New Binuclear Copper Complexes [(9S3)Cu(CN)Cu(9S3)]X_n (X=BF₄, n=1; X=TCNQ, n=2) (9S3=1, 4, 7‐trithiacyclononane): Syntheses, Crystal Structures and Magnetic Properties

Abstract

The binuclear Cu complex salts of 1, 4, 7‐trithiacyclononane (9S3) with an inorganic anion (BF4)‐ and with an organic radical anion TCNQ‐ (7, 7′, 8, 8′‐tetracyanoquinodimethanide) were synthesized and their molecular and crystal structures were examined in connection with the magnetic properties. The new complex cation [Cu(9S3)CN(9S3)Cu]+ varies its charges and magnetic properties depending on the counter anions; [Cu(9S3)CN(9S3)Cu](BF4) (1) was obtained as diamagnetic colorless crystals, while [Cu(9S3)CN(9S3)Cu](TCNQ)2 (2) was obtained as dark blue crystals with antiferromagnetic properties. Complex 1 crystallized in the monoclinic space group C2/c with a = 26.863(2), b = 7.0878(5), c = 13.4864(8) Å, β = 116.318(2)°. Complex 2 crystallized in the triclinic space group P1¯ with a = 12.521(1), b = 20.2698(8), c = 8.0205(4) Å, α = 100.688(4), β = 93.846(5), γ = 94.953(4)°. Both complexes are comprised of cyano‐bridged two Cu(9S3) ions with tetrahedral coordination. The X‐ray structural study revealed that 1 has two crystallographically equivalent copper(I) atoms, while 2 has two crystallographically independent CuI/II sites. The two CuI/II sites could not be distinguished from the X‐ray structural study. For 2 the IR spectra show that both crystallographically independent TCNQ species were monoanions and are strongly dimerized due to π‐stacking, which well explains their diamagnetic contribution to the magnetic susceptibility and the highly insulating property of this salt. The temperature‐dependent magnetic susceptibility of 2 showed a deviation from the Curie‐Weiss behaviour around 60 K, which indicates a strong antiferromagnetic intermolecular interaction between the copper complexes and that such intermolecular interaction should partly occur via the TCNQ radical anion dimer.

1,3-Dithianes as Assembling Ligands for the Construction of Copper(I) Coordination Polymers. Investigation of the Impact of the RC(H)S2C3H6 Substituent and Reaction Conditions on the Architecture of the 0D–3D Networks

“…Although less common than CuX thioether adducts, the pseudohalide salt CuCN is also known to form both discrete molecular complexes and coordination polymers with varying dimensionalities upon treatment with thioether ligands. Examples are the dinuclear species [(9S3)­Cu­(μ 2 -CN)­(9S3)]­BF 4 (9S3 = 1,4,7-trithiacyclononane) or an 3D network of formula [(Cu­(μ 2 -CN)­(μ 2 -SMe 2 )] n . , Another example of a 3D network assembled by tetrahydrothiophene ligands is [(Cu­(μ 2 -CN)­(μ 2 -THT)] n . When adding a slight excess of L2 to hot suspension of CuCN in MeCN, a greyish microcrystalline solid precipitated rapidly.…”