title: Synthesis, structure, and magnetic properties of an antiferromagnetic spin-ladder complex: bis(2,3-dimethylpyridinium) tetrabromocuprate.
abstract: The complex (2,3-dmpyH)2CuBr4 has been synthesized and its crystal packing determined by single-crystal X-ray diffraction (2,3-dmpyH = 2,3-dimethylpyridinium). The compound crystallizes in the triclinic space group P1. The crystal packing is characterized by the formation of a ladder structure for the CuBr4 anions showing short Br...Br contacts. The rungs of the ladder are formed via a crystallographic inversion center, while the rails are formed via unit cell translations. Variable temperature magnetic susceptibility measurements agree very well with the ladder model [Jrung = -3.10 cm-1 (-4.34 K) and Jrail = -6.02 cm-1 (-8.42 K)]. The assignment as a magnetic ladder is confirmed by first principles bottom-up theoretical calculations which conclude that Jrung = -3.49 cm-1 (-4.89 K) and Jrail = -7.79 cm-1 (-10.9 K), in very good agreement with the experimental values. They also support the absence of additional significant magnetic exchange within the crystals. Thus, (2,3-dmpyH)2CuBr4 represents the second reported example of a weak-exchange limit magnetic ladder (that is, one in which the exchange along the rail is stronger than that across the rung).
authors.affiliation: Department of Physics and Carlson School of Chemistry and Biochemistry, Clark University, 950 Main Street, Worcester, Massachusetts 01610, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Shapiro
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Landee
authors.forename: Mark M
authors.initials: MM
authors.lastname: Turnbull
authors.forename: Joaquim
authors.initials: J
authors.lastname: Jornet
authors.forename: Mercè
authors.initials: M
authors.lastname: Deumal
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Novoa
authors.forename: Michael A
authors.initials: MA
authors.lastname: Robb
authors.forename: William
authors.initials: W
authors.lastname: Lewis