title: Dithiophene-TTF Salts; New Ladder Structures and Spin-Ladder Behavior.
abstract: (α-DT-TTF)2[Au(i-mnt)2] and (α-DT-TTF)2[Co(mnt)2] are two new salts of the donor α-dithiophene-tetrathiafulvalene with stable diamagnetic anions, both presenting a ladder structure of the donors organized in paired segregated stacks. The first one is isostructural with previously reported closely related compounds and presents a magnetic spin-ladder behavior with J∥= 83.5 K and J⊥ = 110.3 K as estimated from spin susceptibility data in single crystals. (α-DT-TTF)2[Co(mnt)2] presents a new structural type with a different arrangement of pairs of donor stacks, alternating with stacks of dimerized [Co(mnt)2] anions which are however arranged in an uncorrelated fashion perpendicular to the stacking axis. Due to the strong coupling between the disordered anion chains and the donor chains, this compound does not present a magnetic spin-ladder behavior. The low temperature superstructure of (DT-TTF)2[Cu(mnt)2] below the transition at 235 K, previously known to be associated with a lattice doubling along the stacking axis, was solved by synchrotron radiation diffraction in small single crystals. It is found that this dimerization is due to donor charge localization with the spin carriers being associated with fully oxidized donor species alternating with neutral donors.
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Rafaela A L
authors.initials: RA
authors.lastname: Silva
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.|§Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, P-1049-001 Lisboa, Portugal.
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Santos
authors.affiliation: ∥ESRF, The European Synchrotron, 71 Avenue des Martyrs, F-38000 Grenoble, France.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wright
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Joana T
authors.initials: JT
authors.lastname: Coutinho
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Laura C J
authors.initials: LC
authors.lastname: Pereira
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Elsa B
authors.initials: EB
authors.lastname: Lopes
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Sandra
authors.initials: S
authors.lastname: Rabaça
authors.affiliation: ‡Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC) and CIBER-BBN, Campus UAB, E-08193 Bellaterra, Spain.
authors.forename: José
authors.initials: J
authors.lastname: Vidal-Gancedo
authors.affiliation: ‡Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC) and CIBER-BBN, Campus UAB, E-08193 Bellaterra, Spain.
authors.forename: Concepció
authors.initials: C
authors.lastname: Rovira
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Manuel
authors.initials: M
authors.lastname: Almeida
authors.affiliation: †C2TN, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, P-2695-066 Bobadela LRS, Portugal.
authors.forename: Dulce
authors.initials: D
authors.lastname: Belo