Amending the Anisotropy Barrier and Luminescence Behavior of Heterometallic Trinuclear Linear [MIILnIIIMII] (LnIII=Gd, Tb, Dy; MII=Mg/Zn) Complexes by Change from Divalent Paramagnetic to Diamagnetic Metal Ions. Issue 17 (13th March 2015)

• Record Type: Journal Article
• Authors: Das, Sourav; Bejoymohandas, K. S.; Dey, Atanu; Biswas, Sourav; Reddy, M. L. P.; Morales, Roser; Ruiz, Eliseo; Titos‐Padilla, Silvia; Colacio, Enrique; Chandrasekhar, Vadapalli
• Is Part Of: Chemistry. Volume 21:Issue 17(2015)
• Page Start: 6449
• Page End: 6464
• Publication Date: 2015-03-13
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201406666
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The sequential reaction of a multisite coordinating compartmental ligand [2‐(2‐hydroxy‐3‐(hydroxymethyl)‐5‐methylbenzylideneamino)‐2‐methylpropane‐1, 3‐diol] (LH<sub>4</sub>) with appropriate lanthanide salts followed by the addition of [Mg(NO<sub>3</sub>)<sub>2</sub>]<bold>⋅</bold>6 H<sub>2</sub>O or [Zn(NO<sub>3</sub>)<sub>2</sub>]<bold>⋅</bold>6 H<sub>2</sub>O in a 4:1:2 stoichiometric ratio in the presence of triethylamine affords a series of isostructural heterometallic trinuclear complexes containing [Mg<sub>2</sub>Ln]<sup>3+</sup> (Ln=Dy, Gd, and Tb) and [Zn<sub>2</sub>Ln]<sup>3+</sup> (Ln=Dy, Gd, and Tb) cores. The formation of these complexes is demonstrated by X‐ray crystallography as well as ESI‐MS spectra. All complexes are isostructural possessing a linear trimetallic core with a central lanthanide ion. The comprehensive studies discussed involve the synthesis, structure, magnetism, and photophysical properties on this family of trinuclear [Mg<sub>2</sub>Ln]<sup>3+</sup> and [Zn<sub>2</sub>Ln]<sup>3+</sup> heterometallic complexes. [Mg<sub>2</sub>Dy]<sup>3+</sup> and [Zn<sub>2</sub>Dy]<sup>3+</sup> show slow relaxation of the magnetization below 12 K under zero applied direct current (dc) field, but without reaching a neat maximum, which is due to the overlapping with a faster quantum tunneling relaxation mediated through dipole–dipole and hyperfine interactions. Under a small applied dc field of 1000 Oe, the quantum tunneling is almost suppressed and temperature and frequency dependent peaks are observed, thus confirming the single‐molecule magnet behavior of complexes [Mg<sub>2</sub>Dy]<sup>3+</sup> and [Zn<sub>2</sub>Dy]<sup>3+</sup>.</p> </abstract>