A dinuclear Co(iii)/Co(ii) complex based on the H2pmide ligand showing field-induced SMM behaviour. Issue 1 (7th December 2022)

• Record Type: Journal Article
• Authors: Cabrosi, Daiana; Cruz, Carlos; Paredes-García, Verónica; Alborés, Pablo
• Is Part Of: Dalton transactions. Volume 52:Issue 1(2022)
• Page Start: 175
• Page End: 184
• Publication Date: 2022-12-07
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt03492a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : We report a combined computational and experimental study of the field-induced SMM behaviour of a Co(ii )/Co(iii ) dinuclear complex with a pair-like H-bond intermolecular interaction. Abstract : We report the synthesis, structural characterization and SMM behaviour of a new mixed valence Co(ii )/Co(iii ) dinuclear complex bearing the H2 pmide ligand. Well defined molecule pairs are observed in the crystal structure, bound through H-bond interactions directed by aqua ligands. From DC magnetometry data, a spin-only Hamiltonian approach including an axial zero-field splitting term seems to be enough for reasonable modelling, with a sizeable D parameter close to 40 cm −1 . The first order orbital contribution is extensively quenched due to strong distortion from octahedral symmetry of the Co(ii ) site. Quantum computation at the CASSCF level supports this interpretation. To model low temperature magnetization data, the H-bond intermolecular exchange interaction is required, with a magnitude close to −1 cm −1, well supported by broken-symmetry DFT computation. This exchange is highly anisotropic due to the existence of a well isolated Kramers doublet at the Co(ii ) site. AC magnetic susceptibility shows field-induced SMM behaviour with competing Orbach and Raman relaxation pathways as well as a quantum tunnelling process at the lowest probed temperatures. The Orbach thermal barrier agrees with the expected one from combined experimental and quantum computed DC magnetometry analysis.