Magnetic and photo-physical investigations into Dy^III and Yb^III complexes involving tetrathiafulvalene ligand

Abstract

International audienceThree lanthanide-based complexes involving a tetrathiafulvalene deriv. (L) in which the lanthanide ion has a pseudo-D4d symmetry have been reported. One is a dinuclear compd. of formula [Dy(hfac)3(L)]2 (1) while the two others are isostructural and described as mononuclear complexes of formulas [Ln(tta)3(L)]·xCH2Cl2 (LnIII = Dy and x = 1.41 (2); Yb and x = 2 (3)). The nuclearity of the species is driven by the nature of the ancillary ligands. Magnetic properties revealed that 1 and 3 behave as single mol. magnets, while 2 does not. The crystal field splitting of the ground multiplet state has been theor. detd. as well as the orientation of the easy axis of the ground MJ state. The results of ab initio calcns. are in agreement with the exptl. detns. of the anisotropy axis. Irradn. of the lowest-energy charge transfer bands of 3 led to an intense and resolved Yb-centered emission which can be correlated to the magnetic data. Thus 3 can be described as a redox-active luminescent field-induced single-mol. magnet

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

“…[20] In the molecular-magnetism field, the luminescence was recently exploited to provide a high level of comprehension of the magnetic properties. [21][22][23][24][25][26][27][28][29] Clearly, the coexistence of magnetic and optical properties enriches the family of multiproperty magnetic objects, and luminescent SMMs have emerged. A certain number of prerequisites are needed to favour the observation of both SMM behaviour and lanthanide luminescence.…”

Magnetic and Photo-Physical Properties of Lanthanide Dinuclear Complexes Involving the 4,5-Bis(2-Pyridyl-N-Oxidemethylthio)-4′,5′-Dicarboxylic Acid-Tetrathiafulvalene-, Dimethyl Ester Ligand

“…The cyclic voltammogram for L shows two mono-electronic oxidations at about 0.75 and 1.13 V, corresponding to the formation of a radical cation and a dication TTF fragment, respectively ( Figure S1). These oxidation potentials are higher than those found for the functionalized TTF donor used in the synthesis of the other dinuclear complexes, due to the direct functionalization of the TTF core with two methyl ester groups [57,58]. The electrochemistry does not highlight significant effects on the oxidation potentials upon coordination of the electron attracting Ln(hfac)3 fragments (Table 3).…”

“…The distortion is visualized by continuous shape measures performed with SHAPE 2.1 [61]. The Dy coordination polyhedra in 1 are the most symmetrical of all the series of similar dinuclear complexes that we have already obtained [57,58].…”

“…We have already demonstrated that such ligands are suitable to obtain SMMs [45][46][47][48][49][50][51] and to sensitize lanthanide luminescence [52][53][54][55][56]. Previously, we associated the Ln(hfac)3·2H2O (hfac − = 1,1,1,5,5,5-hexafluoroacetyacetonate) metallo-precursors with the (4,5-bis(2-pyridyl-N-oxidemethylthio)-4′,5′)-ethylenedithiotetrathiafulvene, -methyldithiotetrathiafulvene [57], or -4′,5′-ethylendioxotetrathiafulvalene ligands, leading to several dinuclear complexes [58].…”

Photo-physical properties of donor-acceptor-radical triad based on functionalized tetrathiafulvalene and nitronyl nitroxide radical

“…Such π-d and π-f systems have shown exciting transport properties such as antiferromagneticsuperconductor or magnetic-field induced superconducting transition [13]- [14] but also have given rise to redox-active [15]- [18], or luminescent single-molecule magnets (SMM) [19]- [20]. The successes in obtaining such multi-property molecular systems were guaranteed thanks to two approaches that allow the observation of interactions between mobile electrons of the organic network and localized electrons of the paramagnetic metals: i) through-space interactions or ii) covalent bonds.…”