Copper Phthalate Coordination Polymers Incorporating Kinked Dipyridyl Ligands: An Unprecedented 8-Connected Network and One-Dimensional Chiral Nanobarrels with Hydrophobic Channels Constructed from Septuple Helical Motifs

Copper phthalate coordination polymers incorporating the kinked and hydrogen-bonding-capable imines 4,4′-dipyridylketone (dpk) and 4,4′-dipyridylamine (dpa) have been prepared and structurally characterized by single-crystal X-ray diffraction. {[Cu(pht)(dpk)]·0.33CH3OH}n (1; pht = phthalate) possesses helical subunits built from the fusion of [Cu(dpk)]n 3-fold double helices and [Cu(pht)]n 3-fold helices with opposite handedness. The resulting achiral [Cu(pht)(dpk)]n helices are conjoined by bridging phthalate carboxylate oxygen atoms to construct {Cu2O2} dimeric units, which serve as 8-connected nodes for a three-dimensional (3D) coordination polymer lattice with an unprecedented 364125862 topology, evocative of a 3D Kagome lattice. {[Cu2(pht)2(dpa)]·H2O}n (2) manifests homochiral septuple left-handed [Cu2O2(dpa)]n helices formed by copper ions, phthalate oxygen atoms, and dpa ligands. The septuple helices are bracketed by pht anions to construct chiral one-dimensional nanobarrels with solvent-free “star-shaped” channels. Compounds 1 and 2 display antiferromagnetic [J = −9.85(5) cm−1] and ferromagnetic [J = +1.36(3) cm−1] coupling across their {Cu2O2} dimeric units, respectively.