Slow Magnetic Relaxation of a 12-Metallacrown-4 Complex with a Manganese(III)-Copper(II) Heterometallic Ring Motif

Alex J Lewis; Elena Garlatti; Francesco Cugini; Massimo Solzi; Matthias Zeller; Stefano Carretta; Curtis M Zaleski

doi:10.1021/acs.inorgchem.0c01410

Slow Magnetic Relaxation of a 12-Metallacrown-4 Complex with a Manganese(III)-Copper(II) Heterometallic Ring Motif

Inorg Chem. 2020 Sep 8;59(17):11894-11900. doi: 10.1021/acs.inorgchem.0c01410. Epub 2020 Aug 19.

Authors

Alex J Lewis¹, Elena Garlatti^{2

3}, Francesco Cugini², Massimo Solzi², Matthias Zeller⁴, Stefano Carretta^{2

3}, Curtis M Zaleski¹

Affiliations

¹ Department of Chemistry and Biochemistry, Shippensburg University, Shippensburg, Pennsylvania 17257, United States.
² Dipartimento di Scienze Matematiche, Fisiche e Informatiche, Università di Parma, 1-43124 Parma, Italy.
³ Udr Parma, INSTM, 1-43124 Parma, Italy.
⁴ Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States.

PMID: 32812746
DOI: 10.1021/acs.inorgchem.0c01410

Abstract

The heterobimetallic metallacrown (MC), (TMA)₂{Mn(OAc)₂[12-MC_{Mn(III)Cu(II)N(shi)}-4](CH₃OH)}·2.90CH₃OH, 1, where TMA⁺ is tetramethylammonium, ^-OAc is acetate, and shi^3- is salicylhydroximate, consists of a Mn^II ion captured in the central cavity and alternating unambiguous and ordered manganese(III) and copper(II) sites about the MC ring, a first for the archetypal MC structure design. DC-magnetometry characterization and subsequent simulation with the Spin Hamiltonian H = -J₁(s₁ + s₃)·s₅ - J₂(s₂ + s₄)·s₅ - J₃Σ_i=1⁴s_i·s_i+1 + d(s_z,1² + s_z,3²) + μ_BΣ_j=1⁵g_js_j·B indicates an S = 5/2 ground state and a sizable axial zero-field splitting on Mn^III. AC-susceptibility measurements reveal that 1 displays slow magnetization relaxation akin to single-molecule magnet (SMM) behavior.