(E)-4-Fluoro-2-[(4-hy-droxy-pheneth-yl)imino-meth-yl]phenol.

The title compound, C(15)H(14)FNO(2), has an E conformation about the C=N bond, which facilitates the formation of an intra-molecular O-H⋯N hydrogen bond. The F atom is disordered over two adjacent sites in a 0.65 (7):0.35 (7) ratio. The dihedral angle between the benzene ring planes is 14.2 (2)°. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming C(14) [010] chains.

(E)-2-[(1-Benzyl-piperidin-4-yl)imino-meth-yl]phenol.

There are two mol-ecules in the asymmetric unit of the title compound, C(19)H(22)N(2)O. Both mol-ecules have an E conformation about their C=N bonds and both piperdine rings adopt chair conformations with their N atoms adopting pyramidal geometries [bond angle sums = 329.8 (4) and 330.2 (4)°]. Both mol-ecules feature an intra-molecular O-H⋯N hydrogen bond, which generates an S(6) ring. The dihedral angles between the phenyl and benzene ring planes are 45.97 (18) and 66.0 (2)°. Short O-H⋯O contacts occur in the crystal.

2-Fluoro-6-[(E)-(pyridin-2-yl)imino-meth-yl]phenol.

The title compound, C(12)H(9)FN(2)O, is almost planar (r.m.s. deviation for the 16 non-H atoms = 0.019 Å), a conformation stabilized by an intra-molecular O-H⋯N hydrogen bond, which generates an S(6) ring. In the crystal, inversion dimers linked by pairs of C-H⋯O hydrogen bonds generate R(2) (2)(16) loops.

Ethyl 4-[(E)-(2-hy-droxy-benzyl-idene)amino]-piperidine-1-carboxyl-ate.

In the title compound, C(15)H(20)N(2)O(3), the piperidine ring adopts a chair conformation, although the amide N atom is almost planar (bond angle sum = 359.7°). The mol-ecule adopts an E conformation about the C=N bond, which allows for the formation of an intra-molecular O-H⋯N hydrogen bond. In the crystal, mol-ecules are linked by C-H⋯O inter-ations, resulting in C(6) chains propagating in [010].

P6Mo18O73 heteropolyanion and its four-copper complex: theoretical and experimental investigation.

The non-classical KP(6)Mo(18)O(73) heteropolyanion has been studied by the density functional theory (DFT) method, and the calculated geometry compares well with the experimental one. In fully oxidized [KP(6)Mo(18)O(73)](7-) state, the d(xy)-orbitals centered at eight "belt" Mo sites in the lower part of the "basket" are the major contributors to the LUMO and LUMO+1, while the LUMO+2 orbital is mostly focused on the two polar parts. In contrast, the HOMOs indicates that the coordination of the KP(6)Mo(18) heteropolyanion to metal ions favorably occurs at the oxygen atoms from four external phosphates and two molybdates of the handle of the "basket". Compared with Wells-Dawson [P(2)Mo(18)O(62)](6-), the HOMO-LUMO gap in fully oxidized [KP(6)Mo(18)O(73)](7-) is much smaller, indicating much easier reduction that is consistent with the cyclic voltammogram. Both frontier orbitals and Mulliken analysis indicate that two of three blue electrons in [KP(6)Mo(18)O(73)](10-) (KP(6)Mo(18)-3e) have spin alpha while third blue electron has spin beta, in agreement with magnetic data. The four-copper complex of the non-classical KP(6)Mo(18)-3e heteropolyanion has been synthesized and structurally characterized; its structure supports the theoretical results such as reactivity and basicity of external oxygen sites.

Design and synthesis of potent inhibitors of beta-ketoacyl-acyl carrier protein synthase III (FabH) as potential antibacterial agents.

Twenty new Schiff bases were synthesized by reacting 5-fluoro-salicylaldehyde and primary amine as potent inhibitors of FabH. These compounds were assayed for antibacterial activity against Escherichia coli, Pseudomonas fluorescence, Bacillus subtilis and Staphylococcus aureus. Compounds with potent antibacterial activities were tested for their E. coli FabH inhibitory activity. (E)-4-fluoro-2-((4-hydroxyphenethylimino)methyl)phenol (10) showed the most potent antibacterial activity with MIC of 1.56-6.25 microg/mL against the tested bacterial strains and exhibited the most potent E. coli FabH inhibitory activity with IC(50) of 2.7 microM. Docking simulation was performed to position compound 10 into the E. coli FabH active site to determine the probable binding conformation.

Synthesis, structure and structure-activity relationship analysis of caffeic acid amides as potential antimicrobials.

A series of caffeic acid amides 1-23 were synthesized and nine of which (13-17, 19-21 and 23) were reported for the first time. The chemical structures of these compounds were confirmed by means of 1H NMR, ESI MS and elemental analyses. Compound 15 was determined by single-crystal X-ray diffraction analysis. All of the compounds were assayed for antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens and Staphylococcus aureus) and antifungal (Aspergillus niger, Candida albicans and Trichophyton rubrum) activities by MTT method. Compounds 10-12, 15, 18 and 21 showed considerable antibacterial activities against B. subtilis with MICs of 7.95, 6.25, 3.89, 1.18, 3.12 and 15.5 microg/mL, respectively. Structure-activity relationship analysis disclosed that caffeic acid anilides with electron-donating groups at p-position of benzene ring have better inhibitory activities.

Synthesis, characterization and structure-activity relationship analysis of novel depsides as potential antibacterials.

Twenty-six depsides were synthesized to screen for their antibacterial activity. All of them were reported for the first time. Their chemical structures were clearly determined by (1)H NMR, (13)C NMR, ESI mass spectra and elemental analyses, coupled with one selected single-crystal structure. All the compounds were assayed for antibacterial activities against three gram-positive bacterial strains (Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538 and Streptococcus faecalis ATCC 9790) and three gram-negative bacterial strains (Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 13525 and Enterobacter cloacae ATCC 13047) by MTT method. Compound 2-(2-methoxy-2-oxoethyl)phenyl 3-nitrobenzoate (C10) and 2-(2-ethoxy-2-oxoethyl)phenyl 3-nitrobenzoate (C23) showed powerful antibacterial activities against B. subtilis with MIC of 0.78 microg/mL while compound 2-(2-methoxy-2-oxoethyl)phenyl 2-(3,4-diethoxyphenyl)acetate (C8) and 2-(2-ethoxy-2-oxoethyl)phenyl 2-(3,4-diethoxyphenyl)acetate (C21) exhibited significant antibacterial activities against E. coli with MIC of 1.562 microg/mL, which were superior to the positive controls penicillin G and kanamycin B, respectively. On the basis of the biological results, structure-activity relationships were discussed.

Cu6S4 cluster based twelve-connected face-centered cubic and Cu19I4S12 cluster based fourteen-connected body-centered cubic topological coordination polymers.

Hydrothermal reaction of Cu(MeCO2)2, (4-pyridylthio)acetic acid and NH4SCN resulted in a twelve-connected face-centered cubic topological metal-organic framework [Cu3(pdt)2(CN)] (pdt = pyridinethiolate) in which Cu6S4 clusters act as twelve-connected nodes and pyridine rings and cyanides act as connectors. As an extension, an unprecedented fourteen-connected body-centered cubic coordination polymer [Cu19I4(pdt)12(SH)3] has been synthesized by three methods, in which nanosized chiral Cu19I4S12 clusters act as fourteen-connected nodes and triple pyridine rings and hydrosulfides act as connectors. The in situ S-C(sp(3)), S-C(sp(2)), and S-C(sp) cleavage reactions have been observed in the work.

Enamines as novel antibacterials and their structure-activity relationships.

Twenty-six enamines were synthesized to screen for the antimicrobial activity. Out of the compounds, 22 were reported for the first time. Their chemical structures including E/Z-configurations were clearly determined by 1H NMR, ESI mass spectra and elemental analyses, coupled with three selected single-crystal structures. In general, these synthetic compounds were shown to be more effective to inhibit growth of bacteria than fungi. The most active compound, (E)-ethyl 3-(4-hydroxyphenylamino)-2-(4-chlorophenyl)acrylate (1b), showed considerable antibacterial activities against Staphylococcus aureus ATCC 6538 with MIC of 0.5 microg/mL and against Pseudomonas fluorescens ATCC 13525 with MIC of 1.5 microg/mL, which was superior to the positive controls penicillin and kanamycin, respectively. Structure-activity relationship analysis revealed: as for A-ring, the compounds substituted at 3,5-positions were more active than 2,4-position-substituted derivatives, and halo-substituted analogs at 2-position had essentially same activities as the 4-position-substituted derivatives. Increase of steric hindrance around the nitrogen atom led to an inactive compound.

A novel heterocyclic compound: catena-poly[[[diaquasodium(I)]-di-mu-aqua] hemi(1,5-dihydroxy-4,8,9-trioxa-2,6-diazabicyclo[3.3.1]nona-2,6-diene-3,7-diolate)].

In the title compound, {[Na(H2O)4]2(C(4)H(2)N(2)O(7))}n, the 1,5-dihydroxy-4,8,9-trioxa-2,6-diazabicyclo[3.3.1]nona-2,6-diene-3,7-diolate anion lies across a twofold axis in the space group C2/c; there are two independent Na sites, one on a twofold axis and the other on a centre of inversion. Hydrogen bonds link the {[Na(H2O)4]+}n chains and diolate anions into a three-dimensional framework.

Diversity of coordination architecture of metal 4,5-dicarboxyimidazole.

Seven complexes of metal 4,5-dicarboxyimidazole acid (H3dcbi), namely, [Cd(H2dcbi)2(H2O)3].H2O (1.alpha), [Cd(H2dcbi)2(H2O)2].2H2O (1.beta), [Cd(H2dcbi)2(H2O)2].2H2O (1.gamma), [Cd(H2dcbi)2(H2O)2] (2), [Cd(Hdcbi)(H2O)] (3), [Cd5(Hdcbi)2(dcbi)2(H2O)].XH2O (4), [Cd2(Hdcbi)(C2O4)] (5), [Ag5(Hdcbi)2(CN)] (6), and [Mn(Hdcbi)(H2O)] (7), have been hydro(solvo)thermally synthesized by fine control over synthetic conditions such as stoichiometry, solvent, and pH value. X-ray single-crystal structural analyses reveal that they have rich structural chemistry ranging from mononuclear (1), one-dimensional (2), and two-dimensional (3 and 7) to three-dimensional (4-6), among which 1 crystallizes in three types (alpha, beta, and gamma) of polymorphs. Seven coordination modes of H(n)dcbi ranging from monodentate to mu5 have been observed, among which four modes are found first. The coordination geometries of the Cd(II) sites vary from five-coordinate trigonal bipyramid and square pyramid, six-coordinate octahedron to seven-coordinate pentagonal bipyramid. Analyses of the synthetic conditions and structures of the Cd(II) complexes show that the influences of the solvent and the metal-to-ligand molar ratio are very important to the products and coordination modes of H(n)dcbi (n =0, 1, 2). Studies of the coordination modes of H(n)dcbi and the structures of the Cd(II) complexes also reveal that the singly deprotonated H2dcbi generally coordinates in the monodentate imidazole-N or N,O-chelate mode to result in mononuclear structures, the doubly deprotonated Hdcbi coordinates in the mu2, mu3, or mu4 mode to generate one-dimensional or two-dimensional structures, and the triply deprotonated dcbi can coordinate in the mu5 mode to form three-dimensional structures. The cyanide was in situ formed via C-C bond cleavage of acetonitrile during the preparation of 6, which adopts a rare mu4-kC,kC:kN,kN mode to bridge four Ag(I) ions. The microporous three-dimensional framework of 4 is maintained after the removal of the guest molecules. Compounds 1-5 show strong violet emissions with maxima around 380 nm, tentatively attributed to the ligand-centered transition.

A twelve-connected Cu6S4 cluster-based coordination polymer.

Hydrothermal reaction of Cu(MeCO2)2, (4-pyridylthio)acetic acid, and NH4SCN resulted in a metal-organic framework [Cu3(4-pyridinethiolate)2(CN)] which has twelve-connected face-centered cubic topology with Cu6S4 clusters as nodes.

Hydrothermal syntheses and structures of two mixed-valence copper(I,II) 2-pyrazinecarboxylate coordination polymers.

Replacement of linear ligand L in Cu(I)XL system (X = halide or pseudohalide; L = 4,4'-bipyridine or pyrazine) by neutral species Cu(pzc)2(H2O)x (pzc = 2-pyrazinecarboxylate) resulted in mixed-valence Cu(I,II) coordination polymers [Cu2(pzc)2Br(H2O)]n (1) and [Cu3(pzc)2(CN)2(H2O)2 x 2H2O]n (2). Complex 1 has two-dimensional (4,4) topological layer constructed by [CuBr]n chains and Cu(pzc)2(H2O) species, while 2 has a three-dimensional framework formed by linkage of two-dimensional (6,3) layers via ligand-unsupported Cu(I)-Cu(I) interactions. The two-dimensional (6,3) layer in 2 is constructed by zigzag [CuCN]n chains and Cu(pzc)2(H2O)2 species. Cyanides in 2 were produced by oxidative desulfation of SCN- anions.