Enforcement of a high-spin ground state for the first 3d heterometallic 12-metallacrown-4 complex

Abstract

Cu(II)(DMF)2Cl2[12-MC(Fe(III)N(Shi))-4](DMF)4·2DMF was synthesized as the first heterometallic transition metal 12-MC-4 complex. The purposeful placement of specific metal ions in the different sites of the metallacrown attains the establishment of a high-spin ground state. Inducing the anticipated superior exchange interactions, the central Cu(II) guest ion averts the common mutual cancellation of the spins, as is observed in the corresponding homometallic compounds.

High-frequency EPR study on Cu4Cu- and Co4Co-metallacrown complexes

“…[1] From the observed slope of the resonance branch, we conclude that we observe a transition from the m S = -3/2 to the m S = 3/2 spin state which is allowed with the spin state mixing due to the off-axial anisotropy. Under this assumption, the effective g-factor amounts to g = 2.66 (2). This is in good accordance to reported Co(II)-ions in distorted octahedral environment.…”

“…HF-EPR measurements were carried out using a phase-sensitive millimeterwave vector network analyzer (MVNA) from AB Millimètre covering the frequency range from 30 to 1000 GHz [3]. We observe one broad resonance feature which implies the presence of a S = 1/2 ground state doublet in agreement of the susceptibility data analysis [2].…”

“…Details of the synthesis method, structure information, and characterisation are reported in Ref. [1,2].…”

Magnetic Properties of LnIII–CuII 15‐Metallacrown‐5 Dimers with Terephthalate (LnIII = Pr, Nd, Sm, Eu)

“…In‐depth studies of the magnetic properties of metallamacrocyclic compounds have given widely spread typical values of exchange parameters for copper(II) and nickel(II) 12‐metallacrown‐4 complexes , . However, there is still a paucity of quantitative magnetochemical data for heteronuclear metallacrowns.…”

Synthesis, Structural, and Magnetic Characterization of a Mixed 3d/4f 12-Metallacrown-4 Family of Complexes

“…This family of compounds has been extensively structurally studied but the authors did focus their investigations mainly towards the effect that the Na I or K I ions had on magnetic measurements and not on the pure {Mn 4 III Ln III (µ-NO)4} 11+ magnetic core, without emphasizing on the evaluation of exchange interactions by fitting of the data. Our group has a great interest in the synthesis and magnetic characterization of MCs and so far has dealt with the isolation of homometallic and heterometallic ones based on transition metal ions [29][30][31][32] 4 ]·(ClO 4 )) for 3 in high yields (>59%). The chemical and structural identities of the compounds were confirmed by single-crystal X-ray crystallography, elemental analyses (C, H, N) and IR spectral data (Supplementary Materials).…”