Slow relaxation dynamics of a mononuclear Er(iii) complex surrounded by a ligand environment with anisotropic charge density. Issue 3 (19th December 2016)

• Record Type: Journal Article
• Authors: Lim, Kwang Soo; Kang, Dong Won; Song, Jeong Hwa; Lee, Han Geul; Yang, Mino; Hong, Chang Seop
• Is Part Of: Dalton transactions. Volume 46:Issue 3(2017)
• Page Start: 739
• Page End: 744
• Publication Date: 2016-12-19
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt04326g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : The Er complex containing a nitrate ligand exhibits typical single-ion magnet behavior, while slow relaxation is not visible in the Er complex containing neutral water molecules. Abstract : Two sets of isostructural mononuclear compounds, [Ln(LOMe )2 (H2 O)2 ](PF6 ) [1, Ln = Er;3, Ln = Gd; LOMe = CpCo{P(O)(O(CH3 ))2 }3 ] and Ln(LOMe )2 (NO3 ) (2, Ln = Er and4, Ln = Gd), are synthesized by self-assembly of the respective lanthanide ions and tripodal chelate ligands. The Ln ions are encircled by two LOMe ligands, and two water molecules or one nitrate anion. Each octacoordinated Ln center adopts a distorted square antiprism geometry. The Er complex (2 ) chelated by a nitrate anion shows slow dynamics in magnetic relaxation, diagnostic of a single-ion magnet. Quantum tunneling in2 is effectively blocked by application of an external field. Weak intermolecular magnetic interactions occur in2, and are supported by the magnetic behavior of4 . Chemical dilution of Er with the diamagnetic Y ion can nullify magnetic interactions and suppress quantum tunneling. Generation of slow relaxation dynamics in the Er system is related to the anisotropic charge distribution supplied by the coordination of ligands with different charge densities, as observed in the Dy analogue. This suggests that magnetic anisotropy arises in a coordination system when an anisotropic lanthanide ion (Dy and Er) is surrounded by a ligand environment with anisotropic charge density, resulting in slow magnetic relaxation.