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

Anna V. Pavlishchuk, Sergey V. Kolotilov, Matthias Zeller, Samuel E. Lofland, Anthony W. Addison

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Metathesis of the isomorphous 15-metallacrown-5 complexes {[LnCu5(GlyHA)5(SO4)(H2O)6.5]}2(SO4)·6H2O (LnIII = Pr, Nd, Sm, Eu; GlyHA2– = glycinehydroxamate) with excess p-bdc2– (p-bdc2– = terephthalate) gave pairs of isomorphous complexes {[LnCu5(GlyHA)5(CO3)(H2O)4]2(p-bdc)}·15H2O [Ln = Pr (1) and Nd (2)] and {[LnCu5(GlyHA)5(SO4)(H2O)x]2(p-bdc)}·yH2O [Sm (3) x = 5, y = 12; Eu (4), x = 4, y = 14] as outcomes of partial sulfate replacement. Complexes 1–4 are discrete dimers with two 15-metallacrown-5 blocks {LnCu5}3+, a bridging p-bdc2– and a bidentate capping anion on each Ln3+. The anion caps in 1 and 2 are carbonates from atmospheric CO2 capture, while in 3 and 4 the anion caps are sulfates. Between 3 K and 300 K, intrametallacycle antiferromagnetic exchange interactions amongst the Cu2+ dominate the magnetic properties of 1–4, while for the Ln3+, spin-orbit coupling and crystal field effects are significant, the former being greater for Sm3+ and Eu3+. The experimental χMT vs. T data were fitted with an additive model reflecting the dominance of the Cu···Cu superexchange, while Ln3+···Cu2+ exchange interactions were taken into account through a molecular field approach. The best-fit values (–2JCu–Cu) for the intercopper superexchange interactions range from 88 to 120 cm–1; the g-factors, spin-orbit coupling (λ) and axial crystal field splitting (Δ) parameter values are typical for LnIII.

Original languageEnglish (US)
Pages (from-to)3504-3511
Number of pages8
JournalEuropean Journal of Inorganic Chemistry
Volume2018
Issue number30
DOIs
StatePublished - Aug 15 2018

All Science Journal Classification (ASJC) codes

  • Inorganic Chemistry

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