A doubly charged metal dication complexes [Mn(Pyridine)4]2+ ions were formed and further activated with methane in the gas phase. [Mn(Pyridine)CH4]2+, [Mn(Pyridine)2CH4]2+, [Mn(Pyridine)3CH4]2+, [MnPy2Me2]2+ [MnPy3Me2]2+ and [Mn(Pyridine)4CH4]2+ were successfully identified after the experimental analysis. The average pyridine binding energy, calculated at the different levels of theory of zero point energy are in realistic agreement. The binding energies of methane decrease drastically with increasing number of pyridine ligands in the order of [Mn(Pyridine)CH4]2+>[Mn(Pyridine)2CH4]2+>[Mn(Pyridine)3CH4]2+> [Mn(Pyridine)4CH4]2+. The optimised structure of [Mn(Pyridine)4(CH4)]2+ indicated C1 symmetry with the methane-manganese ion distance approximately r=2.00 Å. DFT calculated binding energy of methane with Mn2+ was 15.13 kJ/mol while the binding energy calculated on the potential energy curve (PEC) was 17.37 kJ/mol. This higher interaction energy calculated from the PEC was due to the fact that the charge +2 was assumed for the metal ion in the calculations, but at the optimised geometry the DFT calculated actual charge on the metal ion was (Z=1.43). The calculated binding energy of methane with manganese pyridine dication complex ion was drastically overestimated on the PEC by approximately 15% compare to DFT.

Photofragmentation with tunable UV radiation has been used to generate a spectrum for the copper-bis(benzene) complex, [Cu(C6H6)2](2+), in the gas phase. The ions were held in an ion trap where their temperature was reduced to ∼150 K, whereby the spectrum revealed two broad features at ∼38,200 and ∼45,700 cm(-1). Detailed calculations using density functional theory (DFT) show the complex can occupy three minimum energy structures with C2v and C2 (staggered and eclipsed) symmetries. Adiabatic time-dependent DFT (TDDFT) has been used to identify electronic transitions in [Cu(benzene)2](2+), and the calculations show these to fall into two groups that are in excellent agreement with the experimental data. However, the open-shell electronic configuration of Cu(2+) (d(9)) may give rise to excited states with double-excitation character, and the single-excitation adiabatic TDDFT treatment leads to extensive spin contamination. By quantifying the extent of spin contamination and allowing for the inclusion of a small percentage (∼10%), the theory can provide quantitative agreement with the experimental data.

Toxic heavy metals, such as Pb(2+), have become important targets for the development of efficient receptors that are capable of recognizing their presence as environmental and biological pollutants, and an important part of that receptor-metal characterization process is the provision of spectral evidence that identifies the presence of a metal ion. From results reported here on a combined experimental and theoretical study it is shown that, when complexed with aromatic ligands, Pb(2+) is capable of yielding structured UV spectra, which: (i) exhibit discrete electronic transitions that include significant contributions from the metal ion; (ii) are very sensitive to the electronic properties of coordinating ligands; and (iii) are sensitive to subtle changes in coordination geometry. Two aromatic sandwich complexes, [Pb(benzene)2](2+) and [Pb(toluene)2](2+) have been prepared in the gas phase and their UV action spectra recorded from ions held and cooled in an ion trap. Whilst [Pb(benzene)2](2+) exhibits a spectrum with very little detail, that recorded for [Pb(toluene)2](2+) reveals a rich structure in the wavelength range 220-280 nm. Theory in the form of density functional theory (DFT) shows that both types of complex take the form of hemidirected structures, and that [Pb(toluene)2](2+) can adopt three distinct conformers depending upon the relative positions of the two methyl groups. Further calculations, using adiabatic time-dependent DFT to assign electronic transitions, provide evidence of individual [Pb(toluene)2](2+) conformers having been resolved in the experimental spectrum. Of particular significance for the development of methods for identifying Pb(2+) as an environmental or biological pollutant, is the observation that there are distinct ligand-to-metal charge transfer transitions in the UV that are sensitive to both the geometry and the electronic characteristics of molecules that accommodate the metal ion.

The copolymerization of styrene with ethylene was promoted by CpTiCl3/BDGE/Zn/MAO catalyst system combining free radical polymerization with coordination polymerization via sequential monomer addition strategy in one-pot. The effect of polymerization conditions such as temperature, time, ethylene pressure, and Al/Ti molar ratio on the polymerization performance was investigated. The hydroxy-functionalized aPS-b-random copolymer-b-PE triblock copolymer was obtained by solvent extraction and determined by GPC, DSC, WAXD, and C-13-NMR. The DSC result indicated that the aPS-b-random copolymer-b-PE had a T-g at 87 degrees C and a T-m at 119 degrees C which attributed to the T-g of aPS segment and the T-m of PE segment, respectively. The microstructure of the hydroxy-functionalized aPS-b-random copolymer-b-PE was further confirmed by WAXD, C-13-NMR, and H-1-NMR analysis; and these results demonstrated that the obtained block copolymer consisted of aPS segment, S-E random copolymer segment, and crystalline PE segment. The connection polymerization of the hydroxy-functionalized aPS with random copolymer-b-PE was revealed by GPC results. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3171-3179, 2011

An effective workflow has been established that uses chiral as well as achiral stationary phases in combination with compound-specific gradient methods for fast mass-directed supercritical fluid chromatography (SFC) purification of complex mixtures. It has been used successfully to purify mixtures that show little or no separation in reversed-phase high performance liquid chromatography (HPLC).

A detailed experimental and theoretical study has been undertaken of the UV photofragmentation spectroscopy of the alkaline earth metal dications Mg(2+), Ca(2+), and Sr(2+) complexed with pyridine and 4-methyl pyridine (4-picoline). The ion complexes have been prepared using the pick-up technique and held in an ion trap where their internal temperature has been reduced to <150 K. Exposure of the trapped ions to tunable UV laser radiation leads to the appearance of photofragments with intensities that show significant variation as a function of wavelength. For all three metal dications, the resultant spectra show evidence of resolved features. Time-dependent density functional theory (TDDFT) has been used to identify possible electronic transitions that might be present in the [M(pyridine)(4)](2+) complexes (M = Mg, Ca, and Sr) within the wavelength range studied. These calculations show that the spectra are dominated by strong π* ← π and weaker π* ← n transitions localized on the pyridine ligands. The calculations correctly identify those regions of the experimental spectra where UV transitions begin to occur in the complexes and also the wavelengths at which absorption maxima are reached; however, more subtle features of the spectra are difficult to assign with confidence.

Star-shaped hydroxyl functionalized atacticpolymethylmethacrylate was synthesized via living/controlled radical polymerization promoted by titanocene complex in the presence of 4,4′-methylenebis(N,N-diglycidylaniline)(I4) as the initiator,and Zn as the reducing agent.The effect of polymerization conditions such as temperature,time,as well as the ratio of the initiator to monomer on the polymerization performance was investigated.The results indicate that the monomer conversion is up to 90% at 90 ℃ and / =200/1.The number average molecular weight of the polymer linearly depends on the monomer conversion,implying that the performance shows living manner.The structure and properties of the obtained polymer were characterized by gel permeation in chromatography(GPC),nuclear magnetic resonance spectrum(1H-NMR and 13C-NMR).The obtained polymer is atacticspecific and features narrow molecule weight distribution(1.41～1.65) under the typical condition.The number of arms and the functional hydroxyl groups of the polymer molecule are four,good corresponding with the number of the epoxy functional groups of the initiator(I4) used.

The star-shaped polymethylmethacrylate (PMMA) was synthesized via radical polymerization promoted by metallocene complexes in the presence of initiator of tetra(2,3-epoxy propoxy)silane (Is) and reducing agent Zn. The effect of temperature, time, molar ratio of monomer to initiator, and the structure of metallocene complexes on the polymerization performance was investigated. The structure and properties of the obtained polymer were characterized by gel permeation chromatography, multiangle laser light scattering, H-1 NMR, C-13 NMR, and WAXD. The results indicated that the obtained polymer was atacticspecific and featured narrow molecular weight distribution (1.30-1.57). Star-shaped organosiloxane-functionalized PMMA was produced. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1652-1658, 2011

Comb-like hydroxyl functionalized atactic polystyrene was synthesized using the catalytic system ( n-BuCp )2TiCl2/Sn/I8 via living radical polymerization with Sn as the reducing agent and poly- [ ( phenylglycidyl ether)-co-formaldehyde] (I8) as the initiator. The effect of polymerization conditions, such as temperature, time, as well as the ratio of initiator to monomer on the polymerization performance was investigated. The catalytic active center was stable at the temperature range of 65 ∼95°C ,and the propagation rate increased with temperature. The structure and the properties of the obtained polymer were characterized by GPC ,13 C-NMR, WAXD and1 H-NMR. The GPC result indicated that a linear dependence of Mn on the monomer conversion was observed in each case,and the resulting polymer exhibited a rather low polydispersity (Mw/Mn = 1.6∼1.9) even the polymerization time (6,8,12,16,18 h) or the ratio of initiator to monomer ([I8]/ [St] = 1/250, 1/500, 1/750) had been changed, which confirmed that living radical polymerization characters prevailed in the polymerization process. The results of 13 C-NMR and WAXD suggested that the polymer is featured by an atactic structure. The 1H-NMR results showed that the polymer molecules possessed hydroxyl groups,and the number of arms in each polymer molecule was in good agreement with the number of epoxy functional groups in the initiator (I8) ,which indicated the radicals derived from ring opening reaction of epoxide were the active species for living radical polymerization of styrene.

Well-defined comblike atactic polystyrene functionalized with hydroxyl groups was synthesized via living/controlling radical polymerization promoted by metallocene complexes in the presence of poly(phenyl glycidyl ether)-co-formaldehyde as the initiator and Sn as a reducing agent. The effect of the polymerization conditions, such as the ratio of initiator to monomer, temperature, and polymerization time, and the structure of the metallocene complex on the polymerization process were investigated. The resulting polymers were characterized by gel permeation chromatography, multiangle laser light scattering, H-1-NMR, and C-13-NMR. The results show that the polymer had a narrow molecular weight distribution in the range 1.1.-1.4 and the number-average molecular weight of the polymer linearly depended on the monomer conversion within the polymerization timescale, which confirmed that living radical polymerization characteristics prevailed in the polymerization process. Both the number of arms and the number of hydroxyl groups in each polymer molecule were about four, which suggested that they arose from the epoxy functional groups of the initiator. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1574-1580, 2010

A series of novel bridged multi-chelated non-metallocene catalysts is synthesized by the treatment of N,N-imidazole, N,N-dimethylimidazole, and N,N-benzimidazole with n-BuLi, 2,6-dimethylaniline, and MCl4 (M = Ti, Zr) in THF. These catalysts are used for copolymerization of ethylene with 1-hexene after activated by methylaluminoxane (MAO). The effects of polymerization temperature, Al/M molar ratio, and pressure of monomer on ethylene copolymerization behaviors are investigated in detail. These results reveal that these catalysts are favorable for copolymerization of ethylene with 1-hexene featured high catalytic activity and high comonomer incorporation. The copolymer is characterized by C-13 NMR, WAXD, GPC, and DSC. The results confirm that the obtained copolymer features broad molecular weight distribution (MWD) about 33-35 and high 1-hexene incorporation up to 9.2 mol %, melting temperature of the copolymer depends on the content of 1-hexene incorporation within the copolymer chain and 1-hexene unit in the copolymer chain isolates by ethylene units. The homopolymer of ethylene has broader MWD with 42-46. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 417-424, 2010

采用茂金属化合物(n-BuCp)2TiCl2, 还原剂 (Sn), 引发剂苯基缩水甘油基醚甲醛共聚物(Is) 组成的催化体系引发苯乙烯活性自由基聚合, 合成梳形羟基功能化无规聚苯乙烯. 考察了聚合温度、聚合时间及引发剂与单体的比例对苯乙烯聚合的影响. 当聚合温度在65～95℃范围内, 随着聚合温度的升高, 聚合物的分子量及单体转化率增加; 在一定温度下, 聚合物的分子量与单体转化率之间存在线性增长关系, 且聚合物的分子量分布较窄（Mw/Mn=1.6～1.9）. 采用GPC, WAXD,13C(1H)\|NMR对聚合物(沸丁酮可溶级分)的结构与性能进行了表征. GPC结果证明(n-BuCp)2TiCl2/Sn/Is引发苯乙烯聚合为活性聚合;13C-NMR和WAXD结果说明聚苯乙烯链段为无规结构;1H-NMR结果表明聚合物分子链中含有羟基, 并根据其结果计算出聚合物分子的臂数为4, 与引发剂Is的环氧基团数相等. 这些结果证明了其聚合机理是经环氧基团开环后形成的自由基引发苯乙烯自由基聚合.

Star-like hydroxyl functionalized atacticpolystyrene was synthesized via living radical polymerization promoted by the catalyst system (n-BuCp)2TiCl2/Sn/I4.Among the components of the catalyst system,Sn used as the reducing agent and 4,4’-methylenebis(N,N-diglycidylaniline)(I4) as the initiator.The effect of polymerization conditions,such as temperature,time,as well as the ratio of initiator to monomer on the polymerization performance was investigated.The obtained polymer was characterized by gel permeation in chromatography(GPC) and 13C nuclear magnetic resonance spectrum(13C-NMR).The GPC result indicates that a linear dependence of M-n on the monomer conversion is observed and a narrow polydispersity (M-w/M-n) of the resultant polymer is exhibited even the ratio of initiator to monomer ([I4]/[St] = 1/250,1/500,1/750) is changed,which confirmes that the polymerization behavior is of living radical polymerization.The 13C-NMR result indicates that the obtained polymer features atactic structure.

较全面地综述了配位聚合催化剂和聚合机理的研究进展:高效Ziegler-Natta催化剂催化丙烯、乙烯等烯烃高效聚合,可合成多种高性能聚烯烃,等规聚丙烯的等规度大于98.5%,不同结构和性能的聚乙烯包括线性低密度聚乙烯（LLDPE）、超低密度聚乙烯（VLDPE）、中密度聚乙烯（MDPE）、高密度聚乙烯（HDPE）、双/宽峰分布聚乙烯、超高分子量聚乙烯（UHMWPE）和超低密度双/宽峰分布聚乙烯等;茂金属催化剂催化苯乙烯、乙烯、丙烯、1-丁烯等烯烃的均聚合和共聚合,并概括了其聚合机理;非茂金属催化剂合成多组分、多立体结构嵌段的聚烯烃,极性聚烯烃及超支化聚烯烃等,介绍了链行走和链穿梭机理。展望了配位聚合的发展趋势,认为聚合过程的环境友好、产品使用过程的环境友好、聚烯烃的高性能化和功能化是从事配位聚合工作的全体人员努力的方向。

This paper reviews the preparation of biomedical polymer materials via living / controlled polymerization,including living free radical polymerization,living anionic polymerization,living cationic polymerization,and living coordination polymerization. They are used as non-viral gene delivery system,nanocarrier,medical carrier,artificial lung membrane,and so on. The trend of biomedical polymer materials in the future is also prospected.