Electrical Conductivity and Luminescence in Coordination Polymers Based on Copper(I)-Halides and Sulfur-Pyrimidine Ligands

The solvothermal reactions between pyrimidinedisulfide (pym(2)S(2)) and CuI or CuBr2 in CH2Cl2:CH3CN lead to the formation of [CuIII7(pymS)(4)](n) (pymSH = pyrimidine-2(1H)-thione) (1) and the dimer [Cull(mu-Br)(Br)L](2) (L = 2-(pyrimidin-2-ylamino)-1,3-thiazole-4-carbaldehyde) (2). In the later reaction, there is an in situ S S, S C(sp(2)), and C(sp2)-N multiple bond cleavage of the pyrimidinedisulfide resulting in the formation of 2-(pyrimidin-2-ylamino)-1,3-thiazole-4-carbaldehyde. Interestingly, similar reactions carried out just with a change in the solvent (H2O:CH3CN instead of CH2Cl2:CH3CN) give rise to the formation of coordination polymers with rather different architectures. Thus, the reaction between pym(2)S(2) and CuI leads to the formation of [Cu3I(pymS)(2)](n) (3) and [CuI(pym(2)S(3))] (pym(2)S(3) = pyrimidiltrIsulfide) (4), while [Cu3Br(pymS)(2)](n) (5) is isolated in the reaction with CuBr2. Finally, the solvothermal reactions between CuI and pyrimidine-2-thione (pymSH) in CH2Cl2:CH3CN at different ratios, 1:1 or 2:1, give the polymers [Cu2I2(pymSH)(2)](n) (6) and [Cu2I2(pymSH)] (7), respectively. The structure of the new compounds has been determined by X-ray diffraction. The studies of the physical properties of the novel coordination polymers reveal that compounds 3 and 5 present excellent electrical conductivity values at room temperature, while compounds 1, 3, and 5-7 show luminescent strong red emission at room temperature.