5,6-Dicyano-2,3-dithiopyrazine (dcdmp) chemistry: Synthesis and crystal structure of Au(III)(dcdmp)2 complexes and 2,3,7,8-tetracyano-1,4,6, 9-tetraazothianthrene

Article abstract of DOI:10.1016/j.poly.2004.02.019

As an effort to explore new complexes of the 2,3-dicyano-5,6- dimercaptopyrazyne (dcdmp) ligand with different transition metals, different salts containing both the Au(dcdmp)₂^- complex and the new species 2,3,7,8-tetracyano-1,4,6,9-tetraazothianthrene (tctata), were obtained and characterized. n-Bu₄N Au(dcdmp)₂ crystallises in monoclinic space group C2/c, Z=8 with unit cell parameters a=35.147(4), b=9.527(1), c=21.792(2) ? and β=109.626(8)°. Its crystal structure consist of almost regular columns of [Au(dcdmp)₂] ^-, stacked along b, surrounded by n-Bu₄N⁺ cations. n-Bu₄N AuBr₂ (tctata) crystallises in triclinic space group P1?, Z=2, with unit cell parameters a=10.986(1), b=13.230(2), c=13.791(1) ?, α=79.150(9)°, β=69.663(6)°, γ=70.254(9)°. The crystal packing is made by zig-zag chains of tctata separated by layers of cations, with AuBr₂ anions located in alternated cavities between the tctata chains and the cation layers. At last, n-Bu₄N[Au(dcdmp)₂] (tctata) crystallises in monoclinic space group P2₁/n, Z=4, with unit cell parameters a=10.693(2), b=40.308(7), c=10.870(1) ?, β=92.16(1)°. Its crystal structure can be seen has a mix of those of the two preceding compounds. It consists of bidimensional layers composed of out of registry parallel zig-zag chains of alternating tctata and [Au(dcdmp)₂]^- units. The adjacent layers are separated by layers of [nBu₄N]⁺. In the last two compounds the tctata appears as a planar molecule.