Topological diversity in copper aromatic meta-dicarboxylate coordination polymers with bis(pyridylformyl)piperazine coligands

Hydrothermal synthesis has afforded divalent copper coordination polymers containing bis(4-pyridylformyl)piperazine (4-bpfp) tethers and aromatic meta-dicarboxylate ligands. {[Cu(ip)(4-bpfp)]·2H2O}n (1, ip = isophthalate) possesses a (4, 4) rectangular grid structure with an unusual ABCD stacking pattern along a 41 screw axis. Sterically bulky substituents in the 5-position of the isophthalate ligands reduced the coordination polymer dimensionality, with [Cu2(tBuip)2(4-bpfp)(H2O)2]n (2, tBuip = 5-tert-butylisophthalate) and {[Cu(MeOip)(HMeOip)2(4-bpfp)]·3H2O}n (3, MeOip = 5-methoxyisophthalate) displaying 1D polymeric ladder and chain motifs, respectively. Compound 3 possesses a rare twofold interpenetrated binodal supramolecular hms net with (63)(698) topology. Longer meta-disposed acetate pendant arms induced a doubly interpenetrated 3D primitive cubic topology in {[Cu2(1,3-phda)2(H2O)2(4-bpfp)]}n (4, 1,3-phda = 1,3-phenylenediacetate), which possesses antiferromagnetically coupled {Cu2O2} kernels (J = −6.14(8) cm−1).

Graphical abstractFour divalent copper coordination polymers containing bis(4-pyridylformyl)piperazine (4-bpfp) tethers and aromatic meta-dicarboxylate ligands have been characterized. {[Cu(isophthalate)(4-bpfp)]·2H2O}n has a rectangular grid structure with an unusual ABCD stacking pattern. Sterically bulky substituents in the 5-position of the isophthalate ligands reduced the coordination polymer dimensionality. Longer pendant arms induced a doubly interpenetrated 3D primitive cubic topology based on antiferromagnetically coupled {Cu2O2} dimers.Figure optionsDownload full-size imageDownload as PowerPoint slide