Structural Studies of Transition Metal Complexes with 4,5-Bis(2-pyridylmethylsulfanyl)-4‘,5‘-ethylenedithiotetrathiafulvalene:  Probing Their Potential for the Construction of Multifunctional Molecular Assemblies

Abstract

Three divalent transition metal complexes of 4,5-bis(2-pyridylmethylsulfanyl)-4',5'-ethylenedithiotetrathiafulvalene have been prepared and crystallographically characterized. The isostructural Co(II) and the Ni(II) complexes show octahedral geometries around the metal ions with the coordination sites occupied by the pyridyl nitrogen atoms and the thioether sulfur atoms of the ligand and cis coordination of the halide ions. Cyclic voltammetry reveals that the complexation leads to a small anodic shift in the first oxidation potential of the TTF system.

Tetrathiafulvalene-based group XV ligands: Synthesis, coordination chemistry and radical cation salts

“…Two different families of Co II complexes containing TTF-pyridines have been reported so far. The first one, described by Liu and Decurtins [114,45], is based on the coordination of the CoBr 2 fragment by tetradentate 4,5-bis(2-pyridyl-methylsulfanyl)-4 ,5 -ethylenedithio-TTF ligands such as 51, 54a and 54b to give Co1, Co2 and Co3, respectively (Scheme 47), and has been conventionally synthesized upon reaction of the ligands with the CoBr 2 ·H 2 O precursor in MeCN. Alternatively, the 2-pyridyl units have been replaced on the EDT-TTF-bis(thiomethyl) scaffold by 2-quinolinyl fragments in 54c to afford the corresponding Co II complex Co4 [45].…”

“…The solid state structures have been determined in the case of the complexes Co1 (Fig. 18) [114] and Co2 [45], showing in each case a distorted octahedral coordination pattern around the Co II center, as well as a segregation of the inorganic and donor moieties in the packing diagrams, thus favoring the establishment of some short intermolecular S· · ·S contacts. The equatorial coordination plane is formed by the two bromide anions, with Co-Br distances of 2.49-2.52 Å, and the two sulfanyl sulfur atoms, with Co-S distances of 2.51-2.54 Å, while the axial positions are occupied by the pyridyl N atoms, with Co-N distances of 2.17 Å.…”

“…The NiCl 2 complex Ni2 (Fig. 26) shows an octahedral coordination with the Ni ion cis coordinated to two chloride ions bound to two trans pyridyl nitrogen atoms and two sulfanyl sulfur atoms [114]. The TTF unit is coplanar with the NiCl 2 moiety.…”

“…(a) Molecular geometry of the Ni2 complex in its neutral form and[114] (b) its oxidation product Ni3, in its polyiodide salt[120].…”

Electroactive Bisiminopyridine Ligands: Synthesis and Complexation Studies

“…In order to address this challenge, considerable effort has been devoted in associating the TTF moiety with an inorganic component and various organic mono-or polydentate ligands, and their corresponding electroactive metal complexes have therefore been reported [6]. For example, metal complexes of phosphines [7][8][9][10][11][12], dithiolates [13], acetylacetonates [14], pyridines [15][16][17], bipyridines [18,19] and more recently of Schiff bases [20][21][22] have been synthesized. Pyridine based Schiff bases ligands such as 2,6-bis(imino)pyridyl, with chelating abilities, form stable complexes, with various transition metals, which have been extensively used as catalysts for olefin polymerization [23,24].…”