Ling Qin

Structure-property relationship of homochiral and achiral supramolecular isomers obtained by one-pot synthesis.

Two supramolecular isomers, {[Co(L)(OBA)]·H(2)O}(n) (1), {[Co(5)O(2)(L)(2)(OBA)(3)]·7DMF}(n) (2), have been synthesized by one-pot reactions. Compound 1 has a homochiral architecture with low connectivity, and compound 2 is an achiral 3D framework with high 12-connectivity. It is unprecedent to get homochiral and achiral supramolecular isomers by one-pot synthesis.

Chiral 3D/3D hetero-interpenetrating framework with six kinds of helices, 3D polyrotaxane and 2D network via one-pot reaction

Three MOFs including novel architectural features were synthesized via one-pot reaction. Reaction time, temperature and ratio of ligands were found to influence the formation of the three compounds and we obtained conditions to synthesize the three MOFs in purely individual phase directly.

Syntheses, characterizations and properties of five new metal–organic complexes based on flexible ligand 4,4′-(phenylazanediyl)dibenzoic acid

Five new metal–organic frameworks have been synthesized under hydrothermal conditions, in CH3CN–H2O, DMF–CH3CH2OH–H2O and DMA–H2O, namely, [ZnL(bimx)0.5]n (1), {[CoL(4,4′-bipy)]·DMF}n (2), {[CdL(4,4′-bipy)]·DMF}n (3), {[ZnL(bibp)]·DMA·(H2O)2}n (4), {[CoL(bpyb)0.5]·(H2O)2}n (5) (bimx = 1,4-bis(imidazol-1-ylmethyl)benzene, 4,4′-biby = 4,4-pyridine, bibp = 4,4′-bis(imidazol-1-yl)biphenyl, bpyb = 1,4-bis(4-pyridyl)benzene, H2L = 4,4′-(phenylazanediyl)dibenzoic acid. These complexes were characterized by elemental analysis, IR spectroscopy, TG and X-ray single-crystal diffraction. In compounds 1, 2 and 3, the bimx, 4,4′-bipy and L2− anions act as bidentate ligands assembling with metal cations to form two-dimensional (2D) sheets. The sheets are stacked in ABAB fashion and accumulate into a 3D framework. Compound 4 possesses a 3D→3D 4-fold interpenetrating architecture with {65·8} topological net, which is similar to the cds topology. Compound 5 also displays a 3D structure with {44·610·8} topology. The photochemical properties were investigated in the solid state at room temperature. The luminescent properties of compounds 1, 3 and 4 are discussed in detail. The UV-vis absorption spectra of compounds 2 and 5 are tested and discussed. In addition, the magnetic properties of compound 5 also are tested and simply analyzed.

Two pairs of isomorphism and two 3D metal–organic frameworks based on a star-like ligand tri(4-pyridylphenyl)amine

Six novel metal–organic frameworks (MOFs) have been synthesized in this paper, which are based on a N-centered ligand TPPA, namely, [Cd(TPPA)(fuma)]n (1), {[Zn(TPPA)(suc)]·5(H2O)·DMA}n (2), [Co(TPPA)(bhf)]n (3), [Zn(TPPA)(bhf)]n (4), [Co(TPPA)(oba)]n (5), and [Cd(TPPA)(oba)]n (6), [TPPA = tri(4-pyridylphenyl)amine, H2fuma = fumaric acid, H2suc = succinic acid, H2bhf = 2,2′-bis(4-carboxyphenyl)hexafluoropropane, H2oba = 4,4′-oxybis(benzoic acid)]. Compound 1 reveals a 4-fold interpenetrating 3D framework with AFUQOH topology. Compound 2 reveals a 2-fold interpenetrating 3D network with large void space (up to 37.6%). Compounds 3 and 4 are isomorphic 2D networks. Different from compounds 3 and 4, compounds 5 and 6 show 2D → 3D parallel polycatenation of undulated square layers. In addition, photochemical properties of compounds and the ligands in the solid state have been studied.

Construction of a series of metal–organic frameworks with a neutral tetradentate ligand and rigid carboxylate co-ligands

The solvothermal reaction of a neutral tetradentate ligand, different bivalent metal salts and two rigid carboxylate co-ligands gave six metal–organic frameworks (MOFs): [Zn(L)(Hbdc)(bdc)0.5]·1.5H2O (1), [Zn2(L)(bdc)2(H2O)]·2H2O (2), [Cd(L)(bdc)(H2O)]·2H2O (3), [Ni(L)(bdc)(H2O)]·H2O (4), [Co3(L)(btc)2(H2O)4] (5), [Zn3(L)(btc)2(H2O)4] (6) (L = 1,1′-oxybis[3,5-dipyridine]-benzene, H2bdc = 1,4-benzenedicarboxylate, H3btc = 1,3,5-benzenetricarboxylate). Compounds 1 and 2 have been co-crystallized in a one-pot reaction. In compound 1, L and H2bdc ligands link Zn centers to generate a two-dimensional (2D) sheet structure which is further connected by intermolecular hydrogen bonds to form a 3-fold interpenetrating 3D fsc-3,4-C2/c array. Single crystal X-ray diffraction analysis reveals that compound 2 features a 3D self-interpenetrated network with {4·6·83·10}{4·63·82}{64·82} topology. For compounds 3 and 4, the binuclear metal secondary building unit (SBU) assembles with mixed ligands, L and H2bdc, to construct a 3D α-Po structure. Compounds 5 and 6 are isostructural and show 3-fold interpenetrated pte/Cmmm->P2/c structures.

Anion-selectivity of cationic cluster–organic nanospheres based on a nest-shaped [MS4Cu3X3] clustermonomer with a ditopic ligand

Three heterothiometallic cluster–organic nanospheres have been synthesized and characterized. They own identical cationic cluster–organic nanoball frameworks and show selectivity towards charge-balancing anions. It is also interesting that the morphology of the as-prepared particles can be tuned by simply varying the polarity of the solvent.

The synthesis, structure and third-order nonlinear optical effect of a new 2D cluster polymer based on a [WS4Cu4]2+ SBU and 1,2-di(pyridin-4-yl)ethane

The self-assembly reaction of a multinodal preformed cluster with 1,2-di(pyridin-4-yl)ethane as the organic ligand afforded the 2D cluster polymer (1), {[(WS4Cu4)I2(dpe)2](DMF)4}n. There is a cavity between each two nearby dpe ligands in 1. The [WS4Cu4]2+ units are fixed by I− ions, which is attributed to the multinodal feature of the W–S–Cu secondary building units, and therefore, the cavities in 1 are settled. The NLO properties show that 1 exhibits an optical self-focusing behavior and reverse saturable absorption effects. This work provides us with useful clues to further explore the 2D W–Cu–S-based cluster polymer with cavities.

Structures and applications of metal–organic frameworks featuring metal clusters

Metal–organic frameworks (MOFs), self-assembled from metal ions or metal clusters with organic ligands, are well known for their intriguing structure, permanent porosity, and tunable properties and have shown great prospect for various applications. In the present review, we mainly highlight recent significant examples of metal clusters in our team and provide a comprehensive review on the structure of metal cluster-based MOFs and their applications including for sensing metal ions, small molecules and gases, nitroaromatics and explosives, as well as many other applications. We classified two different coordination polymers: (i) homometallic coordination polymers (examples of coordination polymers with single and mixed types of secondary building units) and (ii) heterometallic coordination polymers (examples of coordination polymers based on metal–oxygen clusters and W–Cu–S clusters).

Syntheses, characterization, and properties of five coordination compounds based on the ligand tetrakis(4-pyridyloxymethylene)methane

A nonplanar tetrahedral pyridine ligand has been synthesized and applied to assemble five metal–organic frameworks (MOFs) with novel structural features under solvothermal conditions, namely, {[Cu2(TPOM)(adi)2](H2O)4}n (1), {[Zn2(TPOM)(glu)2](H2O)8}n (2), {[Cd2(TPOM)(1,4-chdc)2(H2O)4](H2O)4}n (3), {[Ni(TPOM)(suc)(H2O)2](H2O)2}n (4), and {[Zn2(TPOM)(1,4-chdc)(NO3)2](H2O)2}n (5) (TPOM = tetrakis(4-pyridyloxymethylene)methane, adi = adipic acid, glu = glutaric acid, chdc = 1,4-cyclohexanedicarboxylic acid, suc = succinic acid). These compounds were characterized by elemental analyses, IR spectroscopy and X-ray single-crystal diffraction. Compounds 1 and 3 reveal 3-fold interpenetrating 3D frameworks with sqc969 and new topologies, while compound 2 possesses a 2-fold interpenetrating 3D framework with qtz topology. Compound 4 exhibits a non-interpenetrating 3D structure with the extension of the cage structure, in which there are only two pyridine nitrogen atoms in TPOM involved in the coordination. It is different from compounds 1–3, which may take distinct coordination modes under different conditions. In compound 5, the coordination mode of TPOM is also different from those of compounds 1–3; it is a 2D structure with a 2-fold interpenetrating framework.

Syntheses, characterization, and magnetic properties of novel divalent Co/Ni coordination polymers based on a V-shaped pyridine ligand and dicarboxylate acids

Solvothermal reactions of 3,5-bis(4-pyridyl)-pyridine (BPYPY) with 1,4-benzenedicarboxylate (1,4-bdc) and trans-1,4-cyclohexanedicarboxylic acid (trans-chdc) in the presence of Co(II) and Ni(II) salts in DMF/H2O or DMA/CH3CN/H2O produced three new compounds, namely, {[Co3(BPYPY)2(1,4-bdc)3(H2O)6]}n (1), {[Ni3(BPYPY)2(1,4-bdc)3(H2O)6]}n (2), {[Co(BPYPY)(trans-chdc)0.5(NO3)]·(H2O)}n (3). These compounds were characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Compounds 1 and 2 are isomorphous and present 3,4-connected 3-fold interpenetrating tfz network with a point symbol of {63}2{64·8·10}3. Compound 3 exists binuclear Co clusters which are linked by BPYPY and trans-chdc to generate a 4-connected cds network with the point symbol of {65·8} and displays antiferromagnetic characteristics. In addition, the thermal stabilities of these new compounds have also been discussed in detail.