Tong-Liang Hu

New Three-Dimensional Porous Metal Organic Framework with Tetrazole Functionalized Aromatic Carboxylic Acid: Synthesis, Structure, and Gas Adsorption Properties

5-(1H-Tetrazol-1-yl)isophthalic acid (H(2)L) reacts with Cu(II) ion forming a new metal-organic framework {[CuL]·DMF·H(2)O}(∞) (1) (DMF = N,N-dimethylformamide), with a rutile-related type net topology. Compound 1 possesses a 3D structure with 1D channels that can be desolvated to yield a microporous material. Adsorption properties (N(2), H(2), O(2), CO(2), and CH(4)) of the desolvated solid [CuL] (1a) have been studied, and the results exhibit that 1a possesses fairly good capability of gas sorption for N(2), H(2), O(2), and CO(2) gases, with high selectivity ratios for O(2) over H(2) at 77 K and CO(2) over CH(4) at 195, 273, and 298 K. Furthermore, 1a has excellent O(2) uptake at 77 K and a remarkably high quantity of adsorption for CO(2) at room temperature (298 K) and atmospheric pressure, suggesting its potential applications in gas separation or purification.

Zn(II) coordination architectures with mixed ligands of dipyrido[3,2-d ∶ 2′,3′-f]quinoxaline/2,3-di-2-pyridylquinoxaline and benzenedicarboxylate: syntheses, crystal structures, and photoluminescence properties

Five new Zn(II) metal–organic coordination polymers, [Zn2(L1)2(Dpq)2]·H2O (1), [Zn(L2)(Dpq)(H2O)] (2), [Zn(L3)(Dpq)(H2O)]2 (3), [Zn(Dpdq)(L3)] (4) and [Zn(Dpdq)(L4)]·H2O (5) (Dpq = dipyrido[3,2-d∶2′,3′-f]quinoxaline, Dpdq = 2,3-di-2-pyridylquinoxaline, H2L1 = benzene-1,2-dicarboxylic acid, H2L2 = benzene-1,3-dicarboxylic acid, H2L3 = benzene-1,4-dicarboxylic acid, H2L4 = biphenyl-4,4′-dicarboxylic acid), have been hydrothermally synthesized and structurally characterized by elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analyses. Single-crystal X-ray analyses show that complexes 1–4 possess chain structures which are further assembled to form four three-dimensional (3-D) frameworks by π–π stacking and/or hydrogen-bonding interactions, while a similar chain of 5 has a two-dimensional (2-D) network packed by π–π stacking and hydrogen-bonding interactions. In 1–3, the Dpq ligand takes a chelating coordination mode while the other two nitrogen atoms did not coordinate to the Zn(II) ions. In 4 and 5, the Dpdq ligands have two coordination modes. The structural differences of the benzenedicarboxylate ligands and N-containing rigid/flexible chelating ligands have a great influence on the geometries of the corresponding complexes. This result also shows that intramolecular/intermolecular weak interactions play an important role in the formation of supramolecular networks, especially in linking low-dimensional entities into high-dimensional supramolecular frameworks. In addition, complexes 1 and 3–5 exhibit blue emission in the solid state at room temperature.

Fluorous Metal-Organic Frameworks with Enhanced Stability and High H2/CO2 Storage Capacities

A new class of metal-organic frameworks (MOFs) has been synthesized by ligand-functionalization strategy. Systematic studies of their adsorption properties were performed at low and high pressure. Importantly, when fluorine was introduced into the framework via the functionalization, both the framework stabilities and adsorption capacities towards H2/CO2 were enhanced significantly. This consequence can be well interpreted by theoretical studies of these MOFs structures. In addition, one of these MOFs TKL-107 was used to fabricate mixed matrix membranes, which exhibit great potential for the application of CO2 separation.

Zinc(II) coordination architectures with two bulky anthracene-based carboxylic ligands: crystal structures and luminescent properties

To systematically investigate the influence of ligands with a large conjugated π-system on the structures and properties of their complexes, we synthesized seven ZnII complexes with two anthracene-based carboxylic ligands, anthracene-9-carboxylic acid (HL1) and anthracene-9,10-dicarboxylic acid (H2L2), and sometimes incorporating different auxiliary ligands, {[Zn(L1)2(H2O)2](H2O)}∞ (1), [Zn5(μ3-OH)2(L1)8(2,2′-bipy)2] (2), Zn2(L1)4(phen)2(μ-H2O) (3), {[Zn(L1)2(4,4′-bipy)(CH3OH)2]}∞ (4), {[Zn(L2)2](Hdmpy)2(H2O)2}∞ (5), {[Zn2(L2)(2,2′-bipy)4](HL2)2}∞ (6) and {[Zn2(L2)(pypz)2(Hpypz)2]}∞ (7) (2,2′-bipy = 2,2′-bipyridine, phen = 1,10′-phenanthroline, Hpypz = 3-(2-pyridyl)pyrazole, 4,4′-bipy = 4,4′-bipyridine and Hdmpy = protonated 2,6-dimethylpyridine), which were characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. 1 has a one-dimensional (1-D) chain structure, whereas 2 exhibits a new pentanuclear cluster structure because of the introduction of a chelating 2,2′-bipy ligand. 3 and 4 take dinuclear and 1-D structures, respectively, by incorporating the auxiliary ligands phen and 4,4′-bipy. 5 is a three-dimensional (3-D) twofold interpenetrating diamondoid framework showing an open channel. 6 and 7 possess the corresponding chain structures containing Zn2 units as nodes by introducing Hpypz and 4,4′-bipy auxiliary ligands, respectively. These results indicate that the nature of ligands and auxiliary ligands has an important effect on the structural topologies of such complexes. Moreover, the luminescent properties of the corresponding complexes and ligands have been briefly investigated.

Single-crystal-to-single-crystal transformation in unusual three-dimensional manganese(II) frameworks exhibiting unprecedented topology and homospin ferrimagnet.

A new three-dimensional Mn(II) complex, [Mn(3)(HCO(2))(2)(L)(2)(OCH(3))(2)], 1 (L = nicotinate N-oxide), was synthesized by solvothermal reaction and magnetically characterized. Complex 1 exhibits an unprecedented 3,6-connected 5-nodal net topology with Schlafli notation {4(2);6}4{4(3)}2{4(6);6(6);8(3);10}2{4(8);6(6);8} and was assigned as a homospin ferrimagnet. Interestingly, when 1 was placed in air for ca. one month, the methoxy anions in 1 were gradually exchanged by hydroxyl anions and 1 underwent a single-crystal-to-single-crystal structural transition to a new but similar complex, [Mn(3)(HCO(2))(2)(L)(2)(OH)(2)] x 4 H(2)O, 2. The anion exchange and water molecules filling the channels of 2 affect the magnetic behavior at low temperature compared to that of 1.

Cadmium(II) and zinc(II) metal–organic frameworks with anthracene-based dicarboxylic ligands: solvothermal synthesis, crystal structures, and luminescent properties

Five new coordination polymers, namely, [Cd4(L11)2(DPP)2(DMF)2(SO4)2]∞ (1), [Zn2(L11)(DPP)2Cl2]∞ (2), [Cd(L222)(DPP)]∞ (3), [Zn(L222)(DPP)]∞ (4) and {[Cd2(L222)Cl4][(CH3)2NH2]2}∞ (5), (DPP = 1,3-di(4-pyridyl)propane and DMF = N,N-dimethylformamide), were prepared by solvothermal reactions of anthracene-9,10-dicarboxylic acid (H2L11) or anthracene-1,5-dicarboxylic acid (H2L222) with CdII or ZnII ions, and were structurally characterized by IR, elemental analysis, XRPD and single crystal X-ray diffraction. Complex 1 consists of a three-dimensional (3D) network with bcu (CsCl-type) topology assembled by pillar ligands L122−−, DPP and CdII ions and has one-dimensional (1D) channels running along the a-axis. In the case of complex 2, the CdII and SO42− ions are replaced by ZnII and Cl−, resulting in a 1D ladder chain. Complexes 3 and 4 are made up of longer pillars, H2L222 instead of H2L11, and have similar 3D four-fold interpenetrating diamond frameworks. And complex 5 forms a two-dimensional (2D) (32.62.72) kagome structure after taking out the longer pillar DPP. Moreover, the luminescence properties of all the complexes and the corresponding ligands in the solid state at room temperature have been investigated.

Tuning silver(I) coordination architectures by ligands design: from dinuclear, trinuclear, to 1D and 3D frameworks

In our efforts to tune the structures of AgI complexes by ligand modification, six structurally related ligands: 1,2-bis(triazol-1-ylmethyl)benzene (L1), 1,3-bis(triazol-1-ylmethyl)benzene (L2), 1,4-bis(triazol-1-ylmethyl)benzene (L3), 1,3,5-tri(triazol-1-ylmethyl)-2,4,6-trimethylbenzene (L4), 1,4-bis[3-(2-pyridyl)-pyrazol-1-ylmethyl]naphthalene (L5), and 9,10-bis(benzimidazol-1-ylmethyl)anthracene (L6) have been designed and used to react with AgI salts to form six new complexes: {[Ag2(L1)2](BF4)2(H2O)} (1), [Ag2(L2)(NO3)2]n (2), [Ag(L3)(NO3)]n (3), {[Ag3(L4)2](SiF6)1.5(H2O)3.5} (4), {[Ag2(L5)2](NO3)2(H2O)} (5), and {[Ag2(L6)2](NO3)2(CH3OH)2} (6). All the complexes have been structurally characterized by IR and X-ray diffraction. Structural analyses show that complexes 1, 5, and 6 possess dinuclear structures, which extend to infinite coordination networks linked by Ag⋯N, C–H⋯O, or π–π weak interactions. 2 is a 3D chiral coordination polymer with (10,3)-a topology, and 4 forms a trinuclear cage structure, which further connected by Ag⋯Ag weak interactions to form a 1D supramolecule, while 3 exhibits an infinite 1D chain structure. The structures of complexes 1–6 span from dinuclear, trinuclear, 1D, to 3D network, which indicates that ligands play important roles in the formation of such coordination architectures. Furthermore, the CD spectrum, thermal, and fluorescent properties of the chiral complex 2 have been investigated in the solid state.

Zinc(II) complexes with a versatile multitopic tetrazolate-based ligand showing various structures: impact of reaction conditions on the final product structures.

Four new zinc(II) complexes based on the same ligand, {Zn(ptp)(H(2)O)](2) (1), [Zn(ptp)(CH(3)OH)](n) (2), [Zn(ptp)](n) (3), and {[Zn(3)(ptp)(3)](DMF)(2)(H(2)O)}(n) (4) [H(2)ptp = 2,3-bis(pyridine-2-yl)-5,6-di-1H-tetrazol-5-ylpyrazine], have been synthesized by solvothermal methods. All of the complexes have been structurally characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analyses show that complex 1 possesses a centrosymmetrical neutral dinuclear structure and 2 has 1D right-handed helical chains, with the 2(1) axis expanding along the crystallographic b direction; 3 features a 2D chiral-layered structure with (6,3) net, and complex 4 displays a 3D porous framework with (4,12(2)) topology. The various architectures (0D, 1D, 2D, and 3D) of these four complexes indicated that reaction conditions (temperature and solvent) play an important role in the formation of such coordination structures; namely, various structures can be obtained from the same reactants by controlling and changing the reaction conditions in this system. The luminescent properties of all of the complexes and the corresponding ligand have been investigated in the solid state at room temperature. Moreover, adsorption properties (N(2), H(2), O(2), CO(2), and CH(4)) of the 4a (desolvated 4) have been studied, and the results show that 4a possesses a moderate capability of gas sorption for N(2), H(2), O(2), and CO(2) gases, with high selectivity ratios for O(2) over H(2) at 77 K and CO(2) over CH(4) at 273 K.

Template-directed synthesis of three new open-framework metal(II) oxalates using Co(III) complex as template

In our efforts to construct new metal–organic frameworks (MOFs) with open frameworks, three new metal oxalates, a 2D layered zinc oxalate [Co(en)3][Zn4(ox)7]0.5·5H2O (1), a 2D saw-tooth layered manganese oxalate [Co(dien)2][Mn4(ox)7]0.5·6H2O (2), and 3D open-framework cadmium oxalate [Co(dien)2][Cd4(H2O)2(ox)7]0.5·4.5H2O (3), have been synthesized under hydrothermal conditions by using Co(en)3Cl3 or Co(dien)2Cl3 as template. Compared to the previously reported oxalate compounds that possess only medium sized 12-ring channels, the three open-framework oxalates exhibit larger channels, 16- and 20-ring channels. Compound 1 is a layered structure with large elliptical 20-ring channels linked by ten ZnO6 and ten oxalates. Compound 2 exhibits a 2D saw-tooth sheet structure with 20-membered corrugated rings, and also presents an elliptical 16-ring aperture along [101] direction. Interestingly, compound 3 presents a 3D open framework, and Cd polyhedra and oxalate units alternate to form a 2D channel system that contains 12- and 20-ring channels, and it exhibits an unprecedented 3,4-connected mbc topology. Pairs of Co(III) complexes with opposite chirality are encapsulated inside the large channels as template. Our results suggest that using metal complexes as templates should be an effective strategy to construct MOFs.

Novel Ag(I) complexes with azole heterocycle ligands bearing acetic acid group: synthesis, characterization and crystal structures

Four novel AgI coordination complexes with azole heterocycle ligands bearing acetic acid group, [AgL1]n (1), [Ag(L2HL2)]n (2), [AgL3]n (3) and [Ag(L4)]n (4) (here, HL1 = 1H-imidazole-1-acetic acid, HL2 =1H-benzimidazole-1-acetic acid, HL3 =1H-1,2,4-triazole-1-acetic acid, HL4 =1H-benzotriazole-1-acetic acid), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Structural analyses show that complex 1 possesses a two-dimensional structure, which contains silver chains formed by weak Ag–Ag interactions, and 2 consists of neutral chains connected by weak bonds (O⋯H⋯O), while 3 and 4 have a three-dimensional network and a one-dimensional chain structure, respectively. It is interesting that in 1 there exist Ag–Ag interactions with a separation of 3.156 A, which play an important role in the formation of the complex. Furthermore, the conductivity of 1 was studied in the powder state.