( n -Bu 4 N) 2 [Fe(dcbdt) 2 ] 2 . Synthesis, crystal structure and magnetic characterisation

Description of the Ground‐State Covalencies of the Bis(dithiolato) Transition‐Metal Complexes from X‐ray Absorption Spectroscopy and Time‐Dependent Density‐Functional Calculations

“…[9,10] Proper determination of the electronic structure of the transition-metal dithiolene complexes requires identification of structural and spectroscopic features that allow the unequivocal detection and characterization of dithiobenzo-A C H T U N G T R E N N U N G semiquinonate(À) radical ions in coordination complexes. Many authors [11,12] have attempted to discern between a dithiolato(2À) and its monoanionic radical form in a given complex by their crystallographically determined structural parameters. The underlying assumption has always been that the phenyl ring has either six equidistant C À C bonds in a thiolate or displays a quinoidal distortion with two alternating shorter C=C bonds and four longer ones in the radical form and, in addition, the CÀS bonds were assumed to shrink upon oxidation of a dianionic thiolate to a mono-A C H T U N G T R E N N U N G anionic radical.…”

A Series of Transition Metal Bis(dicyanobenzenedithiolate) Complexes [M(dcbdt)2] (M = Fe, Co, Ni, Pd, Pt, Cu, Au and Zn)

“…Scheme 2 The monoanionic complexes could be obtained directly after complexation for gold() (2), as green crystals, from the KAuCl 4 salt and also, as described previously, for iron() from FeCl 3 . [12] For cobalt, the monoanionic com-…”

“…The refinement of the crystal structures of compounds 2, 6 and 9 was limited by a small degree of disorder affecting only the cation. The reduced diffraction power of the crystals of compound 5 allowed only the determination of the lattice parameters, which are similar to those of Pt, Pd and Co. Crystallographic data of these compounds are listed in Table 2 The structures observed can be classified into the following four groups: i) the Zn II compound is triclinic, P1, with the metal in a tetrahedral coordination geometry; ii) the other M II complexes (M ϭ Pt, Pd, Co and Cu) are monoclinic, C2/m, and isostructural with the Ni II analogue described previously, [9] presenting a perfectly square-planar geometry; iii) the Co III compound is triclinic, P1, and isostructural with the Fe [12] and Ni [9] analogues, with a strong dimerisation of the M(dcbdt) 2 units and the metal in a square-pyramidal coordination geometry; iv) the M III complexes with M ϭ Au, Cu and Pt are monoclinic, P2 1 /c, and present the complexes as pseudo-dimers.…”

“…[9,12] Along the c and b axes the dimerised anions and the cations are alternating, whereas along the a axis the [Co(dcbdt) 2 ] 2 2Ϫ dimers are arranged in chains due to several weak interactions connecting two side-by-side [Co(dcbdt) 2 ]…”

“…[12] Thus, both for fundamental reasons and also in order to evaluate their possible use as building blocks for conducting or magnetic materials, it appears of obvious interest to study similar complexes with different transition metals.…”