Journal article
Magnetocaloric effect in 1D-polymers bearing 15-metallacrown-5 {GdCu 5 } 3+ units and anionic oxalate complexes
Dalton transactions : an international journal of inorganic chemistry, v 53, pp 15713-15724
10 Sep 2024
Abstract
Two complexes {[GdCu 5 (GlyHA) 5 (H 2 O) 7 Cr(C 2 O 4 ) 3 ]·11.02H 2 O} n (1) and {{[GdCu 5 (GlyHA) 5 (H 2 O) 6 ]μ 2 -[Cu(C 2 O 4 ) 2 (H 2 O)]} 2 μ 4 -[Cu(C 2 O 4 ) 2 ]·15.8H 2 O} n (2), were obtained as outcomes of the reactions between the cationic hexanuclear {GdCu 5 (GlyHA) 5 } 3+ 15-metallacrown-5 complex (where GlyHA 2− = glycinehydroxamate) and the anionic oxalate complexes K 3 [Cr(C 2 O 4 ) 3 ] or K 2 [Cu(C 2 O 4 ) 2 ]. Both 1 and 2 possess polymeric 1D-chain structures according to X-ray structural analysis. As a consequence of the geometric orientations of the donor atoms in the oxalates from [Cr(C 2 O 4 ) 3 ] 3− , the Cu 5 mean planes of neighboring 15-metallacrown-5 units {GdCu 5 (GlyHA) 5 } 3+ are angled at 75.5° to each other, which leads to formation of a zig-zag motif in the 1D-chains of complex 1. The centrosymmetric complex 2 contains two structurally different bis(oxalato)cuprate anions μ 2 -[Cu(C 2 O 4 ) 2 (H 2 O)] 2− , for one of which, coordination to two adjacent {GdCu 5 (GlyHA) 5 } 3+ units leads to formation of linear 1D-chains in 2, while the second type, μ 4 -[Cu(C 2 O 4 ) 2 ] 2− , is coordinated to four {GdCu 5 (GlyHA) 5 } 3+ units, causing the cross-linking of single 1D-chains into a double-chain 1D coordination polymer. Studies of χ M T vs. T data for 1 and 2 in a 2–300 K temperature range revealed the presence of both ferromagnetic and antiferromagnetic interactions amongst paramagnetic centres. The experimental χ M T vs. T data for 1 were fitted using a model which takes into account exchange interactions between adjacent copper( ii ) ions, the Gd–Cu exchange interactions within {GdCu 5 (GlyHA) 5 } 3+ units and additionally Gd–Cr exchange interactions. Fitting of the χ M T vs. T data for 2 was not possible, since coordination of μ 4 -[Cu(C 2 O 4 ) 2 ] 2− to {GdCu 5 (GlyHA) 5 } 3+ led to the non-equivalence of several Cu–Cu exchange interactions within the metallacrown units and hence a superfluity of fittable parameters. Complexes 1 and 2 are the first examples of 15-metallacrown-5 complexes demonstrating a magnetocaloric effect (−Δ S M at 13 T reaches 24.26 J K −1 kg −1 at 5 K and 19.14 J K −1 kg −1 at 4 K for 1 and 2, respectively).
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Details
- Title
- Magnetocaloric effect in 1D-polymers bearing 15-metallacrown-5 {GdCu 5 } 3+ units and anionic oxalate complexes
- Creators
- Anna V. Pavlishchuk - L.V. Pisarzhevskii Institute of Physical ChemistrySergey V. Kolotilov - L.V. Pisarzhevskii Institute of Physical ChemistryMatthias Zeller - Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USAVitaly V. Pavlishchuk - L.V. Pisarzhevskii Institute of Physical ChemistryFabrice Pointillart - Institut des Sciences Chimiques de RennesAnthony W. Addison - Drexel University
- Publication Details
- Dalton transactions : an international journal of inorganic chemistry, v 53, pp 15713-15724
- Publisher
- Royal Society of Chemistry
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]; Chemistry
- Scopus ID
- 2-s2.0-85204297726
- Other Identifier
- 991021902496904721