Structural and Magnetic Studies on Lanthanide Bis(benzoxazol‐2‐yl)methanides

Abstract

We describe the syntheses, solid-state structures, and magnetic properties of lanthanide(III)-tris(bis(heterocyclo)methanides) [(THF)M{(NCOC 6 H 4 ) 2 CH} 3 ], with M = Tb (1), Dy (2), Ho (3), and Er (4), respectively. The corresponding lanthanide bis(trimethylsilyl)amides have been prepared as starting materials to deprotonate the neutral bis(benzoxazol-2-yl)methane ({NCOC 6 H 4 } 2 CH 2 ) at the central methylene bridge to generate the monoanionic ligand. In the course of this investigations the hitherto unknown holmium tris(bis(trimethylsilyl)amide) is communicated in here. X-ray diffraction data of 1-4 demonstrate an almost planar ligand with metal coordination in an N,N'chelating fashion. Different to their d-metal analogous the magnetic data of the f-metal complexes presented here show no single-molecule magnet (SMM) properties.

A Sodium Sodate as Precursor for Lanthanide Bis(4-R-benzoxazol-2-yl)methanide Single-Molecule Magnets

“…Unfortunately, we did not succeed in bridging two lanthanide atoms by the same ligand via mutual N , O -coordination. However, the steric hindrance of the Mebox ligand, different from the box ligand, prevented a third halide substitution and results in a central Ln 2 Cl 2 four-membered ring . Therefore, this ligand platform is still a well-suited design for bridged systems.…”

“…Those meet all requirements for spectroscopic and magnetic benchmark systems and shine light on the structural and magnetic correlations. The corresponding bis­(benzoxazol-2-yl)­methanide lanthanides are available upon direct reaction of lanthanide bis­(trimethylsilyl)­amide salts, Ln­(HMDS) with Ln = Tb III , Dy III , Ho III , and Er III with the box ligand . These, however, are mononuclear systems and do not exhibit any SMM properties.…”

Alkali Metal Based Triimidosulfite Cages as Versatile Precursors for Single‐Molecule Magnets

“…This phenomenon is caused by spin-orbit coupling effects and all presented χ M T values are in the range of previously reported complexes of this class. [2,20,37,39] We subsequently conducted magnetic susceptibility measurements under a dynamic alternating current (ac) field of 3 Oe for compounds 5-7. For the Er III complex 7, there was no outof-phase signal (χ" M ) typical for SMM behavior under zero dc field, probably due to strong QTM effects.…”

“…(125 MHz, toluene-d 8 , ppm) δ: 58.70 (6 C, CH 2 ), 53.43 (4 C, NC(CH 3 ) 3 ), 53.31 (2 C, NC(CH 3 ) 3 ), 46.38 (12 C, N(CH 3 ) 2 ), 39.95 (6 C, NC(CH 3 ) 3 ). 15 N-HMBC NMR (40 MHz, toluene-d 8 , ppm) δ: À 232.74 (NCH 3 , NCH 2 ), À 236.35 (NC(CH 3 ) 3 ), À 58.52 (NC(CH 3 ) 3 ),).…”

Bis(benzoxazol-2-yl)methanides in main group organometallic syntheses and enquiry-based education

“…[364,371] They were even used as ligands in d-and f-metal complexes to study their properties as single molecule magnets. [372][373][374] With respect to low-valent main group compounds, bis(4-methylbenzoxazol-2-yl)methanide has been used to stabilise the symmetric dialane [ Me BoxAlH]2 as well as the asymmetric [( Me BoxAlH)( Dip NacNacAlH)] and the cation of the latter. [375] Carbenoid compounds of group 13 elements in oxidation state +I have been synthesised by the reaction of sodium or potassium salts of the bulky bis(4-benzhydrylbenzoxazol-2-yl)methane with sources of gallium, indium and thallium.…”