title: A magnetically isolated cuprate spin-ladder system: synthesis, structures, and magnetic properties.
abstract: We synthesized and characterized two magnetically isolated spin ladders, Cu2(CO3)(ClO4)2(NH3)6 (1) and Cu2(CO3)(ClO4)2(H2O)(NH3)5 (2), which are the first examples of carbonate bridging molecular spin ladders. Compounds 1 and 2 form a ladder configuration by stacking a structural unit composed of two Cu(2+) ions and one CO3(2-), where the Cu-O-Cu interactions form the rungs and legs of each ladder and the counter anions (ClO4(-)) occupy the space between the ladders and ensure their magnetic isolation. A S = 1/2 magnetically isolated spin-ladder model with a ladder-rung magnetic interaction J1/k(B) = 364 K (where J is defined as positive for antiferromagnetic interactions) and a ladder-leg magnetic interaction J2/k(B) = 27.4 K accurately predicts the temperature dependence of the molar magnetic susceptibility for 1. The ladder configuration of 2 is similar to that of 1 except that the CO3(2-) is alternately skewed in different directions in the stacked structural unit. Interestingly, this minor structural variation in 2 results in its remarkably different magnetic behavior; the magnetic susceptibility curve of 2 is accurately described by an alternating chain model with J3/k(B) = 7.26 K and J4/k(B) = 4.42 K.
authors.affiliation: Department of Chemistry, Hiroshima University, Higashi-hiroshima 739-8526, Japan. snishi@hiroshima-u.ac.jp.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Sadafumi
authors.initials: S
authors.lastname: Nishihara
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nakano
authors.forename: Erina
authors.initials: E
authors.lastname: Yoshida
authors.forename: Chisato
authors.initials: C
authors.lastname: Kato
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Ren
authors.forename: Kseniya Yu
authors.initials: KY
authors.lastname: Maryunina
authors.forename: Katsuya
authors.initials: K
authors.lastname: Inoue