Structural and Magnetic Properties of a {GdCu5}2 Metallacrown Dimer with a Disulfonate Linker

• Published in: European journal of inorganic chemistry 2024-02, Vol.27 (5), p.n/a
• Main Authors: Pavlishchuk, Anna V., Zeller, Matthias, Carrella, Luca M., Rentschler, Eva, Bindra, Jasleen K., Dalal, Naresh, Kinyon, Jared, Perera, Kuluni, Pavlishchuk, Vitaly V., Addison, Anthony W.
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Copper; Disulfonate; Ferromagnetism; Gadolinium; Magnetic properties; Mathematical models; Metallacrown; Metathesis; Parameters; Sodium salts
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.202300544

The complex {Na2(H2O)8[GdCu5(GlyHA)5(H2O)4L]2}L2 ⋅ 2.5DMF ⋅ 10.5H2O (1, where GlyHA2−= glycinehydroxamate, L2−= 4,4′‐bis(2‐sulfonatostyryl)biphenyl) was obtained as the outcome of the metathesis reaction of previously reported [GdCu5(GlyHA)5(CO3)(NO3)(H2O)5] ⋅ 3.5H2O with an excess of the disulfonate‘s sodium salt. X‐Ray analysis of 1 shows a dimeric structure in which 15‐metallacrown‐5 units {GdCu5}3+ are arranged in an “edge‐to‐edge” manner by way of two linking disulfonates, L2−. Magnetic studies of polycrystalline 1 over a temperature range of 2–300 K revealed both Gd‐Cu ferromagnetic and Cu‐Cu antiferromagnetic interactions within the metallacrown unit. Experimental χMT vs. T data for 1 were fitted using different theoretical models. A two‐J model, which takes into account both exchange interactions between adjacent copper(II) ions and the Gd‐Cu exchange interactions allows fitting of the χMT vs. T data in the whole temperature range. The values obtained for the exchange parameters are in accord with previously reported parameters for Ln(III)‐Cu(II) 15‐metallacrowns‐5. The 240 GHz powder EPR spectra for 1 were recorded between 30 and 150 K. Linkage of two {GdCu5}3+ 15‐metallacrowns‐5 with rigid disulfonate resulted in a discrete dimer with adjacent metallamacrocycles arranged in “edge‐to‐edge” manner. χMT vs. T data reveal presence of both antiferromagnetic and ferromagnetic exchanges and can be fitted with two‐J model for Gd–Cu and Cu–Cu exchange interactions in {GdCu5}3+ unit.