Polyethylene glycol‐polyethylenimine‐tetrachloroplatinum (IV): A novel conjugate with good abilities of antitumor and gene delivery

It is much importance to develop novel multifunctional delivery systems for the combination therapy of drug and gene. In this work, a novel conjugate, polyethylene glycol‐polyethylenimine‐tetrachloroplatinum (IV) (PEG‐PEI‐Pt), with good abilities of antitumor and gene delivery was proposed by combining PEG (Mw 3400 Da), low molecular weight PEI (Mw 800 Da), and tetrachloroplatinum (IV). The antitumoral and gene transfection activities of PEG‐PEI‐Pt were analyzed in many tumor (A549, A375, HepG‐2, HuH‐7, and B16 cells) and normal (COS‐7 cells) cell lines. Similar to cisplatin (one platinum anticancer drug), PEG‐PEI‐Pt showed much higher sensitivity in tumor cells than in normal cells. More importantly, PEG‐PEI‐Pt had a potential to treat drug‐resistant tumors. Almost no transfection efficiency was observed for PEI (Mw 800 Da) and PEG‐PEI. Very interestingly, PEG‐PEI‐Pt could condense plasmid DNA efficiently, and exhibited good transfection efficiency in B16, HepG‐2, A375 and COS‐7 cells, comparable to even higher than PEI 25 kDa. In addition, PEG‐PEI‐Pt could also effectively deliver siRNA into the cytoplasm of tumor cells. With the good antitumoral and gene delivery abilities, PEG‐PEI‐Pt may have a great potential for combination therapy of drug and gene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and Biological Studies of Pyrazolyl‐Diamine PtII Complexes Containing Polyaromatic DNA‐Binding Groups

New [PtCl(pz*NN)]ⁿ⁺ complexes anchored by pyrazolyl‐diamine (pz*NN) ligands incorporating anthracenyl or acridine orange DNA‐binding groups have been synthesized so as to obtain compounds that would display synergistic effects between platination and intercalation of DNA. Study of their interaction with supercoiled DNA indicated that the anthracenyl‐containing complex L²Pt displays a covalent type of binding, whereas the acridine orange counterpart L³Pt shows a combination of intercalative and covalent binding modes with a strong contribution from the former. L²Pt showed a very strong cytotoxic effect on ovarian carcinoma cell lines A2780 and A2780cisR, which are, respectively, sensitive to and resistant to cisplatin. In these cell lines, L²Pt is nine to 27 times more cytotoxic than cisplatin. In the sensitive cell line, L³Pt showed a cytotoxic activity similar to that of cisplatin, but like L²Pt was able significantly to overcome cisplatin cross‐resistance. Cell‐uptake studies showed that L²Pt accumulates preferentially in the cytoplasm, whereas L³Pt reaches the cell nucleus more easily, as clearly visualized by time‐lapse confocal imaging of live A2870 cells. Altogether, these findings seem to indicate that interaction with biological targets other than DNA might be involved in the mechanism of action of L²Pt because this compound, despite having a weaker ability to target the cell nucleus than L³Pt , as well as an inferior DNA affinity, is nevertheless more cytotoxic. Furthermore, ultrastructural studies of A2870 cells exposed to L²Pt and L³Pt revealed that these complexes induce different alterations in cell morphology, thus indicating the involvement of different modes of action in cell death.     

Rhodium(I) complex catalyst immobilized on terpolymers of N‐vinylpyrrolidinone and 1‐vinylimidazole

The hydrosilylation of cyclohexanone and acetone with triethysilane and diphenysilane catalyzed by polymer‐supported Rh(I) complex has been investigated. Two terpolymers of styrene, divinylbenzene, and 1‐vinylimidazole (S/DVB/VI) or N‐vinylpyrrolidinone (S/DVB/NVP) were used as the catalysts supports. Physical characterization of these materials has involved the measurements of the structural parameters in the dry and swollen states by DSC, the nitrogen BET adsorption method and inverse steric exclusion chromatography ISEC. From these results it can be concluded that the original polymer structure has been changed during the complex attachment giving rise to materials of higher porosity. X‐ray photoelectron spectroscopy XPS, IR, and AAS spectroscopy were used to characterization of heterogeneous complexes before and after use. The effect of the morphology of the support on the catalytic properties of the polymer‐supported Rh(I) species was tested in the hydrosilylation of ketones and correlated with the reaction mechanism. It was demonstrated that the high selectivity of homogeneous rhodium complex toward the silyl ethers can be partially reversed to the dehydrogenative silylation products by a proper choice of polymer support with favorable microporous structure. Recycling tests demonstrated high stability of the supported catalysts during prolonged use. The constant selectivity of the supported catalysts demonstrated during recycling experiments showed that they could be useful for practical application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Theoretical Estimation of Acid Strength of Fluorine Hydrogen-Boron Fluoride Complexes

Abstract

The calculation of complexes R _n BF_3-n . HF (there is R = CH₃ and C₂H₅) has been carried out by the quantum-chemical semi-empirical MNDO method in Dewar and Teel parameterization. The geometrical and electronic structure of these complexes was obtained. On an example of simple H-acids we estimated their acid strength. We found that irrespective of the ligand surrounding of B atom the complexes R _n BF_3-n HF have rather high acid strength (pK _a = 17.9 14.9).     

Errors in the Calculation of 27Al Nuclear Magnetic Resonance Chemical Shifts

Computational chemistry is an important tool for signal assignment of ²⁷Al nuclear magnetic resonance spectra in order to elucidate the species of aluminum(III) in aqueous solutions. The accuracy of the popular theoretical models for computing the ²⁷Al chemical shifts was evaluated by comparing the calculated and experimental chemical shifts in more than one hundred aluminum(III) complexes. In order to differentiate the error due to the chemical shielding tensor calculation from that due to the inadequacy of the molecular geometry prediction, single-crystal X-ray diffraction determined structures were used to build the isolated molecule models for calculating the chemical shifts. The results were compared with those obtained using the calculated geometries at the B3LYP/6-31G(d) level. The isotropic chemical shielding constants computed at different levels have strong linear correlations even though the absolute values differ in tens of ppm. The root-mean-square difference between the experimental chemical shifts and the calculated values is approximately 5 ppm for the calculations based on the X-ray structures, but more than 10 ppm for the calculations based on the computed geometries. The result indicates that the popular theoretical models are adequate in calculating the chemical shifts while an accurate molecular geometry is more critical.     

Adsorption of As(III), As(V), Cd(II), Cu(II), and Pb(II) from Aqueous Solutions by Natural Muscovite

Various parameters were tested for the application of natural muscovite (NM) in the removal of metals from aqueous solutions: contact time, pH, ionic strength, and initial metal concentrations. Kinetic studies showed that the pseudo-second-order model explains well the sorption process. The adsorption of metals was greatly influenced by solution pH but not by ionic strength. The results from isotherm studies agreed more with the Freundlich isotherm model than with the Langmuir isotherm model. The adsorbed quantity of metals by NM was lower than that by the purified mica. These results suggested that the composition and surface characteristics of natural minerals may seriously influence applications for water purification.     

Preparation of the Sulfonamide Containing Block Copolymer as Polymeric Sorbent for Removal of Mercury from Aqueous Solutions

A new sulfonamide containing polymeric sorbent for the removal of mercury ions from waste waters was prepared starting from poly(glycidyl methacrylate)-b-poly(ethylene glycol)-b-poly(glycidyl methacrylate) (PGMA- b -PEG- b -PGMA) triblock copolymer prepared by using the ATRP method. Epoxy groups on the block copolymer were functionalized with amino groups. Ammonia-functionalized PGMA- b -PEG- b -PGMA was treated with excess of benzenesulfonyl chloride to obtain a sulfonamide-based polymeric sorbent. The sulfonamide containing the polymeric sorbent with a 3.5 mmol · g^?1 total nitrogen content is able to selectively sorb mercury from aqueous solutions. The mercury sorption capacity of the resin is around 3.12 mmol g^?1 under non-buffered conditions. Experiments performed in identical conditions with several metal ions revealed that Cd(II), Pb(II), Zn(II), Fe(III), and Fe(II) also were extractable in quantities (0–0.45 mmol/g). The sorbed mercury can be eluted by repeated treatment with 4 M HNO₃ without hydrolysis of the sulfonamide groups.     

通过磁矩判断配合物内外轨型的解题思路

通过磁矩判断配合物内外轨型是一类无机化学中的常见题目。首先通过磁矩推断出未成对电子数,然后根据核外电子的排布原则,结合中心原子（离子）在元素周期表中的位置,推断出配合物的内外轨型。     

The synthesis of tetrahedral bipyridyl metallo-octupoles with large second- and third-order nonlinear optical properties

Two new 4,4′-bis(donor)-6,6′-diphenyl- 2,2′-bipyridine ligands and their corresponding D_2d (Cu^I, Ag^I, Zn^II) octupolar metal complexes were synthesized, and their linear and nonlinear optical properties were investigated. A single crystal X-ray structure was also determined for the bis[4,4′-bis(diethylaminostyryl)-6,6′-diphenyl-bipyridine]copper(I) complex, which revealed a distorded pseudo-tetrahedral geometry. Molecular second-order nonlinear optical properties were determined for the complexes using the Harmonic Light Scatterring technique at 1.91 μm. These metallo-chromophores display large first hyperpolarizabilities β_1.91 in the range of 211-340 × 10⁻³⁰ esu, which increase with the Lewis acidity of the metal ion. The two-photon absorption properties of the bipyridyl ligands and related complexes were determined using either the two-photon emission method for fluorescent compounds or the open aperture Z-scan technique for non emissive ones. The complexes display red-shifted two-photon absorption bands compared to their metal-ion free chromophores, as well as a large increase of the maximum two-photon absorption cross-sections.     

Synthesis, characterization, and optical properties of new metal complexes with the multi-sulfur 1,2-dithiolene ligand

Metal complexes containing a new multi-sulfur atom containing 1,2-dithiolene ligand, [4′,5′:5,6] [1,4] dithiino[2,3-b] quinoxaline-1′,3′-dithiolate, have been synthesized and characterized by electrochemical measurements, IR, UV-NIR and ESR spectroscopies. X-ray structure analysis reveals that the anions of the Ni-complex derived from the new ligand form a zig-zag chain along the b axis, and the anions of Au complex of the ligand stack along the a axis while the cations occupy the holes. The Ni-complex exhibits remarkable absorption at 1082 nm (? = 15?000 dm³ mol⁻¹ cm⁻¹) and good solubility that render this complex as a promising near-IR dye for Q-switching neodymium lasers. The third-order non-linear optical properties of the complexes are measured by the Z-scan technique with a 6.5 ns pulsed laser at 532 nm. The Au complexes exhibit non-linear optical absorptive abilities, while the non-linear absorption of the nickel complex is negligible. All of the complexes show effective self-defocusing performance. The third-order non-linear optical susceptibilities for the Au complexes have been determined to be of the order of 10⁻¹³ esu.