Two dinuclear GdIII clusters based on isobutyric acid and nicotinic acid with large magnetocaloric effects

Two dinuclear Gd-III cluster complexes with the formulas [Gd-2(iba)(6)(bipy)(2)] (1) and [Gd-2(nic)(6)(H2O)(4)] (2) (Hiba = isobutyric acid, Hnic = nicotinic acid and bipy = 2,2 , bipyridine) have been constructed by using gadolinium oxide as Gd-III ion source under hydrothermal conditions. Although both 1 and 2 exhibit dinuclear structures, the coordination fashions are totally different. In 1, the carboxylate groups of Hiba take syn-syn-mu(2)-eta(1):eta(1), syn-syn-mu(2)-eta(1):eta(2) and syn-mu-eta(1):eta(1) modes and bipy acts as the chelating ligand. While the carboxylate groups of Hnic display syn-syn-mu(2)-eta(1):eta(1) and syn-mu-eta(1):eta(1) modes in 2 and two water molecules take part in coordination. Magnetic studies reveal weak ferromagnetic couplings and significant magnetic entropy changes with -Delta S-max(m) = 29.3 J kg(-1) K-1 and 27.4 J kg(-1) K-1 (Delta H = 7 T), respectively. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Two dinuclear Gd-III cluster complexes were constructed using gadolinium oxide as the Gd-III ion source under hydrothermal conditions. They exhibit different coordination fashions and show weak ferromagnetic couplings with significant magnetic entropy changes.