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

Abstract

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-Bu 4N 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) Å and β=109.626(8)°. Its crystal structure consist of almost regular columns of [Au(dcdmp) 2] −, stacked along b, surrounded by n-Bu 4N + cations. n-Bu 4N AuBr 2 (tctata) crystallises in triclinic space group P 1 ̄ , Z=2, with unit cell parameters a=10.986(1), b=13.230(2), c=13.791(1) Å, 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 AuBr 2 anions located in alternated cavities between the tctata chains and the cation layers. At last, n-Bu 4N[Au(dcdmp) 2] (tctata) crystallises in monoclinic space group P2 1/ n, Z=4, with unit cell parameters a=10.693(2), b=40.308(7), c=10.870(1) Å, 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 [ nBu 4N] +. In the last two compounds the tctata appears as a planar molecule.