title: Bis-phenoxido and bis-acetato bridged heteronuclear {Co(III)Dy(III)} single molecule magnets with two slow relaxation branches.
abstract: Two bis-μ-phenoxido-bis-μ-acetato heterobimetallic {Co(III)Dy(III)} complexes and , formulated as [Co(III)Dy(III)L(μ-OAc)2(NO3)2] derived from the comparable hexadentate Schiff bases N,N'-ethylenebis(3-ethoxysalicylaldimine) and N,N'-ethylenebis(3-methoxysalicylaldimine) were synthesized and X-ray structure analysis confirms their nearly identical structures. These are the first examples of bis(μ-phenoxido)-bis(μ-carboxylato) {Co(III)Dy(III)} systems. The AC susceptibility measurements show that both complexes exhibit a field-induced slow magnetic relaxation with two relaxation branches. While the high-frequency process spans the usual range of the relaxation time for analogous single molecule magnets (τ0 ∼ 10(-7) s), the low-frequency branch is as slow as τ ∼ 0.1 s at T = 1.9 K and B = 0.2 T.
authors.affiliation: Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009, India. sm_cu_chem@yahoo.co.in and Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisbon, Portugal.
authors.forename: Susanta
authors.initials: S
authors.lastname: Hazra
authors.affiliation: Department of Chemistry, FPV, University of SS Cyril and Methodius, Trnava, Slovakia. roman.boca@stuba.sk.
authors.forename: Ján
authors.initials: J
authors.lastname: Titiš
authors.affiliation: Department of Chemistry, FPV, University of SS Cyril and Methodius, Trnava, Slovakia. roman.boca@stuba.sk.
authors.forename: Dušan
authors.initials: D
authors.lastname: Valigura
authors.affiliation: Department of Chemistry, FPV, University of SS Cyril and Methodius, Trnava, Slovakia. roman.boca@stuba.sk.
authors.forename: Roman
authors.initials: R
authors.lastname: Boča
authors.affiliation: Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009, India. sm_cu_chem@yahoo.co.in.
authors.forename: Sasankasekhar
authors.initials: S
authors.lastname: Mohanta