Cu^IIand Cu^ICoordination 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.

Luminescence and Single‐Molecule‐Magnet Behaviour in Lanthanide Coordination Complexes Involving Benzothiazole‐Based Tetrathiafulvalene Ligands

“…Recently, some of us obtained coordination complexes involving neutral and radical cation forms of this ligand. [42] The 4-[6-(1,3-benzothiazol-2-yl)pyridin-3-yl]-4′,5′-bis(methylthio)tetrathiafulvene ligand (L 1 , Scheme 1) was used to elaborate mononuclear SMMs and study the isotopic effect on the slow magnetic relaxation for two polymorphs. [43] In this paper, the influence of the ancillary ligand [ (Table S2).…”

Photo‐ and Electronically Switchable Spin‐Crossover Iron(II) Metal–Organic Frameworks Based on a Tetrathiafulvalene Ligand

“…Thec entral C=Cb ond of the TTF units is 1.41(2) ,which is longer than that of the neutral compound 2. [19] Ther esults clearly confirm that the TTF moiety is in its radical cation state. [20] To confirm the oxidation state of iron in the materials,Xray Photoelectron Spectroscopy (XPS) measurements on 1, 2, 1@I 2 ,a nd 2@I 2 were carried out ( Figure S18).…”

“…Fort he crystal structure of complex 2@I 2 ,the asymmetric unit contains one Fe II atom, one TTF(py) 4 ligand, one ClO 4 À anion, and half aI 3 À anion. [19] Ther esults clearly confirm that the TTF moiety is in its radical cation state. Viewing the structure along the b axis,two types of channels are found, in which I 3 À anions are located.…”

Covalent non-fused tetrathiafulvalene–acceptor systems

“…69 The coordinating ability of sp 2 N atoms was put to work for TTF-BT 40 in a paramagnetic Cu(II)-based complex, which provided by electrocrystallization crystalline radical cation salts with either AsF 6 À or ReO 4 À anions. 70 Rhodanine, which contains a thiazolidine cycle, has also been well used as an electron acceptor moiety in NLO active chromophores. 71 Martín et al 72 described a TTF-rhodanine derivative (44) bearing a cyanomethylene group, which showed an ICT band at l max = 498 nm, oxidation potentials comparable to those of pristine TTF and an irreversible reduction of the acceptor.…”