First Heterotrimetallic {3 d‐4 d‐4 f} Single Chain Magnet, Constructed from Anisotropic High‐Spin Heterometallic Nodes and Paramagnetic Spacers

Abstract

Dedicated to Dr. Jean-Pierre Costes as a tribute to his contributions to the development of the chemistry and magnetism of 3d-4f complexesPolymetallic complexes are more and more involved in materials science. The metal ions exert a functional role, carrying magnetic, optical, or redox properties, and a structural one, directing and sustaining the overall architecture of the polymetallic systems. The use of different metal ions in constructing coordination compounds brings novel properties that are not exhibited by the homometallic complexes. [1] Since the first report on the Cu II À Gd III ferromagnetic interaction, [2] the 3d-4f combined chemistry attracted much attention, aiming, in a first stage, to obtain "classical" (3D) molecule-based magnets.[3] The results were rather disappointing: the critical temperatures for the molecular magnets constructed from Cu II and Gd III ions were found to be very low.[4] More recently, the interest of chemists moved towards lanthanides exhibiting a high anisotropy, which is a prerequisite for designing single molecule magnets (SMMs) and single chain magnets (SCMs). The best candidates for this purpose are terbiumA C H T U N G T R E N N U N G (III), dysprosiumA C H T U N G T R E N N U N G (III) and holmium-A C H T U N G T R E N N U N G (III). Indeed, several SMMs, [5] and SCMs, [6] based upon 3d and 4f (Tb III , Dy III , Ho III ) ions, were reported recently. Moreover, it has been shown that even mononuclear Tb III and Dy III complexes fulfil the necessary conditions to exhibit slow relaxation of the magnetization. [7] A plethora of polynuclear complexes with interesting magnetic properties are constructed from two different paramagnetic metal ions (3d-3d', 3d-4d, 3d-5d, 3d-4f, 4d-4f, 5d-4f), while the number of heterotrimetallics is much more limited. Only few 3d-3d'-4f complexes are reported to date.[8] The main problem the chemist is faced with is to obtain pure products in high yield, by avoiding the scrambling of the three different metal ions. A successful synthetic approach consists of self-assembly processes involving preformed 3d-4f oligonuclear cationic complexes and stable metal-containing anions with potentially bridging ligands, for example hexacyanometallates, [M(CN) 6 ] 3À . We have recently shown that bi-and trinuclear 3d-4f species {(CuL) n Ln} (n = 1, 2; L 2À = a dissymetric compartmental Schiff-base ligand) can efficiently act as tectons in designing both high-nuclearity clusters and coordination polymers with various dimensionalities and network topologies.[9] Fol-[a] Dr.

Magnetization plateau as a result of the uniform and gradual electron doping in a coupled spin-electron double-tetrahedral chain

“…It was confirmed that this striking phenomenon is not in conflict with the OYA criterion (1) and may be a direct result of different Landé g-factors of magnetic particles [39][40][41][42][43], quenched disorder [44][45][46] or doping by itinerant particles [47][48][49][50][51]. In the last case, a change of the particle concentration may allow one to tune the value and position of the magnetization plateau in a controlled way.…”

A toolbox of building blocks, linkers and crystallisation methods used to generate single-chain magnets

“…14) [90,91]. The latter site binds a Ln(III) ion so the resulting SCMs contain a 3d-4f building block (Fig.…”

Absence of actual plateaus in zero-temperature magnetization curves of quantum spin clusters and chains

“…Various variants of the Ising-Heisenberg chains have been examined: diamond-chain, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] saw-tooth chain, 29,30 orthogonal-dimer chain, [31][32][33] tetrahedral chain, [34][35][36][37][38] and some special examples relevant to real magnetic materials. [39][40][41][42] In the present work, we will rigorously examine a magnetization process of a few quantum Heisenberg spin clusters and Ising-Heisenberg diamond chain, which will not display strict magnetization plateaus on assumption that some constituent spins have different Landé g-factors and may be a XY-anisotropy of the exchange interaction. Also, the Dzyaloshinskii-Moriya (DM) term in a direction different from that of the magnetic field can lead to the same effect.…”