Diversity of complexes based on p-nitrobenzoylhydrazide, benzoylformic acid and diorganotin halides or oxides self-assemble: Cytotoxicity, the induction of apoptosis in cancer cells and DNA-binding properties.

Eight organotin(IV) complexes (C1-C8) have been synthesized and characterized by elemental analysis, fourier transform infrared spectroscopy (FT-IR), multinuclear nuclear magnetic resonance (1H, 13C and 119Sn NMR), high resolution mass spectroscopy (HRMS) and single crystal X-ray structural analysis. Crystallographic data show that C1 was a tetranuclear 16-membered macrocycle complex, C2-C4 and C7 were centrosymmetric dimer distannoxane and there was a Sn2O2 four-membered ring in the middle of the molecule, respectively, C5 and C6 are monoorganotin complexes due to the dehydroalkylation effect during the reaction, while C8 forms a one-dimensional chain structure. The cytotoxicity of all complexes were tested by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assays against three human tumor cell lines NCI-H460, MCF-7 and HepG2. The dibutyltin complex C2 has been shown to be more potent antitumor agents than other complexes and carboplatin. Cell apoptosis study of C2 with the high activity on HepG2 and MCF-7 cancer cell lines was investigated by flow cytometry, it was shown that the antitumor activity of C2 was related to apoptosis, but it has different cell cycle arrest characteristics from platinum compounds, and the proliferation was inhibited by blocking cells in S phase. The DNA binding activity of the C2 was studied by UV-visible absorption spectrometry, fluorescence competitive, viscosity measurements and gel electrophoresis, results shown C2 can be well embedded in the double helix of DNA and cleave DNA.

Bonding and Electronic Properties of Linear Diethynyl Oligothienoacene-Bridged Diruthenium Complexes and Their Oxidized Forms.

A series of five diruthenium diethynyl complexes based on α,ß-fused oligothienoacenes in the core of the bridging ligands [{Ru(dppe)Cp*}2(µ-C≡C-L-C≡C)] [dppe = 1,2-bis(diphenylphosphino)ethane, Cp* = η5-C5Me5; L = thieno[3,2-b]thiophene (4), thieno[2,3-b]thiophene (5), 3,4-dimethylthieno[2,3-b]thiophene (6), dithieno[3,2-b:2',3'-d]thiophene (7), and thieno[3,2-b]thieno[2',3':4,5]thieno[2,3-d]thiophene (8)] have been synthesized and fully characterized electrochemically and spectroscopically. Elongation of the redox noninnocent oligothienoacene bridge core causes a smaller potential difference between the initial two anodic steps, not seen for free dialkyl oligothienoacenes, and increased positive charge delocalization over the conjugated bridge backbone. The highest occupied molecular orbital of the parent complexes resides predominantly on the oligothienoacene core, with strong participation of the ethynyl linkers and slightly smaller contribution from the metallic termini. This bonding character makes the initial one-electron oxidation symmetrical, as revealed by combined voltammetric and spectroscopic (IR, UV-vis-near-IR, and electron paramagnetic resonance) methods as well as density functional theory (DFT) and time-dependent DFT calculations of truncated and selected nontruncated models of the studied series. The remarkable gradual appearance of two C≡C stretching absorptions in the IR spectra of the monocationic diethynyl complexes is ascribed to increasing vibronic coupling of the IR-forbidden νs(C≡C) mode of the oxidized -[C≡C-core-C≡C]+- bridge with a low-lying π-π*(intrabridge)/metal-to-ligand charge-transfer electronic transition in the near-to-mid-IR spectral region.

Triaqua-1κO,2κ(2)O-bis-(2,2'-bipyridine)-1κ(2)N,N';2κ(2)N,N'-chlorido-1κCl-µ-terephthalato-1:2κ(2)O(1):O(4)-dicopper(II) nitrate monohydrate.

In the binuclear title compound, [Cu(2)(C(8)H(4)O(4))Cl(C(10)H(8)N(2))(2)(H(2)O)(3)]NO(3)·H(2)O, the two crystallographically independent Cu(II) ions have similar coordination environments. One of the Cu(II) ions has a square-pyramidal arrangement, which is defined by a water mol-ecule occupying the apical position, with the equatorial ligators consisting of two N atoms from a 2,2'-bipyridine mol-ecule, one carboxyl-ate O atom from a terephthalate ligand and one O atom from a water mol-ecule. The other Cu(II) ion has a similar coordination environment, except that the apical position is occupied by a chloride ligand instead of a water mol-ecule. An O-H⋯O and O-H⋯Cl hydrogen-bonded three-dimensional network is formed between the components.

Dichlorido(4'-ferrocenyl-2,2':6',2''-terpyridine-κN,N',N'')zinc acetonitrile monosolvate.

The title complex, [FeZn(C(5)H(5))Cl(2)(C(20)H(14)N(3))]·CH(3)CN, is composed of one Zn(II) atom, one 4'-ferrocenyl-2,2':6',2''-terpyridine (fctpy) ligand, two Cl atoms and one acetonitrile solvent mol-ecule. The Zn(II) atom is five-coordinated in a trigonal-bipyramidal geometry by the tridentate chelating fctpy ligand and two Cl atoms.

Poly[[tetra-aquatetrakis-[µ(3)-5-(pyridine-4-carboxamido)-isophthalato]cobalt(II)digadolinium(III)] tetra-hydrate].

In the centrosymmetric polymeric title compound, {[CoGd(2)(C(14)H(8)N(2)O(5))(4)(H(2)O)(4)]·4H(2)O}(n), the Gd(III) cation is coordinated by one water mol-ecule and four pyridine-4-carboxamido-isophthalate (L) anions in a distorted square-anti-prismatic arrangement, while the Co(II) cation, located on an inversion center, is coordinated by two pyridyl-N atoms, two carboxyl-ate-O atoms and two water mol-ecules in a distorted octa-hedral geometry. The asymmetric unit contains two anionic L ligands: one bridges two Gd cations and one Co cation through two carboxyl groups and one pyridine-N atom; the other bridges two Gd cations and one Co cation through two carboxyl groups and the uncoordinated pyridine-N atom is hydrogen-bonded to the adjacent coordinated water mol-ecule. Extensive O-H⋯O and N-H⋯O hydrogen bonds are present in the crystal structure.

catena-Poly[[[diaqua-cadmium(II)]-bis-[µ-3,5-bis-(isonicotinamido)benzoato]] tetra-hydrate].

The title compound, {[Cd(C(19)H(13)N(4)O(4))(2)(H(2)O)(2)]·4H(2)O}(n) or {[Cd(BBA)(2)(H(2)O)(2)]·4H(2)O}(n), where BBA is 3,5-bis-(iso-nicotin-amido)-benzoate, is isotypic with its Mn isologue [Chen et al. (2009 ▶). J. Coord. Chem.62, 2421-2428]. The cation sits on a twofold axis and is six-coordinated in a slightly distorted octa-hedral geometry; the polyhedra are linked into zigzag chains, which are further connected by N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds as well as π-π inter-actions [centroid-centroid distance of 3.639 (2) Å], giving a three-dimensional supra-molecular framework.

K2S as Sulfur Source and DMSO as Carbon Source for the Synthesis of 2-Unsubstituted Benzothiazoles.

We describe a three-component reaction of o-iodoanilines with K2S and DMSO that provides 2-unsubstituted benzothiazoles in moderate to good isolated yields with good functional group tolerance. Electron-rich aromatic amines and o-phenylenediamines instead of o-iodoanilines provided 2-unsubstituted benzothiazoles and 2-unsubstituted benzimidazoles with and without K2S under similar conditions. Notably, DMSO plays three vital roles: carbon source, solvent, and oxidant.

(4'-Ferrocenyl-2,2':6',2''-terpyridine-κN,N,N)(1,10-phenanthroline-κN,N')zinc(II) bis-(perchlorate) acetonitrile monosolvate.

In the title complex, [FeZn(C(5)H(5))(C(20)H(14)N(3))(C(12)H(8)N(2))](ClO(4))(2)·CH(3)CN, the Zn(II) atom is five-coordinated by a tridentate chelating 4'-ferrocenyl-2,2':6',2''-terpyridine (fctpy) ligand and a bidentate chelating 1,10-phenanthroline (phen) ligand in a distorted square-pyramidal environment with a phen N atom located at the apical position [Zn-N = 2.259 (4) Å]. The terpyridyl motif in each fctpy ligand is coplanar, but the cyclo-penta-dienyl ring is twisted by 9.5 (2)° out of coplanarity with each central pyridine. The two cyclo-penta-dienyl rings of the ferrocenyl group are almost eclipsed with a deviation of 4.5 (1)°. In addition, inter-molecular π-π inter-actions [centroid-centroid distance 3.753 (2) Å] are present between the cyclo-penta-dienyl and outer pyridyl rings of the fctpy ligands. One of the perchlorate anions is equally disordered over two positions.

Poly[[[bis-(acetato-κO)copper(II)]-µ-1,4-diimidazol-1-ylbenzene-κN:N] dihydrate].

In the title linear coordination polymer, {[Cu(C(2)H(3)O(2))(2)(C(12)H(10)N(4))]·2H(2)O}(n), the Cu(II) atom is coordinated by two N atoms from two different symmetry-related 1,4-diimidazol-1-ylbenzene (dib) ligands and two carboxyl-ate O atoms from two acetate ligands in a square-planar geometry. The Cu atoms are linked by the dib ligands, forming an extended chain. These chains are linked by O-H⋯O hydrogen bonds into a three-dimensional supra-molecular network. The Cu(II) atom lies on a center of inversion.

(4'-Ferrocenyl-2,2':6',2''-terpyridine-κN,N',N'')(1,10-phenanthroline-κN,N')copper(II) bis(perchlorate) acetonitrile solvate.

The title complex, [CuFe(C(5)H(5))(C(20)H(14)N(3))(C(12)H(8)N(2))](ClO(4))(2)·C(2)H(3)N, consists of a mononuclear [Cu(C(12)H(8)N(2))(C(25)H(19)FeN(3))](2+) cation, two ClO(4) (-) anions (one of which is disordered over two positions with equal occupancy) and one CH(3)CN solvent mol-ecule. The Cu(II) center has a distorted square-pyramidal coordination with three N atoms of the 4'-ferrocenyl-2,2':6',2''- terpyridine (fctpy) ligand and one 1,10-phenanthroline (phen) N atom in the basal plane and a second phen N atom in the apical position with an axial distance of 2.254 (4) Å. The disordered ClO(4) (-) anion is weakly coordin-ated to the Cu(II) ion with a Cu-O distance of 2.766 (11) Å. The two cyclo-penta-dienyl rings of the ferrocenyl group are almost eclipsed with a deviation of 4.7 (1) °, and are involved in inter-molecular π-π inter-actions with the outer pyridyl rings of the fctpy ligands [centroid-centroid distance = 3.759 (2) Å.].

2,4,6-Tri-p-tolyl-pyridine.

In the title compound, C(26)H(23)N, the complete molecule is generated by crystallographic mirror symmetry, with the N atom and four C atoms lying on the reflection plane. The dihedral angles between the pyridine ring and pendant benzene rings are 2.9 (1), 14.1 (1) and 14.1 (1)°. Neighbouring mol-ecules are stabilized through inter-molecular π-π inter-actions along the c axis [centroid-to-centroid distance = 3.804 (2) Å], forming one-dimensional chains.

1-(2-Naphth-yl)-3-phenyl-prop-2-en-1-one.

The title compound, C(19)H(14)O, contains two independent mol-ecules with the same s-cis conformation for the ketone unit. Both mol-ecules are non-planar with dihedral angles of 51.9 (1) and 48.0 (1)° between the benzene ring and the naphthalene ring system. In the crystal, neighboring mol-ecules are stabilized by intermolecular C-H⋯π inter-actions, giving a two-dimensional supra-molecular array parallel to the ab plane.

3-[4-(Dimethyl-amino)phen-yl]-1-(2-pyrrol-yl)prop-2-en-1-one.

The molecule of the title compound, C(15)H(16)N(2)O, is non-planar with a dihedral angle of 16.0 (1)° between the pyrrole and benzene rings. The ketone double-bond displays an s-cis conformation with an O=C-C=C torsion angle of 7.9 (3) and an intramolecular C-H⋯O hydrogen bond. In the crystal structure, adjacent mol-ecules are paired through N-H⋯O hydrogen bonds into centrosymmetric dimers.

Selective adsorption of norfloxacin in aqueous media by an imprinted polymer based on hydrophobic and electrostatic interactions.

Based on hydrophobic and electrostatic interactions, a norfloxacin (NOF) imprinted polymer (P1) was prepared by the combined use of bismethacryloyl-beta-cyclodextrin (BMA-beta-CD) and 2-(diethylamino)ethylmethacrylate (DEAEM) as functional monomers. Compared with the molecularly imprinted polymers (MIPs) using only BMA-beta-CD or DEAEM as a functional monomer, P2 and P3, respectively, P1 showed higher binding affinity and specificity for NOF in aqueous media. Scatchard plot analysis revealed that two classes of binding sites were formed in the imprinted polymer with dissociation constants of 0.32 micromol/ml and 1.19 micromol/ml, respectively. It demonstrated that the combination of hydrophobic effect and electrostatic interaction in molecular imprinting was essential for the improvement of the selective ability of the imprinted polymer. Factors that influenced rebinding of the imprinted polymer including pH, water content in the adsorbed solution were explored.

[TDHF study of electronic absorption spectrum of (mu-L1) (mu-L2)-decacarbonyl triosmium].

Ab initio method was used to optimize the molecular geometry for a series of clusters (mu-L1) (mu-L2)- decacarbonyltri-osmium [L1, L2 = H, Cl, Br, I] at HF/CEP-4G level. The related chemical properties of clusters, in particular, the regularities of the bridge halogen effects on spectroscopic properties and bonding properties were discussed. The calculation results of the frontier molecular orbital showed that M-M bonds were mainly composed of s and d atomic orbitals. From Cl to I, with the atom number of bridge ligand increasing, HOMO and NHOMO orbitals on the Os3(CO)10 (mu-L)2 clusters and HOMO on the Os3 (CO)10 (mu-H) (mu-L) clusters become higher, while deltaepsilonL-H and deltaepsilon-NH energies become lower, so the authors predicted that the electronic absorption bands of clusters are shifted to infrared region. Excited states of clusters calculated with TDHF show that the transition of cluster Os3(CO)10 (mu-H)2 (I) is mainly 7 --> sigma* and sigma --> sigma*, while the electronic absorption of other clusters Os3 (CO)10 (mu-H) (mu-L) [L = Cl, Br, I] and Os3(CO)10 (mu-L)2 [-L = Cl, Br] is mainly from sigma --> sigma* transition. From Cl to I, with the atom number of bridge ligand increasing, the electronic absorption band of cluster is shifted to infrared region, and also the absorption becomes weaker.

Notable differences between oxidized diruthenium complexes bridged by four isomeric diethynyl benzodithiophene ligands.

Four new diruthenium complexes [{(η(5)-C5Me5)Ru(dppe)}2(µ-C[triple bond, length as m-dash]C-L-C[triple bond, length as m-dash]C)] featuring different bridging isomeric diethynyl benzodithiophenes viz. L = benzo[1,2-b;4,5-b']dithiophene (complex ), benzo[2,1-b;4,5-b']dithiophene (complex ), benzo[1,2-b;3,4-b']dithiophene (complex ) and benzo[1,2-b;4,3-b']dithiophene (complex ), were synthesized and characterized by molecular spectroscopic and crystallographic methods. The subtle changes in the molecular structure introduced by the diethynyl benzodithiophene isomers have a notable impact on the stability of the oxidized complexes and their absorption characteristics in the visible-NIR and IR spectral domains. Electronic properties of stable oxidized complexes [](n+) and [](n+) (n = 1, 2) were investigated by cyclic voltammetry, UV-vis-NIR and IR spectroelectrochemistry as well as DFT and TDDFT calculations. The results document the largely bridge-localized character of the oxidation of parents and . Cations [](+) and [](+) are too unstable at ambient temperature to afford their unambiguous characterization. UV-vis-NIR absorption spectral data combined with TDDFT calculations (BLYP35) reveal that the broad electronic absorption of [](+) and [](+) in the NIR region has a mixed intraligand π-π* and MLCT character, with similar contribution from their spin-delocalized trans and cis conformers. A spin-localized (mixed-valence) rotamer was only observed for [](+) at ambient temperature as a minor component on the time scale of IR spectroscopy.

[Theoretical calculation of vibrational frequencies for clusters of (1,2-micro2-L1)(1,2-micro2-L2)-decacarbonyltriosmium [L1, L2=H, Cl, Br, I]].

Density functional theory (DFT) and ab initio method have been employed to optimize the molecular geometry of (1,2-micro2-H) (1, 2-micro2-L) Os3 (CO)10 (L: Cl, Br, I) at B3LYP/CEP-4G, B3LYP/LanL2DZ, RHF/CEP-4G and RHF/LanL2DZ levels, respectively. By using ab initio method, the authors have optimized the molecular geometry of (1,2-t12 -L)2 Os3 (CO)20 (L: H, Cl, Br, I). The calculations showed that the charge was translated from Os(CO)3 to Os(CO)4. Harmonic vibrational analysis was performed at the RHF/CEP-4G levels, and according to the frequencies and intensities of the equilibrium structure obtained by using ab initio method, the IR spectra of structure have been simulated. The calculated results were compared with each other and with available experimental data, and were discussed in detail.

Preparation of 2D molecularly imprinted materials based on mesoporous silicas via click reaction.

The two-dimensional (2D) molecular imprinting approach has attracted extensive research interest in recent years due to its potential advantages such as simple construction, fast template removal and rapid mass transfer. In this study, a new 2D imprinting approach based on the combination of mesoporous silica materials and molecular imprinting technology is reported. 2D molecularly imprinted materials (MIMs) for cholesterol were prepared by using cholesterol as the template, azide modified ß-cyclodextrin (azide-ß-CD) as the functional monomer and alkynyl-modified SBA-15 (alkyne-SBA-15) as the skeleton. In this method, azide-ß-CD molecules were first assembled around the templates by formation of template-monomer complexes, and thus the mutual positions of azide-ß-CD molecules were fixed. Then, azide-ß-CD molecules were anchored to the walls of the nano-pores of SBA-15 via click chemistry. After removal of the template molecules, the resulting cavities, i.e., recognition sites were formed in the nano-pores of mesoporous silicas. The synthesized MIM was characterized by FT-IR, X-ray diffraction (XRD), elemental analysis (EA), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM) and so on. Binding kinetic experiments demonstrated that the 2D imprinting approach can improve site accessibility for the template effectively. The 2D MIM exhibited binding affinity and specificity for the template, as revealed by equilibrium binding experiments. When using MIM as a stationary phase for HPLC, baseline separation of cholesterol from other compounds can be achieved. In addition, the use of 2D imprinting significantly reduced the peak broadening and tailing.

Fluorogenic molecularly imprinted polymers with double recognition abilities synthesized via click chemistry.

This paper reports a new strategy for the preparation of molecularly imprinted polymer (MIP) based composite materials with double recognition abilities through the exploitation of click chemistry. Combining the inherent molecular recognition ability of MIPs and the affinity binding ability of boronic acid ligands for saccharides, a boronic acid-attached MIP with double recognition abilities was prepared. An alkyne modified 2,4-dichlorophenoxyacetic acid (2,4-D) imprinted polymer was first synthesized using a two-stage precipitation polymerization. An azide-contained boronic acid was then linked to the clickable 2,4-D imprinted polymers through copper-catalyzed azide-alkyne cycloaddition (CuAAC). The boronic acid-attached MIPs displayed recognition ability for 2,4-D and affinity binding ability for saccharides at physiological pH. The intensity of fluorescence emission of the boronic acid-attached MIPs was found to increase when increasing amounts of a cis-diol compound (i.e., fructose) were added.

Green synthesis of silver nanoparticles-graphene oxide nanocomposite and its application in electrochemical sensing of tryptophan.

A new kind of nanocomposite based on silver nanoparticles (AgNPs)/graphene oxide (GO) was conveniently achieved through a green and low-cost synthesis approach using glucose as a reducing and stabilizing agent, and the synthetic procedure can be easily used for the construction of a disposable electrochemical sensor on glassy carbon electrode (GCE). The nanocomposite was detailedly characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The experimental results demonstrated that the nanocomposite possessed the specific features of both silver nanoparticles and graphene, and the intrinsic high specific area and the fast electron transfer rate ascribed to the nanohybrid structure could improve its electrocatalytic performance greatly. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were employed to evaluate the electrochemical properties of AgNPs/GO/GCE towards tryptophan, and the AgNPs/GO film exhibited a distinctly higher activity for the electro-oxidation of tryptophan than GO film with tenfold enhancement of peak current. The oxidation mechanism and the kinetic parameters were investigated, and analysis operation conditions were optimized. Under the selected experimental conditions, the oxidation peak currents were proportional to tryptophan concentrations over the range of 0.01 µM to 50.0 µM and 50.0 µM to 800.0 µM, respectively. The detection limit was 2.0 nM (S/N=3). Moreover, the proposed method is free of interference from tyrosine and other coexisting species. The resulting sensor displays excellent repeatability and long-term stability; finally it was successfully applied to detect tryptophan in real samples with good recoveries, ranging from 99.0% to 103.0%.