SMM Behavior Tuned by an Exchange Coupling LEGO Approach for Chimeric Compounds: First 2p-3d-4f Heterotrispin Complexes with Different Metal Ions Bridged by One Aminoxyl Group

Author(s)

Patrascu, Andrei A. ^[1] ; Briganti, Matteo ^{[2, 3, 4]} ; Soriano, Stephane ^[5] ; Calancea, Sergiu ^{[1, 6]} ; Cassaro, Rafael A. Allao ^[7] ; Totti, Federico ^{[2, 3]} ; Vaz, Maria G. F. ^[4] ; Andruh, Marius ^[1]

Affiliation

^[1] Univ Bucharest, Fac Chem, Inorgan Chem Lab, Str Dumbrava Rosie 23, Bucharest 020464 - Romania

^[2] Univ Florence, Dept Chem Ugo Schiff, I-50019 Sesto Fiorentino - Italy

^[3] Univ Florence, INSTM RU, I-50019 Sesto Fiorentino - Italy

^[4] Univ Fed Fluminense, Inst Quim, BR-24020346 Niteroi, RJ - Brazil

^[5] Univ Fed Fluminense, Inst Fis, BR-24210346 Niteroi, RJ - Brazil

^[6] Moldova State Univ, Fac Chem & Chem Technol, MD-2009 Kishinev - Moldova

^[7] Univ Fed Rio de Janeiro, Inst Quim, BR-21941909 Rio De Janeiro - Brazil

• Document type: Journal article
• Source: Inorganic Chemistry; v. 58, n. 19, p. 13090-13101, OCT 7 2019.
• Web of Science Citations: 13

Abstract

Coordination compounds containing three different spin carriers (2p, 3d, and 4f), with the general formula {[}(MDyIII)-Dy-II(LH)-(hfac)(5)] (M = Co, Ni, Mn, Zn), have been obtained using Mannich ligands decorated with a nitronyl-nitroxide fragment. The synthetic approach is general and leads to binuclear 3d-4f complexes, the two metal ions being bridged by one aminoxyl group and by one oxygen atom arising from a hfac(-) ligand. Triangular spin topology affords significant 2p-3d, 3d-4f, and 2p-4f exchange interactions. For the {[}Co(II)Dy(III)Rad] derivative obtained using a nitronyl-nitroxide chiral ligand, a high energy barrier (similar to 200 cm(-1)) and a slow relaxation behavior below 30 K were found and rationalized by ab initio calculations. The improvement of magnetic properties comes from the synergy of optimal single ions properties and exchange couplings contributions where the Co-II-Rad interaction becomes the leading one. The role played by this interaction is clearly proved by the investigation of the magnetic properties of the {[}Zn(II)Dy(III)Rad] derivative, with a much lower energy barrier (12.7 cm(-1)) and by the lack of SMM behavior of the previously reported {[}Co(II)Dy(III)Rad] compound (Chem. Commun. 2017, 53, 6504), with a linear topology of spin carriers and a negligible Co-II-Rad interaction. (AU)

• FAPESP's process: 09/54082-2 - Acquisition of a vibranting sample magnetometer coupled with a superconducting quantum interference device assensor (Squid-VSM) with cryogenic closed cycle
• Grantee: Ernesto Chaves Pereira de Souza
• Support Opportunities: Multi-user Equipment Program