Luminescent zinc aliphatic dicarboxylate coordination polymers with bis(4-pyridylmethyl)piperazine: Effect of chain length and steric bulk on topology and water molecule aggregation

•Zinc aliphatic dicarboxylate coordination polymers with 2-D and 3-D topology.•Hydrogen-bonding capable tethering coligand bis(4-pyridylmethyl)piperazine.•2D + 2D mutually inclined interpenetrated (4,4) layers with succinate.•Diamondoid nets with greater interpenetration levels for longer dicarboxylates.•Steric hindrance reduces dimensionality.

Hydrothermal reaction of zinc nitrate, aliphatic dicarboxylic acids, and the long-spanning hydrogen-bonding capable tethering ligand bis(4-pyridylmethyl)piperazine (4-bpmp) has produced seven coordination polymer solids that were characterized via single-crystal X-ray crystallography. [Zn(suc)(4-bpmp)(H2O)2]n (1, suc = succinate) shows 2D + 2D → 3D mutually inclined interpenetrated parallel coordination polymer layers with (4,4) grid topology. {[Zn2(dms)2(4-bpmp)]·2H2O}n (2, dms = 2,2-dimethylsuccinate) exhibits 1-D [Zn2(dms)2]n ribbons featuring {Zn2(OCO)2} dimeric units pillared into 2-D by 4-bpmp ligands. {[Zn(glu)(4-bpmp)]·6H2O}n (3, glu = glutarate) manifests a 3-fold interpenetrated 3-D 66 diamondoid topology with embedded C(10)A(4) water chains. [Zn(22dmg)(4-bpmp)]n (4, 22dmg = 2,2-dimethylglutarate) and [Zn(33dmg)(4-bpmp)]n (5, 33dmg = 3,3-dimethylglutarate) both display stacked zig–zag (4,4) grid layered topologies, and do not entrain any co-crystallized water molecules. Reduction of the steric hindrance by using 3-methylglutarate (3mg) afforded {[Zn(3mg)(4-bpmp)]·3H2O}n (6), which also displays a (4,4) grid topology, but with embedded R(4)A(2) water molecule hexamers connecting to three different layer motifs. [Zn(adp)(4-bpmp)]n (7, adp = adipate) possesses a system of 5-fold interpenetrated diamondoid nets. Thermal and luminescent properties of these materials are discussed herein.

Graphical abstractZinc aliphatic dicarboxylate coordination polymers containing the long-spanning tethering ligand bis(4-pyridylmethyl)piperazine (4-bpmp) show 2D and interpenetrated 3D topologies depending on dicarboxylate length and substituents. [Zn(adipate)(4-bpmp)]n (pictured) possesses a system of 5-fold interpenetrated diamondoid nets.Figure optionsDownload full-size imageDownload as PowerPoint slide