Coordination Chemistry of 2,2'-Bipyridyl- and 2,2':6',2″-Terpyridyl-Substituted BEDT-TTFs: Formation of a Supramolecular Capsule Motif by the Iron(II) Tris Complex of 2,2'-Bipyridine-4-thiomethyl-BEDT-TTF

Molecules of tris(2,2'-bipyridine-4-thiomethyl-BEDT-TTF)iron(II) (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) assemble in pairs to form a novel supramolecular capsular structure in the solid state. Three BEDT-TTF residues from one complex lie in the three grooves between coordinated bipyridines of the other complex, and vice versa, to form a capsule with 3-fold rotational symmetry and an internal volume of ca. 160 Å(3). Further aspects of the coordination chemistry of this ligand, its 6-substituted isomer, and the 2,2':6'2″-terpyridyl-4'-thiomethyl-BEDT-TTF analogue are described.

Fused Donor–Acceptor Ligands in RuII Chemistry: Synthesis, Electrochemistry and Spectroscopy of [Ru(bpy)3−n(TTF-dppz)n](PF6)2

Three ruthenium(II) polypyridine complexes of general formula [Ru(bpy)(3-n)(TTF-dppz)n](PF6)2 (n=1-3, bpy=2,2'-bipyridine), with one, two or three redox-active TTF-dppz (4',5'-bis(propylthio)tetrathiafulvenyl[i]dipyrido[3,2-a:2',3'-c]phenazine) ligands, were synthesised and fully characterised. Their electrochemical and photophysical properties are reported together with those of the reference compounds [Ru(bpy)3](PF6)2, [Ru(dppz)3](PF6)2 and [Ru(bpy)2(dppz)](PF6)2 and the free TTF-dppz ligand. All three complexes show intraligand charge-transfer (ILCT) fluorescence of the TTF-dppz ligand. Remarkably, the complex with n=1 exhibits luminescence from the Ru(2+)-->dppz metal-to-ligand charge-transfer ((3)MLCT) state, whereas for the other two complexes, a radiationless pathway via electron transfer from a second TTF-dppz ligand quenches the (3)MLCT luminescence. The TTF fragments as electron donors thus induce a ligand-to-ligand charge-separated (LLCS) state of the form TTF-dppz- -Ru(2+)-dppz-TTF(+). The lifetime of this LLCS state is approximately 2.3 micros, which is four orders of magnitude longer than that of 0.4 ns for the ILCT state, because recombination of charges on two different ligands is substantially slower.

First trinuclear paramagnetic transition metal complexes with redox active ligands derived from TTF: Co2M(PhCOO)6(TTF-CHCH-py)2·2CH3CN, M = CoII, MnII

The first paramagnetic homo- and hetero-metallic trinuclear complexes with redox active ligands derived from TTF are synthesized, the central metal ion has an octahedral coordination sphere while the outer Co(II) ions are in a distorted bipyramidal surrounding, bearing TTF-ligands, the magnetic properties show antiferromagnetic coupling leading to a magnetic ground state.

Co(II)−Co(II) Paddlewheel Complex with a Redox-Active Ligand Derived from TTF

A new trimethyltetrathiafulvalene (Me3TTF) derivative Me3TTF-CH=CH-py bearing a pyridyl was synthesized and coordinated to a cobalt(II) benzoate dimer, having paddlewheel core structure, leading to a complex formulated as Co2(PhCOO)4(Me3TTF-CH=CH-py)2. Single-crystal X-ray diffraction studies of the complex performed at 293 and 100 K evidenced the existence of a weak metal-metal interaction. Magnetic studies revealed an antiferromagnetic behavior, which is explained as the result of the direct exchange between metal centers.

A Dinuclear Ni(II) Complex with Two Types of Intramolecular Magnetic Couplings: Ni(II)−Ni(II) and Ni(II)−TTF•+

A dinuclear Ni(II) complex involving tetrathiafulvalene (TTF) radicals as ligands has been prepared and characterized, [Ni2(mu-Cl)2(L*+)2(I3)4(I2)3.(H2O)2.(C4H8O)3 (1), L = 4,5-bis(2-pyridylmethylsulfanyl)-4',5'-ethylenedithiotetrathiafulvalene. There are two types of intramolecular magnetic exchange interactions, namely one ferromagnetic Ni(II)-Ni(II) and one antiferromagnetic Ni(II)-TTF*+. This study is new in the respect of revealing a magnetic exchange interaction between a TTF*+ radical and a paramagnetic transition metal ion. This is due to the fact of a direct binding of the transition metal ion to the skeleton of the TTF*+ radical.

One-Dimensional μ-Chloromanganese(II)−Tetrathiafulvalene (TTF) Coordination Compound

A new tetrathiafulvalene derivative 1 bearing a single pyridine group and its coordination complex 2, with stoichiometry [Mn(mu-Cl)Cl(1)2(CH3OH)]n, have been synthesized and fully characterized. The complex 2 shows an extended chain structure, which is potentially favorable for electrical conductivity. Notably, this is the first monohalogen-bridged Mn(II) polymer exhibiting a moderate antiferromagnetic coupling between the Mn(II) centers.

Copper(i/ii) complexes of a bis(tetrathiafulvalene)-2,2′-bipyridine: synthesis, characterization, magnetic and electrochemical properties

The coordination ability of the electroactive TTF-based chelating ligand 5,5'-bis(4,5-bis(thiomethyl)-4'-carbamoyltetrathiafulvalene)-2,2'-bipyridine (L) has been tested with Cu(I) and Cu(II) centres. [(L)2Cu(I)](PF6), [(L)2Cu(II)](OTf)2 and [(L)Cu(II)(DMF)3](OTf)2 have been synthesized. A single-crystal X-ray analysis was performed on [(L)Cu(II)(DMF)3](OTf)2, showing a distorted octahedral geometry around the Cu(II) centre, and the formation of dimeric units in the solid state through weak coordination in apical position of an amide oxygen atom from a neighbouring complex. Magnetic data show that the paramagnetic metallic centres are isolated, in agreement with the solid-state structure. Electrochemical measurements were performed on the three complexes and in all cases the Cu(I)/Cu(II) and TTF/TTF+*/TTF2+ redox processes were observed.