title: Cu(II) and Cu(I) coordination complexes involving two tetrathiafulvalene-1,3-benzothiazole hybrid ligands and their radical cation salts.
abstract: Preparations, crystal structure analyses, and magnetic property investigations on a new Cu(II)(hfac)2 complex coordinated with two TTF-CH═CH-BTA ligands, where hfac is hexafluoroacetylacetonate, TTF is tetrathiafulvalene, and BTA is 1,3-benzothiazole, are reported together with those of its dicationic AsF6(-) salt, [Cu(hfac)2(TTF-CH═CH-BTA)2](AsF6)2, in which each TTF part is in a radical cation state. In these Cu(II)(hfac)2 complexes, two ligands are bonded to the central Cu atom of the Cu(hfac)2 part through the nitrogen atom of the 1,3-benzothiazole ring and occupy the two apical positions of the Cu(hfac)2 complex with an elongated octahedral geometry. These two ligands are located parallelly in a transverse head-to-tail manner, and the Cu(hfac)2 moiety is closely sandwiched by these two ligands. In the AsF6(-) salt of the Cu(hfac)2 complex, each TTF dimer is separated by the AsF6(-) anions and has no overlap with each other within the one-dimensional arrays, resulting in an insulating behavior. Both Cu(hfac)2 complexes showed the simple Curie-like temperature dependence of paramagnetic susceptibilities (χM), indicating that no interaction exists between the paramagnetic Cu(II) d spins. Furthermore, crystal structure analysis and magnetic/conducting properties of a radical cation ReO4(-) salt of the Cu(I) complex with two TTF-CH═CH-BTA ligands, [Cu(TTF-CH═CH-BTA)2](ReO4)2, are also described. Two nitrogen atoms of the ligands are connected to the central Cu(I) in a linear dicoordination with a Cu-N bond length of 1.879(9) Å. Two TTF parts of the neighboring complexes form a dimerized structure, and such a TTF dimer forms a one-dimensional uniform array along the a direction with a short S-S contact of 3.88 Å. Magnetic property measurement suggested the existence of a strongly antiferromagnetic one-dimensional uniform chain of S = 1/2 spins that originate from the radical cation states of the TTF dimers. Due to the construction of the one-dimensional uniform array of the radical cation state of the TTF dimer along the a axis, a semiconducting behavior is observed with σ(rt) = of 6 × 10(-5) S cm(-1) and an activation energy of E(a) = 0.16 eV.
authors.affiliation: Department of Chemistry, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan.
authors.forename: Sayo
authors.initials: S
authors.lastname: Yokota
authors.forename: Keijiro
authors.initials: K
authors.lastname: Tsujimoto
authors.forename: Sadayoshi
authors.initials: S
authors.lastname: Hayashi
authors.forename: Fabrice
authors.initials: F
authors.lastname: Pointillart
authors.forename: Lahcène
authors.initials: L
authors.lastname: Ouahab
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujiwara
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D003300:Copper / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012492:Salts / Q000737:chemistry
chemical_list: D052160:Benzothiazoles; D002412:Cations; D005609:Free Radicals; D008024:Ligands; D009942:Organometallic Compounds; D012492:Salts; C585297:tetrathiafulvalene-1,3-benzothiazole; D003300:Copper