Two series a and b of 3d metal based complexes 1–4 [MII{(4-R-NCOC6H4)2CH}2], (with M = Mn (1), Fe (2), Co (3), Ni (4) and R = H (a) or Me (b)) were synthesised and structurally as well as magnetically characterized.
From the sodium sodate
precursor [(Na(thf)6][Na{(4-Me-NCOC6H3)2CH}2] (1) three isostructural
dinuclear lanthanide complexes [(μ-Cl)LnIII{(4-MeNCOC6H3)2CH}2]2 with
Ln = Gd (2), Dy (3), and Er (4) based on the N,N′-chelating
monoanionic bis(4-methylbenzoxazol-2-yl)methanide
ligand (titled “Mebox”) were synthesized and characterized
by X-ray diffraction and magnetic measurements. The sodium precursor 1 was analyzed via X-ray diffraction and diffusion-ordered
NMR spectroscopy experiments (DOSY-NMR) in order to investigate its
aggregation in solution and the solid state. The sodium analog [(thf)3Na(NCOC6H4)2CH] (1′) based on the bis(benzoxazol-2-yl)-methanide ligand (titled
“box”) was prepared and analyzed for comparison reasons.
From the lanthanide derivatives 2–4, the DyIII complex 3 displays slow relaxation
of magnetization at zero field, with a relaxation barrier of U = 315.7 cm–1. The coupling strength
between the two lanthanide centers was estimated with the GdIII equivalent 2, giving a weak antiferromagnetic coupling
of J = −0.035 cm–1.
Herein, we report the stabilization of nitrene reagents as the source of a nitrogen atom to synthesize nitrogen‐incorporated R1LSi‐N←SiLR2 (1) [L=PhC(NtBu)2; R1=NTMS2, R2=NTMS]. Compound 1 is synthesized by reacting LSi(I)‐SiIL with 3.1 equivalents of Me3SiN3 at low temperature to afford a triene‐like structural framework. Whereas the reaction of the LSi(I)‐SiIL with 2.1 equivalents of Me3SiN3 at room temperature produced silaimine 2 with a central four‐membered Si2N2 ring which is accompanied by a silylene LSi and a cleaved silylene fragment. 1 further reacts with AgOTf at room temperature to yield compound 3 which shows coordination of nitrene to silver with the triflate salt. The compounds 1 and 2 were fully characterized by NMR, mass spectrometry, and X‐ray crystallographic analysis. The quantum mechanical calculations reveal that compounds 1 and 2 have dicoordinated monovalent N atoms having two active lone pairs of electrons. These lone pairs are stabilized by hyperconjugative interactions.
Based on the potassium [{S(tBuN)2(tBuNH)}2K3(tmeda)‐K3{(HNtBu)(NtBu)2S}2] (1) and sodium precursors [S(tBuN)3(thf)3‐Na3SNa3(thf)3(NtBu)3S] (2), [S(tBuN)3(thf)3Na3{(HNtBu)(NtBu)2S}] (3) and [(tmeda)3S‐{Na3(NtBu)3S}2] (4) the syntheses and magnetic properties of three mixed metal triimidosulfite based alkali‐lanthanide‐metal‐cages [(tBuNH)Dy{K(0.5tmeda)}2{(NtBu)3S}2]n (5) and [ClLn{Na(thf)}2{(NtBu)3S}2] with Ln=Dy (6), Er (7) are reported. The corresponding potassium (1) and sodium (2–4) based cages are characterized through XRD and NMR experiments. Preventing lithium chloride co‐complexation led to a significant increase of SMM performance to previously reported sulfur‐nitrogen ligands. The subsequent DyIII‐complexes 5 and 6 display slow relaxation of magnetization at zero field, with relaxation barriers U=77.0 cm−1 for 5, 512.9 and 316.3 cm−1 for 6, respectively. Significantly, the latter complex 6 also exhibits a butterfly‐shaped hysteresis up to 7 K.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.