title: (α-DT-TTF)2[Au(mnt)2]: a weakly disordered molecular spin-ladder system.
abstract: The synthesis and characterization of (α-DT-TTF)2[Au(mnt)2] is reported. The magnetic properties of this new salt show that it is still a rare example of an organic spin-ladder. (α-DT-TTF)2[Au(mnt)2] shares the same ladder structure of the DT-TTF and ETT-TTF analogues, and its room temperature conductivity is ∼2 S/cm. Despite the observed donor orientation disorder associated with the thiophenic sulfur atoms, the intermolecular interactions between donor units, calculated using the extended Hückel approximation and a double-ξ basis set, show that the interaction values do not depend on the configuration of the sulfur atom on the thiophenic ring. The insensitivity of the spin-ladder magnetic properties to the donor molecular disorder in (α-DT-TTF)2[Au(mnt)2] is a direct consequence of the negligible contribution of the disordered thiophenic sulfur atom to the HOMO. In the related donor ETT-TTF, this contribution is significant and destroys the magnetic interactions, and no spin-ladder is observed. This compound not only enlarges the number of organic spin-ladder systems in this series of closely related compounds but also provides an interesting example of weakly disordered molecular spin-ladder system.
authors.affiliation: Department of Chemistry, IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa/CFMCUL, Estrada Nacional 10, P-2686-953 Sacavém, Portugal.
authors.forename: Rafaela A L
authors.initials: RA
authors.lastname: Silva
authors.forename: Ana I S
authors.initials: AI
authors.lastname: Neves
authors.forename: Elsa B
authors.initials: EB
authors.lastname: Lopes
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Santos
authors.forename: Joana T
authors.initials: JT
authors.lastname: Coutinho
authors.forename: Laura C J
authors.initials: LC
authors.lastname: Pereira
authors.forename: Concepció
authors.initials: C
authors.lastname: Rovira
authors.forename: Manuel
authors.initials: M
authors.lastname: Almeida
authors.forename: Dulce
authors.initials: D
authors.lastname: Belo
mesh_terms: D018360:Crystallography, X-Ray; D004553:Electric Conductivity; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008958:Models, Molecular; D050607:Organogold Compounds / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D006571:Heterocyclic Compounds; D050607:Organogold Compounds; D013438:Sulfhydryl Compounds; D013876:Thiophenes; C459462:maleinitriledithiolate; C063887:tetrathiafulvalene