Control of water molecule aggregations in copper 1,4-cyclohexanedicarboxylate coordination polymers containing pyridyl-piperazine type ligands

A series of layered divalent copper coordination polymers containing 1,4-cyclohexanedicarboxylate and long-spanning pyridyl piperazine type ligands exhibits greatly different co-crystallized water molecule aggregations depending on the specific ligands used. Both [Cu(t-14cdc)(4-bpmp)](n) (1, t-14cdc = trans-1,4-cyclohexanedicarboxylate, 4-bpmp = bis(4-pyridylmethyl)piperazine) and {[Cu(t-14cdc)(4-bpfp) (H2O)(2)]center dot 6H(2)O}(n) (2, 4-bpfp = bis(4-pyridylformyl)piperazine) possess 2D (4,4) coordination polymer grids. However I lacks any co-crystallized water and has pinched grid apertures, while 2 manifests infinite water tapes with T6(2)4(2) classification and rectangular grid apertures. {[Cu-2(c-14cdc)(2)(4-bpmp)]center dot 2H(2-)O}(n) (3, c-14cdc = cis-1,4-cyclohexanedicarboxylate) has [Cu-2(c-14cdc)](2) ribbons with paddlewheel dimeric units linked into 2D slabs by 4-bpmp tethers, along with isolated water molecule pairs. In contrast, {[Cu-2(c-14cdc)(2)(4-bPfP)]center dot 10H(2)O}(n) (4) shows a very similar underlying coordination polymer topology but entrains unique decameric water molecule clusters. The minor product {[Cu-2(c-14cdcH)(2) (t-1,4-cdc)(4-bPfP)(2)(H2O)(2)]center dot 2H(2)O}(n) (5) was isolated along with 4; this compound underwent some in situ cis to trans cyclohexane-dicarboxylate ligand isomerization and exhibits a ladder polymer motif. (C) 2013 Elsevier B.V. All rights reserved.