values of the magnetic susceptibility as a function of temperatures are given in Table 3.…”