Structural Diversity and Properties of Six 2D or 3D Metal–Organic Frameworks Based on Thiophene-Containing Ligand

Six new coordination polymers, {[Zn2(DPT)2(btc)­(Hbtc)]·2H2O}n (1), {[Cd­(DPT)­(Hbtc)­(H2O)]·4H2O}n (2), {[Co­(DPT)­(Hbtc)]·1/2DPT}n (3), {[Zn­(DPT)­(oba)]·11H2O}n (4), {[Co2(DPT)2(oba)2]·DMF·3H2O}n (5), and {[Zn4(DPT)2(bdc)4(H2O)2]·2H2O·DMA}n (6), have been obtained from
the self-assembly of the heterocycle ligand DPT with different metal
salts, in the presence of coligands (DPT = 2,5-dipyridine-thiophene,
H3btc = 1,3,5-benzenetricarboxylate, H2oba =
4,4′-oxybis­(benzoate), H2bdc = 1,4-benzenedicarboxylate,
DMF = N,N-dimethylformamide, DMA
= N,N-dimethylacetamide). Their
structures have been characterized by single crystal X-ray analysis.
Compounds 1–3 are 2D motifs, of which 1 and 2 are joined via H-bond bridges to give
3D supramolecular architectures. Complex 4 is a 2D network
constructed from left- and right-handed helical chains. Complex 5 has a 3-fold interpenetrating 3D pcu framework. Complex 6 features a polycatened
structure, which can be parallel/parallel catenated with two other
equivalent bilayer ones to form a 2D → 3D framework. The photoluminescence
properties of the compounds 1, 2, 4, and 6 have been examined in solid states at
room temperature, and they have been found to exhibit yellow photoluminescence.
In addition, the UV–visible spectra are also depicted in detail.