Inclusion of quinolines by binaphthol: structures and selectivity

The enclathration selectivity of the host compound 2,2'-dihydroxyl-1,1'-binaphthyl, BINAP, towards the guests quinoline (Q), 2-methylquinoline (2MeQ), 6-methylquinoline (6MeQ) and 8-methylquinoline (8MeQ) were established by competition experiments as: BINAP.2(2MeQ) > BINAP.2Q > BINAP.2(8MeQ) > BINAP.2.5(6MeQ). The crystal structures of the inclusion compounds were elucidated and are all stabilised by (host)O-H...N(guest) hydrogen bonds. Thermal analysis yields the same sequence with respect to the relative stabilities. pH Control was employed to dramatically modify the selectivity profile of the pair of 2-methylquinoline (2MeQ) and 8-methylquinoline (8MeQ).     

Crystal Structures,Cytotoxicity, Cell Apoptosis Mechanism,and DNA Binding of Two 8-Hydroxylquinoline Zinc(II) Complexes

Two zinc(II) complexes, [Zn₄(HOQ)₆Ac₂] (I) (HOQ = 8-hydroxylquinoline) and [Zn₄(MeQ)₆Ac₂] (II) (MeQ = 2-methyl-8-hydroxylquinoline), were synthesized and characterized by IR spectroscopy, ESI-MS spectrometry, elemental analysis and single crystal X-ray diffraction analysis (CIF files CCDC nos. 1433544 (I) and 1433546 (II)). The in vitro cytotoxicity of the two complexes, which was first reported, was evaluated by MTT assay against a series of tumor cell lines as well as HL-7702 normal liver cell line. The results indicated that they showed significantly higher cytotoxicity than cispltain on BEL-7404 cells with IC₅₀ values of 11.85 ± 0.06 μM (I) and 8.40 ± 0.07 μM (II), respectively. Further apoptosis mechanism studies on BEL-7404 cells suggested that their antitumor activities were achieved through cell apoptosis and arrest at G1 or S phase. The decline of mitochondrial membrane potential, the elevation of reactive oxygen species and cytoplasmic calcium concentration ([Ca²⁺]_c), the raise of caspase-3/9 activity indicated that complexes I and II induced apoptosis of BEL-7404 by a mitochondrial dysfunction pathway. Investigations on the binding properties of complexes I and II to ct-DNA by UV-Vis, circular dichroism spectra and agarose gel electrophoresis indicated that the two complexes could bind with ct-DNA via an intercalative mode.     

Large Molecular Quadratic Hyperpolarizabilities in Donor/Acceptor-Substituted trans-Tetraammineruthenium(II) Complexes

A series of new Ru(II) complex salts trans-[Ru(NH(3))(4)(L(1))(L(2))](PF(6))(n) [n = 2, L(1) = 4-acetylpyridine (4-acpy) and L(2) = 4-(dimethylamino)pyridine (dmap) (1), 4-(dimethylamino)benzonitrile (dmabn) (2), 4-picoline (4-pic) (3), or 1-methylimidazole (1-MeIm) (4); n = 3, L(1) = N-methyl-4,4'-bipyridinium (MeQ(+)) and L(2) = dmap (6), dmabn (7), 1-MeIm (8), 4-acpy (9), or phenothiazine (PTZ) (10); n = 2, L(1) = dmap and L(2) = 4-pyridinecarboxaldehyde (pyca) (12) or ethyl isonicotinate (isne) (13)] have been synthesized and fully characterized. These complexes display intense, visible metal-to-ligand charge-transfer (MLCT) absorptions which are highly solvatochromic. An X-ray crystal structure determination has been carried out for trans-[Ru(NH(3))(4)(MeQ(+))(PTZ)](PF(6))(3).Me(2)CO (10.Me(2)CO). This salt, empirical formula C(26)H(38)F(18)N(7)OP(3)RuS, crystallizes in the hexagonal system, space group P6(3), with a = b = 17.853(4) ?, c = 21.514(6) ?, and Z = 6. The MeQ(+) ligand adopts an almost planar conformation, with a torsion angle of 9.6 degrees between the two pyridyl rings. The dipolar cations exhibit a strong projected component along the z axis, but crystal twinning precludes second-harmonic generation. Measurements of the first hyperpolarizability beta by using the hyper-Rayleigh scattering technique at 1064 nm yield very large values in the range (232-621) x 10(-30) esu, the largest being for trans-[Ru(NH(3))(4)(MeQ(+))(dmabn)](PF(6))(3) (7). These beta values are resonance enhanced via the MLCT excitations. A correlation between beta and the MLCT absorption energy confirms that this excitation is the primary contributor to beta. The two-level model yields static hyperpolarizabilities beta(0) in the range (10-130) x 10(-30) esu, with trans-[Ru(NH(3))(4)(MeQ(+))(dmap)](PF(6))(3) (6) having the largest. The beta(0) values of the complexes of the bipyridyl ligand MeQ(+) are larger than those of their analogues containing monopyridyl ligands because of extended conjugation. beta(0) correlates with the MLCT energy only when the MLCT absorption is sufficiently far from the second harmonic at 532 nm.     

两种部分甲基取代瓜环配合物的晶体结构(英文)

本文报道了2种新的部分甲基取代瓜环配合物的晶体结构,利用X-射线单晶衍射技术表征了2种配合物的结构,在CdCl2溶液中,1,2,4,5-八甲基六元瓜环选择性的包结客体分子1,2-(2,2′-bisbenzimidazolyl)ethanedichloride,形成2∶1的哑铃型主客体包结配合物;而1,2,4-六甲基五元瓜环(HMeQ[5])与钠离子配位形成包结一个水分子的"分子胶囊","分子胶囊"之间通过氢键自组装形成一维的超分子长链。     

Image analysis of the spatial distribution of paramagnetic Pr3+ ions in a polymer gel by a 1H-chemical shift NMR imaging method

¹H-chemical shift NMR imaging patterns of a poly(methacrylic acid) gel containing water with paramagnetic praseodymium ions(Pr³⁺) were successfully observed, in order to elucidate spatial distribution of Pr³⁺ ions in the gel. The ¹H chemical shift of water associated with Pr³⁺ ions in the gel moves largely downfield. By analyzing these experimental results, the immersion process of Pr³⁺ ions into the network of the polymer gel was spatially clarified. Further, it is shown that the chemical shift NMR imaging method is a useful means for determining the spatial distribution of paramagnetic metal ions in polymer gels.     

Rheological Degradation of Model Wax-Oil Gels

Paraffin gel formation in sub-sea petroleum transportation pipelines is a common problem encountered during operational and emergency production shut-down periods. Restart of a gelled oil pipeline usually requires the application of a large pressure drop across the pipeline length. In severe cases, permanent wax plugs have formed, resulting in the loss of production capacity. In this investigation, the structural breakdown of a quiescently-formed model wax-oil gel is measured at shear rates ranging from approximately 10^?5 sec^?1 to 1 sec^?1. It is demonstrated that gel breakdown can be mathematically modeled using a time-dependent Bingham equation in which the yield stress follows third order degradation kinetics. The Bingham plastic viscosity term becomes significant at shear rates above ～10^?1 sec^?1 and follows a similar third order decay profile with time. When the imposed shear rate is altered in a step-wise manner during the course of the gel breakage, transient non-linear viscoelastic effects are also observed in the mechanical stress response. Finally, explicit evidence is presented which indicates that after fracture, the gel strength behaves as a point function of the absolute strain, signifying a path-independent gel structure in terms of the single-dimensional flow history.     

N, C and Sn NMR and other spectroscopic studies of 8-quinolinol, its O- and N-methyl derivatives, and chelate di- and tri-organotin(IV) complexes

The nature of the 8-quinolinato ligand in various forms has been examined by ¹⁵N, ¹³C and ¹¹⁹Sn NMR spectroscopy, with evidence also from electronic spectroscopy. These forms include 8-quinolinol (HQ), 8-quinolinate, the 8-hydroxyquinolinium ion, O- and N-methyl derivatives, 8-methoxyquinoline (MeQ), the zwitterionic N-methylquinolinium-8-olate and the N-methylquinolinium ion, and the chelating ligand in organotin(IV) complexes. The ¹⁵N shift from MeQ to HQ affords a measure of the intramolecular hydrogen bonding in HQ. The ¹⁵N shifts and ²J(¹⁵N¹H) couplings afford criteria of chelation, and the O- and N-methyl compounds provide useful reference points for its assessment. Evidence for chelation is demonstrated in three groups of compounds, [SnR₂Q₂] (R = Me, Et, Buⁿ, Octⁿ or Ph), [SnR₃Q] (R = Me, Et, Buⁿ or Ph) and [SnR₂ClQ] (R = Me, Et, Buⁿ or Octⁿ), the ¹⁵N and ¹¹⁹Sn shielding increasing from the [SnR₃Q] to the [SnR₂Q₂] compounds.     

Effect of solvents on properties of polymer gel-electrolyte based on polyester diacrylate

New polymer gel electrolytes based on polyester diacrylates and LiClO₄ salt solutions in organic solvents are developed for lithium ion and lithium polymer batteries with a high ionic conductivity up to 2.7 × 10^?3 Ohm^?1cm^?1 at the room temperature. To choose the optimum liquid electrolyte composition, the dependence is studied of physico-chemical parameters of new gel electrolytes on the composition of the mixture of aprotic organic solvents: ethylene carbonate, propylene carbonate, and λ-butyrolacton. The bulk conductivity of gel electrolytes and exchange currents at the gel electrolyte/Li interface are studied using the electrochemical impedance method in symmetrical cells with two Li electrodes. The glass transition temperature and gel homogeneity are determined using the method of differential scanning calorimetry. It is found that the optimum mixture is that of propylene carbonate and λ-butyrolacton, in which a homogeneous polymer gel is formed in a wide temperature range of ?150 to +50°C.     

Specific stimuli‐responsive antipolyelectrolyte swelling of amphiphilic gel based on methacryloxyethyl dimethyloctane ammonium bromide

An amphiphilic electrolyte, methacryloxyethyl dimethyloctane ammonium bromide (MODAB), was synthesized by quaternization of dimethylaminoethyl methacrylate (DMAEMA) with 1‐bromooctane. Then amphiphilic PMODAB gel was synthesized by radiation cross‐linking with ethyleneglycol dimethacrylate as cross‐linker. PMODAB gels possess distinguished different swelling behaviors with those of DMAEMA hydrogels: (1) Antipolyelectrolyte phenomenon was observed in NaCl solution, that is, a remarkable increment of equilibrium degree of swelling (EDS) in the low NaCl concentration region (10^?4 to 10^?3 mol L^?1), followed by a significant decrease (10^?3 to 0.2 mol L^?1), and a collapsed state (>0.2 mol L^?1); (2) Compared with PDMAEMA, PMODAB was a temperature‐sensitive polymer which showed an upper critical solution temperature (UCST) behavior. The EDS of PMODAB gel dramatically increased at the UCST; (3) In the 0.2 mol L^?1 NaCl solutions, PMODAB gel swelled more significantly in a basic condition (pH > 10) than that in an acidic condition. The special volume phase transition behavior of PMODAB gel is ascribed to the hydrophobic interaction between octyl groups and the formation of ion‐cluster between tetra‐alkyl ammonium cation and Br^?, which lead to the aggregation of gel structure and could be affected by the composition and temperature of the surrounding solution. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 473–480, 2008     

Anion-Responsive Fluorescent Supramolecular Gels

Three novel bis-urea fluorescent low-molecular-weight gelators (LMWGs) based on the tetraethyl diphenylmethane spacer—namely, L1, L2, and L3, bearing indole, dansyl, and quinoline units as fluorogenic fragments, respectively, are able to form gel in different solvents. L2 and L3 gel in apolar solvents such as chlorobenzene and nitrobenzene. Gelator L1 is able to gel in the polar solvent mixture DMSO/H₂O (H₂O 15% v/v). This allowed the study of gel formation in the presence of anions as a third component. An interesting anion-dependent gel formation was observed with fluoride and benzoate inhibiting the gelation process and H₂PO₄⁻, thus causing a delay of 24 h in the gel formation. The interaction of L1 with the anions in solution was clarified by ¹H-NMR titrations and the differences in the cooperativity of the two types of NH H-bond donor groups (one indole NH and two urea NHs) on L1 when binding BzO⁻ or H₂PO₄⁻ were taken into account to explain the inhibition of the gelation in the presence of BzO⁻. DFT calculations corroborate this hypothesis and, more importantly, demonstrate considering a trimeric model of the L1 gel that BzO⁻ favours its disruption into monomers inhibiting the gel formation.     

Remarkable Reinforcement of a Supramolecular Gel Constructed by Heteroditopic [18]Crown‐6‐Based Molecular Recognition

The heteroditopic crown ether‐based ligand 1 containing the diazafluorenylimino group as a binding site for the Zn²⁺ and Cs⁺ was synthesized. The ligand 1 can be gelated in DMSO/water with and without Cs⁺ in the presence of the Zn²⁺ ion. Interestingly, the remarkable gelation reinforcement of gel 1 occurred with Cs⁺ in the presence of Zn²⁺, which is due to the formation of a sandwich complex. According to DFT calculations, one Zn²⁺ is bound to two diazafluorenylimino moieties in a tetrahedral structure. In addition, one Cs⁺ ion is bound to two crown‐rings. The Zn²⁺‐diazafluorenylimino ligand gel without Cs⁺ shows a spherical structure with 250–800 nm diameter, whereas the Zn²⁺‐diazafluorenylimino‐based ligand gel with Cs⁺ shows a fiber structure with 60–70 nm diameter and several micrometers of lengths. The rheological properties of the Zn²⁺‐ diazafluorenylimino‐based ligand gel were strongly dependent on the presence of Cs⁺.     

Preconcentration of palladium(II) from water with thionalide loaded on silica gel

2-Mercapto-N-2-naphthylacetamide (thionalide) on silica gel is used for rapid preconcentration of μg l^?1 levels of palladium(II) from aqueous solution, followed by atomic absorption spectrometric measurement. In batch experiments, palladium was quantitatively retained on the gel from solutions 5 M in acid to pH 8; equilibrium was achieved within 10 s. The chelating capacity of the gel was 7.5 μmol Pd g^?1 at pH < 4. The effect of flow rate on retention was studied. Palladium retained on the column was completely eluted with 20 ml of 0.2 M thiourea in 0.1 M hydrochloric acid. The palladium concentration in sea water is shown to be < 0.3 μg l^?1.     

Improved enzyme retention from an electropolymerized polypyrrole-alginate matrix in the development of biosensors

A novel pyrrole-alginate was synthesized providing a gel by Ca²⁺ cross-linking. The subsequent in situ electrochemical polymerization of the linked pyrrole groups at 0.93 V led to the formation of a composite polypyrrole–gel matrix exhibiting a greater enzyme retention as well as increased alginate stability towards the destructive effect of phosphate anions unlike the natural alginate gel. The presence of the electropolymerized chains was clearly indicated by the decrease of the permeability when compared to natural alginate gel, namely 2.7 × 10⁻² and 3.65 × 10⁻¹ cm s⁻¹ respectively, using as an electroactive permeate, hydroquinone. Moreover, the analytical performance of glucose oxidase-based composite alginate for the determination of glucose was determined.     

Differential preconcentration of arsenic(III) and arsenic(V) with thionalide loaded on silica gel

2-Mercapto-N-2-naphtylacetamide (thionalide) on silica gel is used for differential preconcentration of μg l^?1 levels of arsenic(III) and arsenic(V) from aqueous solution. In batch experiments, arsenic(III) was quantitatively retained on the gel from solutions of pH 6.5–8.5, but arsenic(V) and organic arsenic compounds were not retained. The chelating capacity of the gel was 5.6 μmol g^?1 As(III) at pH 7.0. Arsenic retained on teh column was completely eluted with 25 ml of 0.01 M sodium borate in 0.01 M sodium hydroxide containing 10 mg l^?1 iodine (pH 10). The arsenic was determined by silver diethyldithiocarbamate spectrophotometry. Arsenic(V) was subsequently determined after reduction to arsenic(III) with sulphite and iodide. Arsenic(III) and arsenic(V) in sea water are shown to be < 0.12 and 1.6 μg l^?1, respectively.     

二茂铁衍生物电子传递剂键合的溶胶-凝胶葡萄糖生物传感器

The sol-gel derived glucose biosensor was developed, and the sol-gel membrane was organically modified by N-（3-triethoxysilylpropyl）-ferrocenylmethylamine （FcSi） as sol-gel precursor to make electrochemical biosensor. The structure of biosensor was sol-gel/FcSi＋GOx/GC type （glucose oxidase, GOx）. The ferrocene mediator was chemically immobilized to the silane network, and GOx was entrapped to the sol-gel glass network. Therefore, these structures prevented mediator leakage and retained the enzyme activity. Additionally, pH of electrolyte, temperature effects, and interference of positive substances with biosensor were investigated. And the electrochemical performance of biosensor was studied by amperometry. The results indicated that the linear range, detection limit. and response slope of biosensor was 2.00×10^-4-1.57×10^-3 mol·L^-1, 2.0×10^-4 mol·L^-1 and 5.06×10^5 nA·mol^- 1·L, respectively.     

Self-Foaming Metal-Organic Gels Based on Phytic Acid and Their Mechanical,Moldable, and Load-Bearing Properties.

A catalogue of metal-organic gels are synthesized from phytic acid (PA) and a diversity of metal ions (Fe³⁺, Cr³⁺, Al³⁺, Ce³⁺, Y³⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Zn²⁺, Mg²⁺) upon heating at 80 °C. PA−M gels have various morphologies, including irregular granular (PA−Fe, PA−Al, PA−Ce, PA−Cr, PA−Ni, PA−Co), spongy (PA−Y), and hollow tremella-like (PA−Cu) morphologies. Interestingly for PA−Fe-1 : 4 (PA:Fe³⁺=1 : 4) a large amount of gas is generated during the gelation process leading to a self-foaming gel. The PA−Fe-1 : 4 self-foaming gel shows reversible gel-sol phase transition. The gel is unusually weakened and transformed into a sol at room temperature, and the sol is reversed to gelation when heated again at 80 °C. PA−Fe-1 : 4 gel also shows shapeable and load-bearing properties, and it can bear up to 200 times of its weight, depending on the gas amount fixed in the foam gel and the aging time. This work provides a catalogue of self-foaming supramolecular gels with tunable properties based on naturally abundant resources.     

基于NMR技术的溶菌酶在琼脂糖凝胶中的动力学研究

运用脉冲梯度场测量自扩散系数及自旋自旋弛豫时间测量核磁共振技术对鸡蛋清溶菌酶(HEWL)在琼脂糖凝胶中的动力学进行了研究.试验结果表明,HEWL在琼脂糖凝胶中的自扩散系数及自旋自旋弛豫时间较其在纯乙酸钠溶液中变小,说明琼脂糖凝胶的三维网状结构使HEWL分子整体运动及局部运动都受到阻碍.并且随着琼脂糖浓度的增大,凝胶网孔尺寸不断减小,HEWL分子运动受限程度加剧,从而蛋白质分子可以较长时间内停留在高浓度区,分子间更容易互相碰撞,发生反应,晶核生长得以促进.同时琼脂糖凝胶较小流体力学网孔尺寸抑制聚晶或沉淀的出现,晶体质量获得提高.     

Preliminary investigation of a new type of propylene based gel dosimeter (DEMBIG)

Radiotherapy widely uses the polymer gel dosimeter. The advantage of polymer gel dosimetry is the mapped 3D absorbed dose distribution that other dosimeters cannot achieve. The Acrylamide (AAm) is a frequently used monomer; however, the extreme toxicity of Acrylamide (ORL-RAT LD50: 124 mg/kg) raises a concern. Therefore, this study developed a new type of Propylene acid based gel dosimeter, named DEMBIG gel. The following outlines the aim of this study: (1) using two-point formulation to find the optimal scan parameter of MRI according to the best sensitivity and linearity (correlation coefficient) of DEMBIG gel, (2) using the optimal scan parameter of MRI to observe the properties of DEMBIG gel, and (3) verifying the three-dimensional (3D) dose distributions of radiotherapy. This study obtained three major results: 1. The scan protocol of MRI was established. 2. The preliminary results of DEMBIG gel were: (1) The range of absorbed dose of DEMBIG gel: 0–20 Gy. (2) The sensitivity and correlation coefficient of DEMBIG gel at verification as slope: 0.181 sGy^?1, R ²:0.997. (3) There is no energy dependency of the DEMBIG gel. 3. The dose difference was 3% in the three-dimensional (3D) isocenter dose in clinical radiotherapy. These data show that DEMBIG gel is a potential candidate for the 3D dosimeter.     

Development of an efficient protein phosphatase-based colorimetric test for okadaic acid detection

Okadaic acid (OA), responsible for gastrointestinal problems, inhibits protein phosphatase 2A (PP2A). Therefore, the inhibition exerted by the toxin on PP2A could be used to detect the presence of OA in aqueous solution and in shellfish sample.In this work, two commercial PP2As (from ZEU Immunotec and Millipore) and one produced by molecular engineering (from GTP Technology) were tested. Enzymes were used in solution and also immobilized within a polymeric gel. In solution, best performances were obtained using PP2A purchased from ZEU Immunotec (Spain). OA was detected in aqueous solution in concentration as low as 0.0124 μg L⁻¹ using the enzyme from ZEU Immunotec whereas the detection limits were 0.47 μg L⁻¹ and 0.123 μg L⁻¹ with PP2As from Millipore and GTP Technology, respectively. Considering that the immobilization step contributes to stabilize the PP2A activity, enzymes were entrapped within a photopolymer and an agarose gel. These different polymeric matrices were optimized, tested and compared. Agarose gel seems to be a good alternative to the photopolymer largely used in our group. For instance, the IC₅₀ value obtained with the test based on PP2A from ZEU Immunotec immobilized within an agarose gel was 1.98 μg L⁻¹. This value was 1.8-fold lower than those obtained with the photopolymer test using the same enzyme. The proposed test is sensitive, fast and does not require expensive equipment. To evaluate the efficiency of the assay, PP inhibition tests based on PP2A from ZEU Immunotec in solution or immobilized within a gel were used for OA detection in contaminated shellfish.     

Production of acetic acid by immobilized whole cells ofClostridium thermoaceticum

Immobilized cells ofClostridium thermoaceticum for acetic acid production has been investigated. Using κ-carrageenan gel as the immobilization-matrix, high cell concentration within the gel could be achieved and thus lead to high volumetric acetic acid productivity. Batch experiments using 3% gel showed that cell concentration up to 65 g (dry cell weight)/L gel could be achieved. These dry weight cell concentrations in the gel through immobilization are typically 10–15 times greater than what can be obtained in free-cell fermentations. The specific growth rate and acetic acid formation rate were similar to those observed for the free cells. Continuous culture experiments using a feed medium containing 20 g/L of glucose were performed where the reactor contained 50% by volume of the carrageenan gel and the pH was controlled at 6.9. Different steady states were acheived at dilution rates ranging from 0.061 to 0.399 h^?1. Cells grew mainly near the surface of the gel and reached maximum concentration within the matrix of approximately 35 g/L. Dilution rates much greater than the maximum specific growth rate were obtained, which resulted in volumetric productivity up to 4.9 g/L-h. This value was significantly greater than that for the conventional continuous culture with free cells. Using a 40 g/L feed glucose concentration, steady states could be achieved between dilution rates of 0.12–0.4 h^?1. The maximum productivity further increased to 6.9 g/L-h at a dilution rate of 0.37 h^?1 and at an acetic acid concentration of 19 g/L. The cell concentration was 60 g (dry weight)/L gel at steady state.