SMM Behavior Tuned by an Exchange Coupling LEGO Approach for Chimeric Compounds: First 2p-3d-4f Heterotrispin Complexes with Different Metal Ions Bridged by One Aminoxyl Group.

Coordination compounds containing three different spin carriers (2p, 3d, and 4f), with the general formula [MDy(LH)(hfac)] (M = Co, Ni, Mn, Zn), have been obtained using Mannich ligands decorated with a nitronyl-nitroxide fragment. The synthetic approach is general and leads to binuclear 3d-4f complexes, the two metal ions being bridged by one aminoxyl group and by one oxygen atom arising from a hfac ligand. Triangular spin topology affords significant 2p-3d, 3d-4f, and 2p-4f exchange interactions.

Magnetic Cationic Copper(II) Chains and a Mononuclear Cobalt(II) Complex Containing [Ln(hfac)] Blocks as Counterions.

Four new heterospin compounds with molecular formula {[Cu(hfac)(TlTrzNIT)][Ln(hfac)]} ·CH (Ln = Gd (1), Tb (2), or Dy (3)) and [Co(hfac)(TlTrzNIT)][Dy(hfac)] (4), where hfac is hexafluoroacetylacetonato and TlTrzNIT is the nitronylnitroxide radical 1-( m-tolyl)-1 H-1,2,3-triazole-4-(4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were obtained. All structures were determined by single-crystal X-ray diffraction. In compounds 1-3, the TlTrzNIT radical is bridge-coordinated to copper(II) ions, leading to positively charged copper(II)-radical chains containing [Ln(hfac)] as counterions.

Magnetic anisotropy and spin-parity effect along the series of lanthanide complexes with DOTA.

Spotting trends: Upon going from Tb(III) to Yb(III) centers in the complexes of the DOTA(4-) ligand, a reorientation of the easy axis of magnetization from perpendicular to parallel to the Ln-O bond of the apical water molecule is experimentally observed and theoretically predicted (SMM=single-molecule magnet). Only ions with an odd number of electrons show slow relaxation of the magnetization.