Lu-Fang Ma

Unprecedented 4- and 6-Connected 2D Coordination Networks Based on 44-Subnet Tectons, Showing Unusual Supramolecular Motifs of Rotaxane and Helix

Two unprecedented 2D coordination polymers with 4- and 6-connected topological nets, arising from the different linkages of two adjacent 4(4) layers, were prepared from Co(II), 1,3-bis(4-pyridyl)propane, and different isophthalate tectons.

MnII Coordination Polymers Based on Bi-, Tri-, and Tetranuclear and Polymeric Chain Building Units: Crystal Structures and Magnetic Properties

Five new Mn(II) coordination polymers, namely [Mn(2)(tbip)(2)(bix)] (1), [Mn(3)(tbip)(3)(bix)(2)] (2), [Mn(3)(tbip)(2)(Htbip)(2)(bib)(2)]·4H(2)O (3), [Mn(4)(tbip)(4)(bbp)(2)(H(2)O)(2)] (4), and [Mn(4)(tbip)(4)(bip)]·2H(2)O (5), were prepared by hydrothermal reactions of Mn(II) acetate with H(2)tbip (5-tert-butyl isophthalic acid) in the presence of different di-imidazolyl coligands (bix =1,4-bis(imidazol-1-ylmethyl)benzene, bib =1,4-bis(imidazol) butane, bbp =1,3-bis(benzimidazol)propane, bip =1,3-bis(imidazol)propane). All complexes were characterized by elemental analysis, IR spectra, thermogravimetric analysis, single-crystal X-ray crystallography, and powder X-ray diffraction. Single crystal X-ray studies show that these coordination polymers contain homometallic clusters varying from dimeric, trimeric, and tetrameric motifs to polymeric chains depending upon the coligands used. Complex 1 has a 3D 6-connected polycatenane network with dinuclear [Mn(2)O(2)] secondary building units. Complex 2 possesses a 3D 8-connected structure with trinuclear [Mn(3)(COO)(6)] units. Complex 3 shows a 3D pcu net based on trinuclear [Mn(3)(COO)(6)] clusters as nodes. Complex 4 features a 3D 8-connected structure constructed from the distorted square-grid tetranuclear [Mn(4)(μ(2)-COO)(8)(μ(2)-H(2)O)] units. Complex 5 shows a 3D (4,5,6)-connected net containing 1D μ-O/μ-COO alternately bridged chains. Magnetic susceptibility measurements indicate that complexes 1 and 3-5 show weak antiferromagnetic interactions between the adjacent Mn(II) ions, whereas 2 is a three-spin center homometallic ferromagnetic system.

Synthesis, structures and properties of Mn(II) coordination frameworks based on R-isophthalate (R = –CH3 or –C(CH3)3) and various dipyridyl-type co-ligands

Five new Mn(II) metal–organic coordination polymers, [Mn(tbip)(bipy)]n (1), {[Mn(tbip)(dpe)]·1.5H2O}n (2), [Mn(tbip)(bpa)]n (3), [Mn(mip)(bpa)]n (4) and {[Mn3(mip)2(Hmip)2(bpp)2(H2O)2]·2H2O}n (5), were prepared through hydrothermal reactions of Mn(II) acetate with H2tbip (H2tbip = 5-tert-butyl isophthalic acid) or H2mip (H2mip = 5-methylisophthalic acid) in the presence of different dipyridyl co-ligands (bipy = 4,4′-bipyridine, dpe = 1,2-bi(4-pyridyl)ethene, bpa = 1,2-bi(4-pyridyl)ethane and bpp = 1,3-di(4-pyridyl)propane). All these compounds were characterized by elemental analysis, IR spectroscopy and X-ray single-crystal diffraction. The structures of 1 and 2 are constructed of [Mn2(tbip)2]n layers, which consist of alternate left- and right-handed helical chains, and further pillared by bipy or dpe ligands into a 3D porous framework. Interestingly, there are two different sizes of pores in 1 and 2. From the topology point of view, both complexes 1 and 2 exhibit the rare rob network based on the dimeric [Mn(COO)]2 subunits as the 6-connected nodes. The ribbon-like chains having 8- and 16-membered rings in 3 and 4 result from dimeric Mn(II) units bridged by H2tbip or H2mip ligands, which are connected by the flexible dpa into 2D open layers. Complex 5 contains rare isophthalato-bridged trimanganese clusters as building units, which are further linked by mip anions to form a one-dimensional ladder-like chain with less common unidentate coordinated bpp decorated as pendants. The thermal stabilities and X-ray powder diffraction studies indicate that the microporous framework of 2 can keep stable even after the loss of guest water molecules. In addition, dominant antiferromagnetic coupling was observed in compounds 1–3 and 5.

Construction of Cd(II) coordination polymers based on R-isophthalate (R = –CH3 or –OCH3) and flexible N-donor co-ligands: Syntheses, structures and photoluminescence

Six new Cd(II) coordination polymers, namely, {[Cd2(CH3O-ip)2(1,3-btp)2(H2O)2]·7H2O}n (1), {[Cd(CH3O-ip)(1,3-bip)]·H2O}n (2), {[Cd(CH3O-ip)(1,4-btb)0.5(H2O)]·2H2O}n (3), {[Cd(CH3-ip)(1,3-btp)(H2O)]·H2O}n (4), {[Cd(CH3-ip)(1,6-bth)(H2O)]·H2O}n (5), {[Cd(CH3-ip)(1,4-btb)0.5(H2O)]·H2O}n (6) (CH3O–H2ip = 5-methoxyisophthalic acid, CH3–H2ip = 5-methylisophthalic acid, 1,3-btp = 1,3-bis(1,2,4-triazol-1-yl)propane, 1,3-bip = 1,3-bis(imidazol)propane, 1,4-btb = 1,4-bis(1,2,4-triazol-1-yl)butane, 1,6-bth = 1,6-bis(1,2,4-triazol-1-yl)hexane), were obtained under hydrothermal conditions. Complex 1 exhibits a 3-D supramolecular network constructed from a 2-D helical layer. Complex 2 has a (3,5)-connected 2-D layer with a (42·6)(42·67·8) topology. Complexes 3 and 6 feature a 3-D supramolecular structure constructed from (3,4)-connected 2-D layers with a (42·6)(42·63·8) topology. Complex 4 shows the interdigitation of 2-D nets between two puckered (4,4) sheets. Complex 5 possesses an extended 3-D supramolecular architecture based on 2-D (4,4) layers. Moreover, the photoluminescent properties and UV-vis absorption spectra of the six complexes were investigated.

Syntheses, structures and photoluminescence of five zinc(II) coordination polymers based on 5-methoxyisophthalate and flexible N-donor ancillary ligands

A series of zinc(II) coordination polymers with 5-methoxyisophthalate (CH3O–H2ip) and five related flexible N-donor ancillary ligands, [Zn(CH3O-ip)(bime)0.5] (1), [Zn(CH3O-ip)(btx)]2·H2O (2), [Zn(CH3O-ip)(bix)]2 (3), Zn(CH3O-ip)(bib) (4), [Zn2(CH3O-ip)2(bbim)]2 (5) [bime = 1,2-bis(imidazol-1′-yl)ethane, btx = 1,4-bis(triazol-1-ylmethyl)benzene), bix = 1,4-bis(imidazol-1-ylmethyl)benzene, bib = 1,4-bis(2-methyl-imidazol-1-yl)butane, bbim = 1,1′-(1,4-butanediyl)bis(benzimidazole)], have been synthesized under hydrothermal conditions. Complexes 1–5 were structurally characterized by elemental analysis, infrared spectra and X-ray single-crystal diffraction. These complexes display different types of entanglements. Complex 1 features an extended 3D polythreaded network based on 2D coordination frameworks with a (3,4)-connected (42.6)(42.63.8) topology. Complex 2 shows a rare example of entangled coordination polymer containing both interpenetrating and polythreading features. Complex 3 manifests a highly corrugated 2D (4,4) layer. The layers are penetrated by each other to give rise to 3D polycatenations. While 4 and 5 exhibit three-fold interpenetrated 3D 4-connected (65.8) and (3,4)-connected (42.6)(42.6.102.12) topologies, respectively. These results suggest that both 5-methoxyisophthalate and N-donor ancillary ligands influence on the final resulting structures. Furthermore, luminescent properties and thermogravimetric properties of these complexes were investigated.

Temperature and pH driven self-assembly of Zn(II) coordination polymers: crystal structures, supramolecular isomerism, and photoluminescence

Five Zn(II) coordination polymers, [Zn(mip)(btb)]·2H2O (1), [Zn2(mip)2(btb)1.5] (2), [Zn(moip)(btp)]·H2O (3), α-[Zn2(moip)2(btp)(H2O)2]·2H2O (4), β-[Zn2(moip)2(btp)(H2O)2]·2H2O (5), (H2mip = 5-methylisophthalic acid, H2moip = 5-methoxylisophthalic acid, btb = 1,4-bis(1,2,4-triazol-1-yl)butane, btp = 1,3-bis(1,2,4-triazol-1-yl)propane), have been obtained under hydrothermal conditions at 120 or 140 °C, respectively. Complexes 1 and 3 possess 3D supramolecular structures containing 1D tube-like chains. Complex 2 exhibits a (3,4,4)-connected trinodal 3D net with an unusual (6·82)(6·84·10)(6·85) topology. Complexes 4 and 5 are synthesized under similar conditions except for the pH values. Isomer 4 shows a 3D supramolecular network with a (82·10) topology. Isomer 5 features an extended 3D polythreaded network based on 2D bilayers, similar to that of 4. The construction of these complexes show that the temperature and pH value can modulate the resulting dimensionality and topology of the frameworks. Furthermore, the photoluminescence of complexes 1–5 has been investigated.

Dicarboxylate anion-dependent assembly of Ni(II) coordination polymers with 4,4′-dipyridyl sulfide

Four new coordination polymers, [Ni(isop)(bps)(H2O)]2n·5H2O (1), [Ni(O2N–BDC)(bps)(H2O)]2n (2), [Ni(OH–BDC)(bps)2(H2O)]n (3) and {[Ni2(H2O)(tbip)2(bps)2]}n (4) (bps = 4,4′-dipyridyl sulfide, H2isop= isophthalic acid, O2N–BDC = 5-nitroisophthalic acid, OH–BDC = 5-hydroxyisophthalic acid, H2tbip = 5-tert-butyl isophthalic acid), have been isolated from parallel hydrothermal reactions of Ni(OAc)2·4H2O and bps with isop, O2N–BDC, OH–BDC and H2tbip, respectively. Compound 1 is an unusual 2D double layered supramolecular motif generated by hydrogen bonding interactions of two single 2D (4,4) networks. Compound 2 has a highly puckered 2D (4,4) sheet and further stack viaO⋯O intermolecular contacts to form a 3D supramolecular structure. Compound 3 features a 2D rectangular grid layer with terminal bps ligands projecting into the interlayer space, leading to a highly interdigitated packing motif and further expansion to generate a 3-D network through interlayer C–H⋯π stacking interactions. Compound 4 contains [Ni2(H2O)]4+ dimers bridged by pairs of ligands into a single 3D diamond network with alternately left-handed and right-handed helical channels. As compared to isop, the coexistence of electron-donating (–OH, –C(CH3)3) or electron-withdrawing (–NO2) groups in the dicarboxylate derivatives has a significant effect on the molecular self-assembly. Variable-temperature magnetic susceptibility measurements reveals the existence of weak ferromagnetic interactions between the nickel centers in 4.

Delicate substituent effect of isophthalate tectons on the structural assembly of diverse 4-connected metal–organic frameworks (MOFs)

Assembly of isophthalate derivatives with ZnII in the presence of a flexible ligand 1,3-bis(4-pyridyl)propane yields distinct 4-connected coordination frameworks of sql (3.85)(32.83.9) and dia topologies, which reveal the delicate substituent effect of isophthalate tectons. The 3-D network in complex 2 is of 4-fold interpenetration with a new topology, displaying a unique polyrotaxane and polycatenane character.

Generation of a 4-crossing [2]-catenane motif by the 2D→2D parallel interpenetration of pairs of (4,4) sheets

A fascinating new series of structures in which 4-crossing [2]-catenane motifs are formed between pairs of interpenetrating 2D sheets; moreover, the inclined orientation of the two interpenetrating nets with a layer leads to the wrapping of helical chains of one net around zigzag chains of the other.

A novel 3D Mn(II) coordination polymer involving 4,4′-dipyridylsulfide and 4,4′-dipyridyltrisulfide obtained by in situ ligand formation from 4,4′-dipyridyldisulfide

A new coordination polymer, {[Mn(mip)(dps)](dpts)0.5}2n (1) (mip = 5-methylisophthalate) has been solvothermally synthesized by in situ generation of 4,4′-dipyridylsulfide (dps) and 4,4′-dipyridyltrisulfide (dpts) ligands from a 4,4′-dipyridyldisulfide (dpds) precursor. The coordination framework of 1 shows a new (3,5)-connected 3-D net topology with a Schlafli symbol of (42.65.83)(42.6), in which weak antiferromagnetic interactions are observed between the MnII ions.