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Mononuclear and Tetranuclear Compounds of Yttrium and Dysprosium Ligated by a Salicylic Schiff-Base Derivative: Synthesis, Photoluminescence, and Magnetism

By Munendra Yadav (1549534), Valeriu Mereacre (1446490), Sergei Lebedkin (1427488), Manfred M. Kappes (1427491), Annie K. Powell (1446481) and Peter W. Roesky (1549540)

Abstract

The Schiff-base (2-aminoethyl)­hydroxybenzoic acid (H<sub>2</sub>L) as a proligand was prepared in situ from 3-formylsalicylic acid and ethanolamine (ETA). The mononuclear {[Y­(HL)<sub>4</sub>]­[ETAH]·H<sub>2</sub>O} (<b>1</b>) and {[Dy­(HL)<sub>4</sub>] [ETAH]·3MeOH·H<sub>2</sub>O} (<b>2</b>) and tetranuclear {[Y<sub>4</sub>(HL)<sub>2</sub>(L)<sub>4</sub>(μ<sub>3</sub>-OH)<sub>2</sub>]·4MeOH·4H<sub>2</sub>O} (<b>3</b>), {[Dy<sub>4</sub>(HL)<sub>2</sub>(L)<sub>4</sub>(μ<sub>3</sub>-OH)<sub>2</sub>]·5­(MeOH)<sub>2</sub>·7H<sub>2</sub>O (<b>4</b>), and {[Dy<sub>4</sub>(HL)<sub>8</sub>(L)<sub>2</sub>]·4MeOH·2H<sub>2</sub>O}­(<b>5</b>) rare-earth metal complexes of this ligand could be obtained as single-crystalline materials by the treatment of H<sub>2</sub>L in the presence of the metal salts [Ln­(NO<sub>3</sub>)<sub>3</sub>·(H<sub>2</sub>O)<sub><i>m</i></sub>] (Ln = Y, Dy). In the solid state, the tetranuclear compounds <b>3</b> and <b>4</b> exhibit butterfly structures, whereas <b>5</b> adopts a rectangular arrangement. Electrospray ionization mass spectrometry data of the ionic compounds <b>1</b> and <b>2</b> support single-crystal X-ray analysis. The yttrium compounds <b>1</b> and <b>3</b> show fluorescence with 11.5% and 13% quantum yield, respectively, whereas the quantum yield of the dysprosium complex <b>4</b> is low. Magnetic studies on the dysprosium compounds <b>4</b> and <b>5</b> suggest the presence of weak antiferromagnetic interactions between neighboring metal centers. Compound <b>4</b> shows single-molecule-magnet behavior with two relaxation processes, one with the effective energy barrier <i>U</i><sub>eff</sub> = 84 K and the preexponential factor τ<sub>0</sub> = 5.1 × 10<sup>–9</sup> s

Topics: Biophysics, Biochemistry, Pharmacology, Biotechnology, Hematology, Plant Biology, Environmental Sciences not elsewhere classified, Chemical Sciences not elsewhere classified, Physical Sciences not elsewhere classified, yttrium compounds 1, quantum, acid, Electrospray ionization mass spectrometry data, Compound, 3 show fluorescence, tetranuclear compounds 3, presence, ETA, energy barrier Ueff, H 2L, dysprosium compounds 4, preexponential factor τ0, ETAH, Ln, Dy, 4 exhibit butterfly structures
Year: 2015
DOI identifier: 10.1021/ic5014957.s001
OAI identifier: oai:figshare.com:article/2211253
Provided by: FigShare
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