title: Significant enhancement of energy barriers in dinuclear dysprosium single-molecule magnets through electron-withdrawing effects.
abstract: The effect of electron-withdrawing ligands on the energy barriers of Single-Molecule Magnets (SMMs) is investigated. By introducing highly electron-withdrawing atoms on targeted ligands, the energy barrier was significantly enhanced. The structural and magnetic properties of five novel SMMs based on a dinuclear {Dy2} phenoxo-bridged motif are explored and compared with a previously studied {Dy2} SMM (1). All complexes share the formula [Dy2(valdien)2(L)2]·solvent, where H2valdien = N1,N3-bis(3-methoxysalicylidene) diethylenetriamine, the terminal ligand L = NO3(-) (1), CH3COO(-) (2), ClCH2COO(-) (3), Cl2CHCOO(-) (4), CH3COCHCOCH3(-) (5), CF3COCHCOCF3(-) (6), and solvent = 0.5 MeOH (4), 2 CH2Cl2 (5). Systematic increase of the barrier was observed for all complexes with the most drastic increase seen in 6 when the acac ligand of 5 was fluorinated resulting in a 7-fold enhancement of the anisotropic barrier. Ab initio calculations reveal more axial g tensors as well as higher energy first excited Kramers doublets in 4 and 6 leading to higher energy barriers for those complexes.
authors: Chemistry Department, University of Ottawa , 10 Marie Curie, Ottawa, ON, K1N6N5, Canada.
authors: Fatemah
authors: F
authors: Habib
authors: Gabriel
authors: G
authors: Brunet
authors: Veacheslav
authors: V
authors: Vieru
authors: Ilia
authors: I
authors: Korobkov
authors: Liviu F
authors: LF
authors: Chibotaru
authors: Muralee
authors: M
authors: Murugesu