Solvent Effects on the Assembly of [Cu₂I₂]- or [Cu₄I₄]-Based Coordination Polymers: Isolation, Structures, and Luminescent Properties

Abstract

Four [Cu 2 I 2 ]- or [Cu 4 I 4 ]-based coordination polymers, [CuI(bpp)] n ( 1 ), {[Cu 3 I 3 (bpp) 3 ]·2aniline·MeCN} n ( 2 ), {[Cu 2 I 2 (bpp) 2 ]·2aniline} n ( 3 ), and [Cu 4 I 4 (bpp) 2 ] n ( 4 ), were prepared by solvothermal reactions of CuI or Cu 2 (OH) 2 CO 3 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 1 consists of [Cu 2 I 2 ] 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 [Cu 2 I 2 (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 [Cu 4 I 4 ] 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.