Synthesis, Crystal Structure, and Single‐Molecule Magnetic Properties of a Salen‐type Zn‐Dy‐Zn Complex

Abstract

Single-crystal X-ray diffraction analysis revealed that Dy III was sandwiched between the two ZnL moieties, which was coordinated by three outer OO2 atoms and four inner N2O2 atoms from two Salen-type ligand, respectively, and an oxygen atom of acetic acid molecule completed the eight-coor-

Three angular Zn2Dy complexes showing the effect of remote coordination at Zn and counter ions on slow magnetic relaxation at Dy centres

“…While linear arrangement of Zn 2 Dy is well abundant, [19][20][21][22][23][24] only a few examples of bent structures are known in the literature with similar ligand systems. 15,25 In the present case, the intramolecular p-p and chelate-p stacking interactions among the Schiff bases from two ZnL fragments are mainly responsible for such a high degree of deviation from linearity (Fig. S5, ESI †).…”

“…The classic o-vanillin based salen-type compartmental Schiff base ligand has been widely used to build 3d-4f heterometallic complexes with fascinating magnetic properties. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Recently, we introduced a methylated o-vanillin derivative for the exploration of coordination chemistry with expectation that the methyl substitution at the para position with respect to the phenolic-OH group would increase the electron density on the phenolate oxygen and thus may have significant impact on the crystal field around Dy(III) ions. 27 Accordingly, in the present work, a new Schiff base ligand (H 2 L) was prepared by the reaction of o-phenylenediamine and Me-val in the 1 : 2 molar ratio in methanol with stirring (Scheme 1).…”

“…The Zn-O and Zn-N bond distances vary in the range of 2.007(1)À2.098(6) Å in 1-3, while the apical Zn-X (X = Cl À for 1, Br À for 2 and I À for 3) bond distances are 2.269(2) and 2.276(2), 2.398(1), and 2.616(1) Å, respectively, which are typical for Zn(II) complexes. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] All the complexes experience almost identical deviation of the Zn(II) ions from the mean basal coordination plane by B0.70 Å toward the axially coordinated halide ions. The Dy(III) ions in these complexes are sandwiched by the outer O 2 O donor sites from two ZnL fragments leaving one methoxy-oxygen atom non-coordinated from each fragment and are further coordinated by two aqua ligands to attain an octa-coordination environment around Dy(III) ions.…”

“…9 Additionally, the presence of coordinated Zn(II) ions enhances the negative charge through polarization on the bridging atoms that connect the 3d-4f ions, resulting in a stronger electrostatic field for the lanthanide ions. 10 With the aforesaid consideration, a large number of salen-type compartmental ligands derived from o-vanillin have been successfully applied to develop Zn-Dy [11][12][13][14][15][16][17][18] and Zn-Dy-Zn [19][20][21][22][23][24][25] complexes with a high axial crystal field around the central Dy(III) ion. In some systems, the axial ligand field created by the larger negative charges of phenoxo oxygen donor atoms compared to other donor sites is responsible for the strong easy-axis anisotropy of the Dy(III) ion.…”

Cathecol and Naphtol Groups in Salphen-Type Schiff Bases for the Preparation of Polynuclear Complexes

“…Polynuclear Schiff base complexes are a relevant topic due to their applications in optoelectronic devices [16,17], high thermodynamic stability [18], magnetic materials [19][20][21], sensing, or catalysis [22,23]. Self-assembly of complicated polynuclear complexes can be achieved in many ways such as using Schiff base ligands that can bridge more than one metal.…”