Bis‐Cyclooctatetraenyl Thulium(II): Highly Reducing Lanthanide Sandwich Single‐Molecule Magnets

Abstract

Divalent lanthanide organometallics are well‐known highly reducing compounds usually used for single electron transfer reactivity and small molecule activation. Thus, their very reactive nature prevented for many years the study of their physical properties, such as magnetic studies on a reliable basis. Herein, the access to rare organometallic sandwich compounds of TmII with the cyclooctatetraenyl (Cot) ligand impacts on the use of divalent organolanthanide compounds as an additional strategy for the design of performing Single Molecule Magnets (SMM). The first divalent thulium sandwich complex with f13 configuration behaving as a single‐molecule magnet in absence of DC field is highlighted.

Correlation between Electronic Configuration and Magnetic Stability in Dysprosium Single Atom Magnets

“…Due to their strong localization, their 4f electrons generally show very limited degree of covalency and preserve an atomic-like character with well-defined integer orbital occupation. Depending on the ligand environment, lanthanide complexes and surface-adsorbed atoms and can be mostly found in either atom-like (4f n ) 4,[11][12][13][14][15] or bulk-like configuration (4f n-1 ) [1][2][3][16][17][18][19][20][21][22][23] . Not only does the 4f occupation determine the magnetic moment and stability of the atom, but it also has an impact on the population of the 6s5d valence orbitals 15,22,24,25 determining the behavior in spin transport measurements 8,[26][27][28] .…”

The Archetypal Homoleptic Lanthanide Quadruple‐Decker—Synthesis, Mechanistic Studies, and Quantum Chemical Investigations

“…Similar to the above-described trivalent compounds, these are commonly isolated as monomeric species where the potassium ions are saturated by Lewis-base-ligands. [23] The inner potassium ions are each bound to one COT 1,4-SiiPr3 ligand in the expected h 8coordination mode (K1-Ct1 = 2.3000( 5) and connected to the neighboring K 2 [Sm II (COT 1,4-SiiPr3 ) 2 ] fragment via a h…”

Synthesis and Structures of Tris(cyclononatetraenyl) Rare-Earth Complexes [Ln(C9H9)3] (Ln = Y, Gd, Tb, Dy, Ho, Er, Tm)

“…[22][23] Our group has extended this strategy for the development of SMMs of divalent Tm, a f 13 metal ion, with the large aromatic Cot ligand. 24 Another important finding is the report of intermediate valent states 25 occurring in these complexes, mostly for Yb and Ce, including the iconic Yb(Cp)3 26 and Ce(Cot)2. 27 In these compounds, the net valency of the metal center is not integer but intermediate and the ground and excited states can be described as a linear combination of several configurations, in which the valence is different.…”