title: Influence of Tuned Linker Functionality on Modulation of Magnetic Properties and Relaxation Dynamics in a Family of Six Isotypic Ln2(Ln = Dy and Gd) Complexes.
abstract: A coordination complex family comprising of six new dinuclear symmetric lanthanide complexes, namely, [Ln2(Lx)2(L')2(CH3OH)2]·yG (H2Lx: three related yet distinct Schiff-base linkers; x = 1-3, according to the nomenclature of the Schiff-base linker employed herein. HL': 2,6-dimethoxyphenol. yG refers to crystallographically assigned guest solvent species in the respective complexes; y = number of solvent molecules; LnIII= Dy/Gd) were isolated employing a mixed-ligand strategy stemming out of a strategic variation of the functionalities introduced among the constituent Schiff-base linkers. The purposeful introduction of three diverse auxiliary groups with delicate differences in their electrostatic natures affects the local anisotropy and magnetic coupling of LnIIIion-environment in the ensuing Ln2dinuclear complexes, consequentially resulting into distinctly dynamical magnetic behaviors among the investigated new-fangled family of isotypic Ln2complexes. Among the entire family, subtle alterations in the chemical moieties render two of the Dy2analogues to behave as single molecule magnets, while the other Dy2congener merely exhibits slow relaxation of the magnetization. The current observation marks one of the rare paradigms, wherein magnetic behavior modulation was achieved by virtue of the omnipresent influence of subtly tuned linker functionalities among the constituent motifs of the lanthanide nanomagnets. To rationalize the observed difference in the magnetic coupling, density functional theory and ab initio calculations (CASSCF/RASSI-SO/POLY_ANISO) were performed on all six complexes. Subtle difference in the bond angles leads to difference in the J values observed for Gd2complexes, while difference in the tunnel splitting associated with the structural alterations lead to variation in the magnetization blockade in the Dy2complexes.
authors.affiliation: Indian Institute of Science Education and Research , Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Soumya
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai, Maharashtra 400076, India.
authors.forename: Gunasekaran
authors.initials: G
authors.lastname: Velmurugan
authors.affiliation: Indian Institute of Science Education and Research , Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Shweta
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai, Maharashtra 400076, India.
authors.forename: Gopalan
authors.initials: G
authors.lastname: Rajaraman
authors.affiliation: State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
authors.forename: Jinkui
authors.initials: J
authors.lastname: Tang
authors.affiliation: Indian Institute of Science Education and Research , Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
authors.forename: Sujit K
authors.initials: SK
authors.lastname: Ghosh