Influence of alcoholic solvent and acetate anion coordination mode variations on structures and magnetic properties of heterometallic Zn2Dy2 tetranuclear clusters. Issue 46 (12th November 2018)

• Record Type: Journal Article
• Authors: Ke, Hongshan; Wei, Wen; Zhang, Yi-Quan; Zhang, Jun; Xie, Gang; Chen, Sanping
• Is Part Of: Dalton transactions. Volume 47:Issue 46(2018)
• Page Start: 16616
• Page End: 16626
• Publication Date: 2018-11-12
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt03983f
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : We clarify that slight modifications of the synthetic conditions generate two Zn2 Dy2 clusters with acetate anion coordination mode variation and different magnetic behaviors. Abstract : The present work clarifies how slight modifications of the synthetic conditions ( e.g., employment of different alcoholic solvents) can result in the variation of the coordination mode of an acetate anion yielding two structurally similar heterometallic Zn2 Dy2 tetranuclear clusters with formulas [Zn2 Dy2 (L)4 (CH3 COO)2 (CH3 CH2 OH)2 ]·2CH2 Cl2 ·0.5H2 O (1 ) and [Zn2 Dy2 (L)4 (CH3 COO)2 (CH3 OH)2 ]·4CH2 Cl2 ·2CH3 OH·0.1H2 O (2 ), where H2 L is ( E )-4-( tert -butyl)-2-((2-hydroxy-3-methoxybenzylidene)amino)phenol. Complexes1 and2 were synthesized by varying the alcoholic solvent employed in the synthesis. The ethanol solvent in1 led to the acetate anion being coordinated to the Dy III ion in bidentate chelating mode while the methanol solvent in2 generated the acetate anion coordinated to the Dy III ion in bridging mode. Such a subtle change of the coordination mode of the acetate anion on the Dy III ion imposes a significant effect on the distinct dynamic relaxation in1 and2 . The magnetic properties of1 and2 were characterized through SQUID magnetometry and theoretical calculations to determine the effective energy barrier, energy levels, magnetic anisotropy and intracluster magnetic exchange coupling parameters. Both tetramers show frequency dependence of the out-of-phase ac magnetic susceptibility signal under zero applied dc field associated with single-molecule magnetic behaviour. The effective energy barriers of1 and2 are 115.4 and 104.2 cm −1, respectively. Theoretical calculations suggest that the different magnetic behaviours between1 and2 are mainly due to the coordination mode variations of the acetate anion on the Dy III site. The present result highlights how a subtle modification in the reaction alcoholic solvent resulted in two structurally similar tetranuclear Zn2 Dy2 examples with different magnetic behaviours.