The effect of co-ligands on the performance of single-molecule magnet behaviours in a family of linear trinuclear Zn-Dy-Zn complexes with a compartmental Schiff base

abstract

We present herein magneto-structural studies of three heterometallic Zn2Dy complexes: [Zn2Dy(L)2Cl2(H2O)](ClO4)4H2O (1), [Zn2Dy(L)2Br2(H2O)](ClO4)4H2O (2) and [Zn2Dy(L)2(OAc)I(H2O)]I34H2O (3), utilizing a new Schiff base ligand, N,N'-bis(3-methoxy-5-methylsalicylidene)-1,2-diaminocyclohexane (H2L). Complexes 1 and 2 exhibit remarkable magnetic relaxation behaviour with relatively high energy barriers in zero field (Ueff: 244 K for 1 and 211 K for 2) and notable hysteresis temperatures, despite the low local geometric symmetry around the central DyIII ions. The SMM performance of these complexes is further enhanced under an applied magnetic field, with Ueff increasing to 309 K for 1 and 269 K for 2, positioning them as elite members within the Zn-Dy SMM family. These findings emphasize the substantial influence of remote modulation on ZnII beyond the first coordination sphere of DyIII ions on their dynamic magnetic relaxation properties. Ab initio studies demonstrate that the relative orientation of the phenoxo-oxygen donor atoms around the DyIII ion is critical for determining the magnetic anisotropy and relaxation dynamics in these systems. Additionally, experimental and theoretical investigations reveal that the coordination of the bridging acetate towards the hard plane, combined with significant distortion from the ideal ZnO2Dy diamond core arrangement caused by the acetate ion, results in low magnetic anisotropy in complex 3, thereby leading to field-induced SMM behaviour. Overall, this study unveils the effects of co-ligands on the SMM performance in a series of linear trinuclear Zn-Dy-Zn complexes, which exhibit low local geometric symmetry around the DyIII centres. A magneto-structural study unveiling the effects of co-ligands on the SMM performance in structurally similar linear trinuclear Zn-Dy-Zn complexes.

keywords

ZETA VALENCE QUALITY; LANTHANIDE COMPLEXES; ION MAGNET; BASIS-SETS; MAGNETIZATION RELAXATION; ANISOTROPY BARRIER; TB; LN; DYNAMICS; SERIES

subject category

Chemistry

authors

Nandy, R; Jaglicic, Z; Jana, NC; Brandao, P; Bustamante, F; Aravena, D; Panja, A

Groups

G1 - Porous Materials and Nanosystems

Projects

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

A. P. gratefully acknowledges the financial support of this work by the CSIR, New Delhi, India (sanction no. 01/3118/23/EMR-II dated 08.07.23). Z. J. acknowledges the financial support of the Slovenian Research Agency (Grant No. P2-0348). P. B. gratefully acknowledges the financial support of this work by the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). D. A. thanks FONDECYT Regular 1210325 for financial support. Powered@NLHPC: this research was partially supported by the supercomputing infrastructure of the NLHPC (ECM-02).