Ag(i) and Zn(ii) coordination polymers with a bulky naphthalene-based dicarboxyl tecton and different 4,4′-bipyridyl-like bridging co-ligands: structural regulation and properties

Abstract

A series of six Ag(I) and Zn(II) coordination polymers, namely, [Ag₂(ndc)]_∞ (1), {[Zn(ndc)(H₂O)](H₂O)}_∞ (2), {[Ag₂(ndc)(4bpy)₂][Ag(4bpy)(H₂O)](ClO₄)(H₂O)₂}_∞ (3), [Zn₅(ndc)₄(4bpy)₂(μ₃-OH)₂]_∞ (4), {[Ag(ndc)(abp)][Ag(abp)](H₂O)₃}_∞ (5), and {[Zn₂(ndc)₂(abp)(H₂O)₂](H₂O)₂}_∞ (6), have been prepared by using 2,3-naphthalenedicarboxylic acid (H₂ndc), an analogue of 1,2-benzenedicarboxylic acid (H₂bdc), and different 4,4′-bipyridyl-like bridging co-ligands 4,4′-bipyridine (4bpy) and trans-4,4′-azobis(pyridine) (abp). The initial complexes 1 and 2 display the unusual two-dimensional (2-D) five-connected (4⁸.6²) and the 2-D three-connected (4.8²) coordination networks, respectively. When two comparable rod-like linkers 4bpy and abp (with different N,N′-donor separations of the molecular backbones of ca. 7 and 9 Å) are further introduced, two one-dimensional (1-D) complexes 3 and 5, a three-dimensional (3-D) coordination framework 4 with (4³)(4³.6³)(4³.6⁵.8²)(4⁴.6⁴.8²)(4¹⁰.6⁵) topology and a 2-D 6³ layered coordination polymer 6 are constructed. A structural comparison of these complexes with those based on the structurally related bdc ligand suggests that the extended π-conjugated system of ndc with different electronic nature and steric bulk play an important role in constructing the supramolecular architectures for 1–6, which are also regulated by different bridging N-donor co-ligands and metal ions. Moreover, complexes 1–6 show strong solid-state luminescence emissions at room temperature that mainly originate from the intraligand transitions of ndc.