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

Abstract 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)(H 2 O) 2 ] n ( 1 , suc = succinate) shows 2D + 2D → 3D mutually inclined interpenetrated parallel coordination polymer layers with (4,4) grid topology. {[Zn 2 (dms) 2 (4-bpmp)]·2H 2 O} n ( 2 , dms = 2,2-dimethylsuccinate) exhibits 1-D [Zn 2 (dms) 2 ] n ribbons featuring {Zn 2 (OCO) 2 } dimeric units pillared into 2-D by 4-bpmp ligands. {[Zn(glu)(4-bpmp)]·6H 2 O} n ( 3 , glu = glutarate) manifests a 3-fold interpenetrated 3-D 6 6 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)]·3H 2 O} 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.