5-(3',4'-Dicarboxylphenoxy)isophthalate/5-(2',3'-Dicarboxylphenoxy)isophthalate-Based 3D Cadmium(II) Coordination Polymers: Synthesis, Structure, and Sensing of Nitrobenzene.

5-(3',4'-Dicarboxylphenoxy)isophthalic acid (H4 L1) and 5-(2',3'-dicarboxylphenoxy)isophthalic acid (H4 L2) were reacted with Cd2+ salt with/without the assistance of N-donor ligands, creating five 3D CdII coordination polymers [Cd2 (L1)(H2 O)5 ]⋅H2 O (1), [Cd2 (L1)(bpe)(H2 O)] (bpe=1,2-bis(4-pyridyl)ethene; 2), [Cd2 (L1)(bpa)(H2 O)] (bpa=1,2-bis(4-pyridyl)ethane; 3), [Cd2 (L1)(bpp)] (bpp=1,3-bis(4-pyridyl)propane; 4), and [Cd2 (L2)(bpp)2 (H2 O)2 ]⋅H2 O (5). Crystal-structure analysis reveals 1) in 1, phthalate moieties for L1 link Cd1 centers into a 1D slightly helical chain; Cd2 centers act as bridges, linking 1D helical chains into a 3D network with a (3,5)-connected topology; 2) in 2-4, although Cd2+ centers were further modified by the introduction of organic bases, L1 molecules still link Cd2+ centers into 3D networks, which can all be simplified as pcu topology; 3) in 2-4, phthalate moieties first link Cd2+ centers into an oligomer, in which carboxylate-bridged discrete or rod-shaped secondary building units (SBUs) are found (tetranuclear SBU in 2 and 3, rod-shaped SBU in 4); and 4) in 5, L2 molecules link Cd2+ centers into a 2D (4,4) net; introduced bpp molecules serve as pillar linkers, extending Cd2+ -L2 layers into a 3D network of 5. The sensing abilities of 2-5 for nitrobenzene (NB) were investigated. Results revealed that they could all serve as fluorescence probes to sense NB at ppm concentrations.

Fluorescent metal-organic polymers of zinc and cadmium from hydrothermal in situ acylation reaction.

A series of metal-organic complexes based on d(10) metals and the ligand H(4)bbh (H(4)bbh = benzene-1, 2, 4, 5-biformhydrazide), formed through hydrothermal in situ acylate reaction of H(4)bta (H(4)bta = benzene-1, 2, 4, 5-tetracarboxylic acid) with hydrazine hydrate (N(2)H(4)·H(2)O), have been prepared and structurally characterized by single-crystal X-ray diffraction. Compounds [Zn(µ(2)-H(2)bbh)(phen)(H(2)O)](2) (1) (phen = 1, 10-phenanthroline) and [Zn(µ(2)-H(2)bbh)(2, 2'-bpy)](2) (2) (2, 2'-bpy = 2, 2'-bipyridine) are both dinuclear complexes in which bridging ligands H(2)bbh(2-) display different µ(2)- coordination modes. [Zn(µ(2)-H(2)bbh)(1/2)(µ(2)-H(2)bbh)(1/2)(H(2)O)](n) (3) exhibits a two-dimensional (2-D) layer structure containing simultaneously two kinds of different coordination modes of H(2)bbh(2-): µ(2)-bidentate and µ(4)-tetradentate. [Cd(µ(3)-H(2)bbh)(phen)](n) (4) consists of one-dimensional (1-D) double-metal chains. The crystal structures of these compounds are stabilized by hydrogen bonds and π···π interactions, forming three-dimensional supramolecular networks. All of the compounds were characterized by IR, UV-vis spectra and elemental analysis and they show good fluorescence properties in the solid state at room temperature. In order to understand the emission mechanism, we carried out TDDFT calculations on the excited electronic states of compound 2.

[Drug discovery based on classic natural products].

We think the strategy of classic natural product-based drug discovery will be an effective way for us to develop new drugs with independent intellectual property. The strategy includes: to study the molecular mechanism of action of classic natural product with chemical genetics and chemical biology approaches firstly; then establish the proper in vitro bioassay or bioassay system based on its molecular mechanism for their pharmacodynamic evaluation; finally, study their structure-activity, structure-toxicity and structure-ADME properties with medicinal chemistry.

Synthesis and characterization of binuclear molybdenum-polycarboxylate complexes with sulfur bridges.

A group of four binuclear sulfur-bridged molybdenum-polycarboxylato complexes with homocitrate, citrate, cysteine, ethylenediaminetetraacetate ligands, respectively, have been synthesized and characterized. These complexes were prepared in order to study the interaction of Mo and homocitrate in the FeMo-co of nitrogenases. In the structures of K4(NH4)2[Mo2O2S2(C6H4O7)2].10H2O (2), (NH4)2[Mo2O2S2(C3H5SNO2)2].5H2O (3) and (NH4)2[Mo2O2S2(C10H12N2O8)].3.5H2O (4), molybdenum (V) atom adopts a distorted octahedral arrangement through a terminal oxygen atom, two bridging sulfur atoms and three atoms from the ligand (hydroxyl, alpha-, beta-carboxylates, sulfide or amine). The coordination mode of homocitrate ligand in K5(NH4)[Mo2O2S2(C7H5O7)2].3H2O.CH3OH (1) has been proposed in a tridentate fashion via its hydroxyl and a pair of carboxylate groups (alpha-, beta-carboxylates). The electrochemical properties of these complexes have been discussed.