Biomedical subjects
Publications and source records attributed to Zhong-Min Su.
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Rational self-assembly of a long V-shaped 3,3',4,4'-benzophenonetetracarboxylate (bptc) ligand and metal salts in the presence of linear bidentate ligand yield a series of novel pillared helical-layer complexes, namely, [Cu2(bptc)(bpy)2] (1), [M3(Hbptc)2(bpy)3(H2O)4].2 H2O (M = Fe(2) and Ni(3)), [Co2(bptc)(bpy)(H2O)].0.5 bpy (4), [Cd2(bptc)(bpy)(H2O)2].H2O (5), [Mn2(bptc)(bpy)1.5(H2O)3] (6) and [M2(bptc)(bpy)0.5(H2O)5].0.5 bpy (M = Mn(7), Mg(8) and Co(9), bpy=4,4'-bipyridine). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric (TG) analyses. The structure of 1 consists of two types of chiral layers, one left-handed and the other right-handed, which are connected by bpy pillars to generate a novel 3D open framework featuring four distinct helical chains. Compounds 2 and 3 are isostructural and feature 3D structures formed from the interconnection of arm-shaped helical layers with bpy pillars. Compound 4 is a pillared helical double-layer complex containing four different types of helices, among which the nine-fold interwoven helices constructed from triple-stranded helical motifs are unprecedented. Compound 5 exhibits a novel 3D covalent framework which features nanosized tubular channels. These channels are built from helical layers pillared by bptc ligands. The structure of 6 is constructed from {Mn(bptc)(H2O)}n2n- layers, which consist of left- and right-handed helical chains, pillared by [Mn2(bpy)3(H2O)4]4+ complexes into a 3D framework. To the best of our knowledge, compounds 1-6 are the first examples of pillared helical-layer coordination polymers. Compounds 7-9 are isostructural and exhibit interesting 2D helical double-layer structures, which are constructed from {M(bptc)(H2O)2}n2n- ribbons cross-linked by [M2(bpy)(H2O)6]4+ complexes. Furthermore, the 3D supramolecular structures of 7-9 are similar to the 3D structure of 6, and the 2D structure of 7 can be transformed into the 3D structure of 6 at higher reaction temperature. By inspection of the structures of 1-9, it is believed that the V-shaped bptc ligand and V-shaped phthalic group of the bptc ligand are important for the formation of the helical structures. The magnetic behavior of compounds 1, 2, 4, 6, and 9 was studied and indicated the existence of antiferromagnetic interactions. Moreover, compound 5 shows intense photoluminescence at room temperature.
The tetra-(8-hydroxyquinolinato) boron complex (Bq) and 3,3',4,4'-benzophenone tetracarboxylic anion (BPTC) were successfully intercalated into layered double hydroxides with an ion-exchange method. Elemental analyses, powder X-ray diffraction, FTIR spectra, and thermogravimetric analyses indicated that the hydrothermal treatment could efficiently improve the reaction process, the purity and crystallinity of products, and that Bq and BPTC molecules steadily arranged with C2 axis perpendicular to the layer plane, and the J-type aggregate in the host interlayer, respectively. The fluorescence studies showed that, compared with those observed in the dilute solutions of the guests, the spectra of Mg3Al-Bq and Mg3Al-BPTC evolved to the high-energy side and the low-energy side with increasing their loading, respectively, which were attributed to various arrangements of guests and the increased intermolecular interaction. Furthermore, their fluorescence intensity gradually decreased with increasing the intercalated guest content due to the concentration quenching, and Mg3Al-Bq exhibits enhanced solid-state blue luminescence due to a more rigid and constrained environment of the host.
An investigation of C(36)X(n) (X=F,Cl,Br; n=2,4,6,12) formed from the initial C(36) fullerene with D(6h) symmetry has been performed using the MP2 theory. Their equilibrium structures, reaction energies, strain energies, lowest unoccupied molecular orbital-highest occupied molecular orbital (LUMO-HOMO) gap energies, and aromaticities have been studied. The calculation results showed that those addition reaction were highly exothermic and C(36)X(n) were more stable than C(36). Moreover, from the view of thermodynamics it should be possible to detect C(36)X(6). The LUMO-HOMO gap energies of C(36)X(n) were higher than D(6h)C(36) and the redox characteristics of C(36)X(n) were weaker comparing to D(6h)C(36). The analyses of pi-orbital axis vector indicated that the chemical reactivity of C(36) was the result of the high strain, and the nucleus independent chemical shifts research showed that the stabilities of the C(36)X(6) were correlative with the conjugation effect.
To investigate the relationship between network connectivity and metal nuclearity, we designed and synthesized a series of three-dimensional (3D) entangled coordination frameworks based on different metal cores, namely [Zn(2)(bdc)(2)(L)(2)]2H(2)O (1), [Zn(bdc)(L)(0.5)] (2), [Zn(oba)(L)(0.5)] (3) and [Cd(3)(bdc)(3)(L)(2)(H(2)O)(2)] (4) by self-assembly of d(10) metal salts with the flexible long-chain ligand 1,4-bis(1,2,4-triazol-1-yl)butane (L), and with the rigid and nonrigid aromatic dicarboxylate ligands 1,4-benzenedicarboxylate (bdc) and 4,4'-oxybis(benzoate) (oba). Compound 1 exhibits a threefold interpenetrated diamondoid array typically based on a tetrahedral second building unit (SBU) at a single Zn center. Compound 2 adopts a threefold interpenetrated alpha-polonium-type network that is built from bimetallic cores as six-connected vertices. The structure of 3 also consists of dinuclear units; it comprises a novel (3,4)-connected threefold interpenetrated net with complex (4610)(46(2)10(3)) topology when single zinc centers act as four-connected nodes (or the alpha-Po topology if dinuclear units are considered as six-connected nodes). Compound 4, derived from a crosslinked fivefold interpenetrated diamond-like substructure, is an unusual example of a self-penetrating coordination framework displaying an unprecedented eight-connected 4(20)6(8) topology with trinuclear cadmium clusters as eight-connected nodes which, to our knowledge, not only defines a new topology for eight-connected coordination networks, but also represents the highest connected topology presently known for self-penetrating systems. Detailed structural comparison of these complexes indicates that the increase in metal nuclearity induces the progressive increase in the connectivities of the ultimate nets: that is, the metal nuclearity plays a significant role in tuning the connectivity of a specific network. The thermal and luminescent properties of these compounds are discussed.
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This article represents a systematical examination of the structures of silver(I) sulfonates incorporating neutral ligands. To survey the influence of the properties of neutral ligands on the structures of silver(I) sulfonates, three kinds of sulfonate anions (L1=1-naphthalenesulfonate, L2=p-toluenesulfonate, and L3=1, 3, 6, 8-pyrenetetrasulfonate) and three kinds of neutral ligands (pyrazine, Pyr, a divergent bidentate ligand; hexamethylenetetramine, hmt, a divergent tetradentate ligand; and beta-picoline, Pic, a monodentate ligand) were selected for study, and five novel silver(I) sulfonates containing neutral ligands have been synthesized: [Ag(L1)(Pyr)].H2O, Ag(L2)(Pyr), Ag4(L3)(Pyr)4(H2O)2, [Ag(L1)(hmt)].H2O, and Ag(L1)(Pic)2. The crystal structures have been determined by single-crystal X-ray diffraction, and these compounds show a variety of structures with different dimensionalities. Moreover, the luminescent properties of compounds and are also discussed.
Reactions of the antimicrobial fluoroquinolone ciprofloxacin (cfH) with metal salts in the presence of aromatic polycarboxylate ligands or under basic conditions produce fourteen new metal-cfH complexes, namely, [Ba2(cf)2(1,4-bdc)(H2O)2] x H2O (1), [Sr6(cf)6(1,4-bdc)3(H2O)6] x 2H2O (2), [M2(cfH)2(bptc)(H2O)2] x 8H2O (M = Mn3 and Cd4), [M(cfH)(1,3-bdc)] (M = Mn5, Co6, and Zn7), [Zn2(cfH)4(1,4-bdc)](1,4-bdc) x 13H2O (8), [Ca(cfH)2(1,2-Hbdc)2] x 2H2O (9) and [M(cf)2] x 2.5H2O (M = Mn10, Co11, Zn12, Cd13, and Mg14) (1,4-bdc = 1,4-benzenedicarboxylate, bptc = 3,3',4,4'-benzophenonetetracarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate, 1,2-bdc = 1,2-benzenedicarboxylate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The structures of 1 and 2 consist of unique two-dimensional arm-shaped layers. Compounds 3 and 4 are isostructural and feature one-dimensional structures formed from the interconnection of [M2(cfH)2(H2O)2] dimers with bptc ligands. Compounds 5-7 are isostructural and contain double-chain-like ribbons constructed from [M2(cfH)2(CO2)2] dimers and 1,3-bdc. Compound 8 consists of a pair of [Zn(cfH)2]2+ fragments bridged by a 1,4-bdc into a dinuclear dumbbell structure. Compound 9 is a neutral monomeric complex. To the best of our knowledge, compounds 1-9 are the first examples of metal-quinolone complexes that contain aromatic polycarboxylate ligands. Compounds 10-14 are isostructural and exhibit interesting two-dimensional rhombic grids featuring large cavities with dimensions of 13.6x13.6 A. Up to now, polymeric extended metal-cfH complexes have never been reported.
A novel cadmium(II) coordination polymer, poly[[[bis(4,4'-bipyridine)cadmium(II)]-mu(3)-4,4'-dicarboxybiphenyl-3,3'-dicarboxylato] 0.35-hydrate], {[Cd(C(16)H(8)O(8))(C(10)H(8)N(2))(2)].0.35H(2)O}(n), was obtained by reaction of Cd(CH(3)COO)(2).3H(2)O, 4,4'-bipyridine (4,4'-bpy) and biphenyl-3,3',4,4'-tetracarboxylic acid (H(4)L) under hydrothermal conditions. Each Cd(II) atom lies at the centre of a distorted octahedron, coordinated by four O atoms from three H(2)L(2-) ligands and N atoms from two monodentate 4,4'-bpy ligands. Each H(2)L(2-) ligand coordinates to three Cd(II) atoms through two carboxylate groups, one acting as a bridging bidentate ligand and the other in a chelating bidentate fashion. Two Cd atoms, two H(2)L(2-) anions and four 4,4'-bpy ligands form a ring dimer node, which links into an extended broad zonal one-dimensional chain along the c axis.
An unprecedented fivefold interpenetrated lvt network, containing the rare racemic motifs originated from nine interwoven helices, is reported, which represents the highest degree of interpenetration presently known for 3D nets containing only planar four-coordinate nodes.
The complexes of formulas Ln(pydc)(Hpydc) (Ln = Sm (1), Eu (2), Gd (3); H2pydc = pyridine-2,5-dicarboxylic acid) and Ln(pydc)(bc)(H2O) (Ln = Sm (4), Gd (5); Hbc = benzenecarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis, and single-crystal X-ray diffraction. Compounds 1-3 are isomorphous and crystallize in the orthorhombic system, space group Pbcn. Their final three-dimensional racemic frameworks can be considered as being constructed by helix-linked scalelike sheets. Compounds 4 and 5 are isostructural and crystallize in the monoclinic system, space group P2(1)/c. pydc ligands bridge dinuclear lanthanide centers to form the three-dimensional frameworks featuring hexagonal channels along the a-axis that are occupied by one-end-coordinated bc ligands. From the topological point of view, the five three-dimensional nets are binodal with six- and three-connected nodes, the former of which exhibit a rutile-related (4.6(2))(2)(4(2).6(9).8(4)) topology that is unprecedented within coordination frames, and the latter two species display a distorted rutile (4.6(2))(2)(4(2).6(10).8(3)) topology. Furthermore, the luminescent properties of 2 were studied.
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The first eight-connected self-penetrating metal-organic framework, based on pentanuclear zinc cluster building blocks, defines a new self-penetrating topology for eight-connected networks and represents the highest connected topology presently known for self-penetrating systems.
Two new three-dimensional nickel coordination polymers, [Ni3(BTC)2(4,4'-bpy)2(H2O)5].1.5H2O (1) and [Ni(PDB)(4,4'-bpy)].0.5H2O (2)(4,4'-bpy = bipyridine, BTC = 1,2,4-benzenetricarboxylate, PDB = pyridine-3,4-dicarboxylate), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TGA, and single crystal X-ray diffraction. Both compounds contain 2D scaffolding motifs, and most interestingly adjacent scaffolds are connected by infinite helical chains into unique three-dimensional mesomeric networks. Moreover, temperature-dependent magnetic susceptibilities for the two compounds were studied, and ferromagnetic interactions through syn-anti carboxylate bridges between Ni sites have been observed.
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