Construction of (CuX)2n Cluster-Containing (X = Br, I; n=1, 2) Coordination Polymers Assembled by Dithioethers ArS(CH2)mSAr (Ar = Ph, p-Tol; m=3, 5): Effect of the Spacer Length, Aryl Group, and Metal-to-Ligand Ratio on the Dimensionality, Cluster Nuclearity, and the Luminescence Properties of the Metal-Organic Frameworks

Reaction of Cut with bis(phenylthio)propane in a 1:1 ratio yields the two-dimensional coordination polymer [{Cu(mu(2)-I)2Cul{mu-PhS(CH2)(3)SPh}(2)](n) (1). The 2D-sheet structure of 1 is built up by dimeric Cu2I2 units, which are connected via four bridging 1,3-bis(phenylthio)propane ligands. In contrast, treatment of 2 equiv of CuI with 1,3-bis(phenylthio)propane in MeCN solution affords in a selfassembly reaction the strongly luminescent metal-organic 2D-coordination polymer [Cu4I4{mu-PhS(CH2)(3)Ph}(2)](n) (2), in which cubane-like Cu-4(mu(3)-I)(4) duster units are linked by the dithioether ligands. The crystallographically characterized one-dimensional (1D) compound [{Cu(mu(2)-Br)(2)Cu}{mu-PhS(CH2)(3)SPh}(2)], (3) is obtained using Cu Br. The outcome of the reaction of PhS(CH2)(5)SPh with CuI also depends of the metal-to-ligand ratio employed. Mixing CuI and the dithioether in a 2:1 ratio results in formation of [Cu4I4{mu-PhS(CH2)(5)Ph}(2)](n) (4) in which cubane-like Cu-4(mu(3)-I)(4) clusters are linked by the bridging dithioether ligand giving rise to a 1D necklace structure. A ribbon-like 1D-polymer with composition [{Cu(mu(2)-I)(2)Cu}{mu-PhS(CH2)(5)SPh}(2)](n) (5), incorporating rhomboid Cu2I2 units, is produced upon treatment of Cul with 1,5-bis(phenylthio)pentane in a 1:1 ratio. Reaction of Cu Br with PhS(CH2)(5)SPh produces the isomorphous 1D-compound [{Cu(mu(2)-Br)(2)Cu}{mu-PhS(CH2)(5)SPh}(2)](n) (6). Strongly luminescent [Cu4I4{mu-p-TolS(CH2)(5)STol-p}(2)](n) (7) is obtained after mbdng 1,5-bis(ptolylthio)pentane with CuI in a 1:2 ratio, and the 2D-polymer [{Cu(mu(2)-I)(2)Cu}(2){mu-p-TolS(CH2)(5)STol-p}(2)](n) (8) results from reaction in a 1:1 metal-to-ligand ratio. t)nder the same reaction conditions, 1D-polymeric [{Cu(mu(2)-Br)(2)Cu}{mu-p-TolS(CH2)(5)STol-p}(2)](n) (9) is formed using Cu Br. This study reveals that the structure of the self-assembly process between CuX and ArS(CH2)(m)SAr ligands is hard to predict. The solid-state luminescence spectra at 298 and 77 K of 2 and 4 exhibit very strong emissions around 535 and 560 nm, respectively, whereas those for 1 and 5 display weaker ones at about 450 nm. The emission lifetimes are longer for the longer wavelength emissions (>1.0 mu s arising from the cubane species) and shorter for the shorter wavelength ones (<1.4 mu s arising from the rhomboid units). The Br-containing species are found to be wealdy fluorescent.