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A new copper-thiolate cluster assembled framework [Cu2(µ4-SCH3)Cl]n (1), has been solvothermally synthesized through in situ reaction viz., in situ ligand generation and metal reduction. Compound 1 represents the first 3D framework based on Atlas-sphere functionalized by single µ2-Cl− groups. DOS calculation reveals the interaction of electronic structures. It is found that the HOMO is mainly distributed on Cl, Cu and S bonding orbitals, while the LUMO is dominated by Cu-Cl antibonding orbitals.

Three Co(II) metal-organic frameworks, namely, {[Co(L)(dpyb)0.5(H2O)2]·3H2O}n (1), {[Co(L)(dpyb)0.5]·CH3CN}n (2), and {[Co2(L)2(dpyp)1.5(H2O)]}n (3) have been hydrothermally synthesized based on a substituted thiophene carboxylic acid 3,3′-(thiophene-2,5-diyl)dibenzoic acid (H2L) and auxiliary N-donor co-ligands 1,4-di(pyridin-4-yl)benzene (dpyb) and 1,3-di(4-pyridyl)propane (dpyp). 1 possesses a 1D double chains structure, which is further extended into a 3D supramolecular framework via O–H···O hydrogen bonds and π···π interactions. 2 shows a novel 2D + 2D→ 2D network with unusual polyrotaxane entanglements of (4, 4)-sql subnets. The two sets of adjacent such networks are further extended via C–H···π interactions into a 3D supramolecular framework. 3 displays a non-interpenetrated 2D sheet with the point symbol {44.62} sql net topology and further extends via π···π interactions into a 3D supramolecular framework. The three MOFs were characterized by IR spectra, elemental analysis, thermal analysis and single crystal X-ray diffraction. In addition, solid-state UV–vis spectra experiments show that 1, 2, and 3 exhibit semiconductive properties with band gap of 2.23, 2.95, and 3.12 eV.

Two coordination polymers, namely [Mn(L)2(H2O)2]n (1) and [Cd2(L)4(H2O)4]n (2) {HL = (benzotriazol-1-yloxy)-acetic acid}, have been synthesized and characterized by single-crystal X-ray diffraction as well as with infrared spectroscopy and elemental analysis. The results reveal that CP1 has 1D double chain structure, while CP2 features a 1D infinite chain structure. Additionally, there both exist O–H···O and O–H···N hydrogen bonds in CP1 and CP2, forming 3D supramolecular structures, respectively. UV-vis absorption spectra of CP1, and photoluminescence property of CP2, have been examined in solid state at room temperature. The result on optical energy gap of 2.80 eV indicates that CP1 is a potential semiconductive material.

Two new isomorphous zinc(II) and nickel(II) supramolecular complexes, [Zn(L)2(H2O)2]n, (1), and [Ni(L)2(H2O)2]n (2) {HL = (benzotriazol-1-yloxy)-acetic acid} have been synthesized under ambient conditions by the self-assembly of HL with Zn(Ac)2·2H2O or Ni(Ac)2·4H2O in the presence of triethylamine. The two complexes have been characterized by single-crystal X-ray diffraction, elemental analysis, and IR spectroscopy. Single-crystal X-ray diffraction shows that the two complexes are isostructural and crystallize in monoclinic crystal system P21/c with similar unit-cell parameters and exhibit one-dimensional infinite chain structures. Adjacent chains are linked by O–H⋯O hydrogen bonds, giving rise to a two-dimensional network and these networks are further extended by weak π⋯π stacking interactions among adjacent aromatic cycles of HL ligands into a three-dimensional framework. In addition, the luminescent property of 1 and UV–Visible absorbance of 2 were also investigated and discussed. Density functional theory (DFT) calculations of the structures, stabilities, orbital energies, and composition characteristics of some frontier molecular orbitals of the two complexes were performed by means of Gaussian 09W package and taking B3LYP basis set.

The design and synthesis of coordination polymers with a self-penetrating architecture has attracted much interest not only due to their interesting structures but also due to their potential applications. 5,5′-Bis(pyridin-4-yl)-2,2′-bithiophene (bpbp), as a conjugated bithiophene ligand, can exhibit trans and cis conformations and this can lead to the construction of a self-penetrating architecture. In addition, the semi-rigid ancillary ligand 4,4′-oxybis(benzoic acid) (H2oba) can adopt different coordination modes, resulting in coordination polymers with high-dimensional skeletons. A new CdII coordination polymer based on mixed ligands, namely poly[diaquapentakis[μ-5,5′-bis(pyridin-4-yl)-2,2′-bithiophene-κ2 N:N′]bis(nitrato-κ2 O,O′)tetrakis(μ3-4,4′-oxydibenzoato)-κ10 O:O,O′:O′′,O′′′;κ6 O:O′:O′′-pentacadmium(II)], [Cd5(C14H14O5)4(NO3)2(C18H12N2S2)5(H2O)2] n , (I), has been synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy and elemental analysis. Single-crystal X-ray diffraction indicates that there are three crystallographically independent CdII cations, three bpbp ligands, two deprotonated oba2− ligands, one nitrate ligand and one coordinated water molecule in the asymmetric unit. One CdII centre is seven-coordinated, exhibiting a distorted {CdN2O5} pentagonal bipyramidal geometry, while the other two Cd centres are both six-coordinated, showing slightly distorted {CdN2O4} octahedral geometries. The most interesting feature is the co-existence of trans and cis conformations in a single net, allowing structural interpenetration via self-threading and yet the expected self-penetrating structure was obtained. Topological analysis shows that the whole three-dimensional framework can be classified as a 3-nodal (4,6,6)-c net with Schläfli symbol {613.82}2{66}, which is a new topology. Furthermore, the luminescence properties of (I) were examined in the solid state at room temperature.

The combination of π-conjugated fluorophores within a hybrid system gives rise to a triphenylamine-functionalized material [Zn(bpba)(NO3)] (1) (Hbpba = 4-(bis(4-(pyridin-4-yl)phenyl)amino)benzoic acid). Compound 1 features a 2D + 2D → 2D parallel polycatenation structure with 63-hcb net. Photophysical studies revealed that the title phase showed superior sensitivity towards p-nitroaniline (p-NA) with a low detection limit (down to ∼0.10 ppm). Specifically, following a new detection route, vapor-sensing experiments using a saturated ethanol solution of nitroaromatic isomers have been established for the first time. Highly sensitive and selective detection of p-NA by the proposed material with a rapid response time (t = 30 s, QE > 90.0%) as compared to that via the control isomers (t = 60s, QE < 6.0%) demonstrates an attractive feasible route and a promising luminescent sensor for nitroaromatic detection.

By employing the conjugated bithiophene ligand 5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene (bibp), which can exhibit trans and cis conformations, two different CuII coordination polymers, namely, poly[[μ-5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene-κ2 N:N′](μ2-4,4′-oxydibenzoato-κ2 O:O′)copper(II)], [Cu(C14H8O5)(C14H10N4S2)] n or [Cu(bibp)(oba)] n , (I), and catena-poly[μ-aqua-bis[μ-5,5′-bis(1H-imidazol-1-yl)-2,2′-bithiophene-κ2 N:N′]bis(μ3-4,4′-oxydibenzoato)-κ3 O:O′:O′′;κ4 O:O′,O′′:O′-dicopper(II)], [Cu2(C14H8O5)2(C14H10N4S2)(H2O)] n or [Cu2(bibp)(oba)2(H2O)] n , (II), have been prepared through one-pot concomitant crystallization and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, powder X-ray diffraction (PXRD) and thermogravimetric (TG) analysis. Single-crystal X-ray diffraction indicates that the most interesting aspect of the structure is the existence of sole trans and cis conformations of the bibp ligand in a single net of (I) and (II), respectively. Compound (I) displays a threefold interpenetrating three-dimensional framework with a 4-connected {65.8} cds topology, whereas (II) features a one-dimensional chain structure. In the crystal of (II), the polymeric chains are further extended through C—H...O hydrogen bonds and C—H...π interactions into a three-dimensional supramolecular architecture. In addition, strong intramolecular O—H...O hydrogen bonds formed between the bridging water molecules and the carboxylate O atoms improve the stability of the framework of (II). Furthermore, solid-state UV–Vis spectroscopy experiments show that compounds (I) and (II) exhibit optical band gaps which are characteristic for optical semiconductors, with values of 2.70 and 2.26 eV, respectively.