Solvent effects on the assembly of [Cu2I2]- or [Cu4I4]-based coordination polymers: Isolation, structures, and luminescent properties

Four [Cu2I2]- or [Cu4I4]-based coordination polymers, [CuI(bpp)](n) (1), {[Cu3I3(bpp)(3)]center dot 2aniline center dot MeCN)(n) (2), {[Cu2I2(bpp)center dot 2aniline)(n) (3), and [Cu4I4(bPP)(2)](n) (4), were prepared by solvothermal reactions of CuI or Cu-2(OH)(2)CO3 with 1,3-bis(4-pyridyl)propane (bpp) in different solvent systems. The preparation of 2 or 3 is involved in the in situ formation of aniline molecules and the reduction of Cu(II) to Cu(I). These compounds were characterized by elemental analysis, IR, and single crystal X-ray diffraction. Compound I consists Of [Cu2I2] dimeric cores that link the neighboring ones via bpp bridges to form a one-dimensional double-bridged polymeric chain. Compound 2 or 3 has a similar chain structure in which the shape and size of the [Cu2I2(bPP)(2)](2) cavities that are occupied by MeCN/aniline or aniline solvent molecules are different from those of 1. Compound 4 has an intriguing two-dimensional 4-fold interpenetrated network in which each cubanelike [Cu4I4] core acts as a rare seesaw- shaped four-connecting node to interconnect four other equivalent ones via bpp bridges. The results did provide interesting insights into solvent effects on the construction of cluster-based coordination polymers. In addition, the photoluminescent properties of 1-4 in the solid state at ambient temperature were also investigated.