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Sandwich complexes of lanthanides have recently attracted a considerable amount of interest due to their applications as Single Molecule Magnet (SMM). Herein, a comprehensive series of heteroleptic lanthanide sandwich complexes ligated by the cyclononatetraenyl (Cnt) and the cyclooctatetraenyl (Cot) ligand [Ln(Cot)(Cnt)] (Ln=Tb, Dy, Er, Ho, Yb, and Lu) is reported. The coordination behavior of the Cnt ligand has been investigated along the series and shows different coordination patterns in the solid-state depending on the size of the corresponding lanthanide ion without altering its overall anisotropy. Besides the characterization in the solid state by single-crystal X-ray diffraction and in solution by 1 H NMR, static magnetic studies and ab initio computational studies were performed.

Two new dimeric dysprosium(III) complexes, [Dy2(HL)2(SCN)2]·2CH3CN (1) and [Dy2(HL)2(NO3)2]·2CH3CN·2H2O (2), have been assembled using the H3L multidentate ligand (H3L = 2,2′-((((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis((pyridin-2-ylmethyl)azanediyl))bis(methylene))diphenol). The use of different coordination anions for the two complexes results in distinct coordination geometries of the metal sites. The Dy centers in complexes 1 and 2 display capped octahedron and triangular dodecahedron coordination geometries, respectively. Consequently, the two compounds exhibit distinct dc and ac magnetic properties. Complex 1 behaves as a single molecule magnet (SMM) while no SMM behavior is observed for complex 2. Although complexes 1 and 2 possess a similar core of Dy2O2, their different coordination anions lead to two distinct magnetic interactions, namely ferromagnetic and antiferromagnetic, respectively. Ab initio calculations reveal that these interactions may result from strong intramolecular dipolar couplings that are ferromagnetic for 1 but antiferromagnetic for 2, while exchange couplings are antiferromagnetic in both cases. [ABSTRACT FROM AUTHOR]

Sandwich complexes of lanthanides have recently attracted a considerable amount of interest due to their applications as Single Molecule Magnet (SMM). Herein, a comprehensive series of heteroleptic lanthanide sandwich complexes ligated by the cyclononatetraenyl (Cnt) and the cyclooctatetraenyl (Cot) ligand [Ln(Cot)(Cnt)] (Ln=Tb, Dy, Er, Ho, Yb, and Lu) is reported. The coordination behavior of the Cnt ligand has been investigated along the series and shows different coordination patterns in the solid‐state depending on the size of the corresponding lanthanide ion without altering its overall anisotropy. Besides the characterization in the solid state by single‐crystal X‐ray diffraction and in solution by 1H NMR, static magnetic studies and ab initio computational studies were performed. [ABSTRACT FROM AUTHOR]

Keywords: cyclononatetraenyl; lanthanides; organometallics; magnetism; single molecule magnets EN cyclononatetraenyl lanthanides organometallics magnetism single molecule magnets 13480 13480 1 09/28/21 20210924 NES 210924 B High-symmetry organometallic sandwiches b of lanthanides are of current high interest because of their magnetic and optical properties. Cyclononatetraenyl, lanthanides, organometallics, magnetism, single molecule magnets When trivalent lanthanide complexes feature the large monoanionic cyclononatetraenyl (Cnt) ligand, an interesting hapticity switching is observed along with a decrease in the size of the metal center. [Extracted from the article]

Solvation of [(CNT)Ln(η 8 -COT)] (Ln=La, Ce, Nd, Tb, Er; CNT=cyclononatetraenyl, i.e., C 9 H 9 - ; COT=cyclooctatetraendiid, i.e., C 8 H 8 2- ) complexes with tetrahydrofuran (THF) gives rise to neutral [(η 4 -COT)] (Ln=La, Ce) and ionic [Ln(thf) 2 (η 8 -COT)] (Ln=La, Ce) and ionic [Ln(thf) x (η 8 -COT)][CNT] (x=4 (Ce, Nd, Tb), 3 (Er)) species in a solid-to-solid transformation. Due to the severe distortion of the ligand sphere upon solvation, these species act as switchable luminophores and single-molecule magnets. The desolvation of the coordinated solvents can be triggered by applying a dynamic vacuum, as well as a temperature gradient stimulus. Raman spectroscopic investigations revealed fast and fully reversible solvation and desolvation processes. Moreover, we also show that a Nd:YAG laser can induce the necessary temperature gradient for a self-sufficient switching process of the Ce(III) analogue in a spatially resolved manner., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Two new dimeric dysprosium(III) complexes, [Dy 2 (HL) 2 (SCN) 2 ]·2CH 3 CN (1) and [Dy 2 (HL) 2 (NO 3 ) 2 ]·2CH 3 CN·2H 2 O (2), have been assembled using the H 3 L multidentate ligand (H 3 L = 2,2'-((((2-hydroxy-5-methyl-1,3-phenylene)bis(methylene))bis((pyridin-2-ylmethyl)azanediyl))bis(methylene))diphenol). The use of different coordination anions for the two complexes results in distinct coordination geometries of the metal sites. The Dy centers in complexes 1 and 2 display capped octahedron and triangular dodecahedron coordination geometries, respectively. Consequently, the two compounds exhibit distinct dc and ac magnetic properties. Complex 1 behaves as a single molecule magnet (SMM) while no SMM behavior is observed for complex 2. Although complexes 1 and 2 possess a similar core of Dy 2 O 2 , their different coordination anions lead to two distinct magnetic interactions, namely ferromagnetic and antiferromagnetic, respectively. Ab initio calculations reveal that these interactions may result from strong intramolecular dipolar couplings that are ferromagnetic for 1 but antiferromagnetic for 2, while exchange couplings are antiferromagnetic in both cases.

Sandwich complexes of lanthanides have recently attracted a considerable amount of interest due to their applications as Single Molecule Magnet (SMM). Herein, a comprehensive series of heteroleptic lanthanide sandwich complexes ligated by the cyclononatetraenyl (Cnt) and the cyclooctatetraenyl (Cot) ligand [Ln(Cot)(Cnt)] (Ln=Tb, Dy, Er, Ho, Yb, and Lu) is reported. The coordination behavior of the Cnt ligand has been investigated along the series and shows different coordination patterns in the solid-state depending on the size of the corresponding lanthanide ion without altering its overall anisotropy. Besides the characterization in the solid state by single-crystal X-ray diffraction and in solution by 1 H NMR, static magnetic studies and ab initio computational studies were performed., (© 2021 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)