Encrypting Chemical Reactivity in Protein Sequences toward Information‐Coded Reactions†

Controlling chemical reactivity has been the central theme in chemistry. Herein, we review the recent progress on the development of genetically encoded protein coupling reactions and their potential applications. The chemical reactivity is encoded in the protein sequences. The information is read out by folding and molecular recognition between two reactive components and subsequently translated into chemical bonding via autocatalysis. It has emerged as a unique way to tune the chemical reactivity and is regarded as one type of information‐coded reactions. Not only has it received many applications such as protein topology engineering, bioconjugation, biomaterials and synthetic biology, but also its principle may be extended beyond protein chemistry to enable new modes of supramolecular interactions that promote chemical bonding and that are simultaneously reinforced by covalent bonds.     

Sensitive Determination of DNA by Resonance Light Scattering with Pentamethoxyl Red

A novel sensitive method for the determination of nucleic acid (DNA) using the resonance light scattering (RLS) spectra of pentamethoxyl red has been developed. It is based on the effects on the resonance light scattering of Pentamethoxyl Red. The effective factors and the optimum conditions were studied, and the enhanced intensity of RLS is in proportion to the concentration of nucleic acids in the range of 0–2.54 µg mL⁻¹ for ct-DNA, 0–4.54 µg mL⁻¹ for hs-DNA. The limits of detection are 1.1 and 2.1 ng mL⁻¹, respectively. Most foreign substances do not interfere in the determination, and the method has good selectivity and high sensitivity. It has been applied to the determination of DNA in synthetic samples and in real samples with satisfactory results.     

Theoretical study on electronic structure and optical properties of phenothiazine-containing conjugated oligomers and polymers

The application of polyfluorenes in polymeric light-emitting diodes has been hampered because of the charge injection difficulties and the troublesome formation of a tailed emission band at long wavelengths (>500 nm) during device fabrication and operation, leading to both a color instability and reduced efficiency. The incorporation of the phenothiazine units has been proven to significantly enhance the hole injection and charge carrier balance and at the same time efficiently suppress the keto defect emission. In this contribution, we apply quantum-chemical techniques to investigate poly[10-(N-(2'-methyl)phenothiazine-3,7-diyl) and its fluorene copolymer poly[10-(N-(2'-methyl)phenothiazine-3,7-diyl)-co-alt-2,7-(9,9-dimethylfluorene)] (PFPTZ) and gain a detailed understanding the influence of phenothiazine units on the electronic and optical properties of fluorene derivatives. Density functional theory (DFT) and time-dependent DFT approaches are employed to study the neutral molecules, HOMO-LUMO gaps (Delta(H-L)), the lowest excitation energies (E(g)'s), positive and negative ions, as well as the IPs and EAs, focusing on the superiority of the electronic and optical properties attributed to the introduction of electron-donating moiety phenothiazine (PTZ) through comparing with pristine polyfluorene. The outcomes show that the highly nonplanar conformation of phenothiazine ring in the ground state preclude sufficiently close intermolecular interactions essential to forming aggregates or excimers. Furthermore, the HOMO energies lift about 0.4 eV, and thus, the IPs decrease about 0.3 eV in PFPTZ, suggesting the significant improved hole-accepting and transporting abilities, due to the electron-donating properties of phenothiazine ring by the presence of electron-rich sulfur and nitrogen heteroatoms and highly nonplanar characters, resulting in the enhanced performances in both efficiency and brightness compared with pristine polyfluorene. In addition, even though the introduction of electron-donating moiety PTZ onto fluorene leads to a slight bathochromic shift in absorption and emission spectra, the copolymer still exhibited strong blue emission.     

Amperometric monitoring of lactate accumulation in rabbit ischemic myocardium

Fabrication and characterization of miniature, flexible, planar biosensors for monitoring l-lactate accumulation in an ischemic myocardium are described. Three configurations of Au-based electrodes were fabricated by a photolithographic technique on flexible polyimide Kapton((R)) foil. All sensors are based on an immobilized lactate oxidase with amperometric detection of the enzymatically produced hydrogen peroxide at a platinum-electroplated-gold base electrode polarized at 0.5 V versus Ag/AgCl. An inner electropolymeric layer is used to prevent electrode fouling and to reject the interference effects of easily oxidizable molecules. In addition, a diffusion controlling outer layer that greatly enhances the linear dynamic range of the sensor, is obtained by casting a polyurethane external film. The developed sensor was evaluated in vitro and proved to have high selectivity, good operational stability, good accuracy and precision (average recovery = 102.3 +/- 0.4% for control sera), fast response time (t(95) = 20 s) and high upper limit of the linear dynamic range (25-80 mM, with sensitivity of 1.7-0.4 nA mM(-1) respectively at PO(2) = 15 mmHg). Subsequently, the sensor was brought into direct contact with the surface of the rabbit papillary muscle and used for continuous quantitative monitoring of extracellular lactate accumulation during no-flow ischemia.     

手性铜催化剂的制备及在环丙烷羧酯酯不对称合成中的应用

３类手性配体ｄ－１０－樟脑磺酸及其衍生物，α－（－）－羟蒎酮及其衍生物，又恶唑啉６衍生物分别与铜（Ⅱ）形成手性铜配合物，催化重氮乙酸酯与１，１－二苯乙烯或异丁烯的环丙烷化加成反应，得到光学活性环丙羧酸酯，不对称诱导最高可达９５％ｅ．ｅ．。     

铕(Ⅲ)-β-二酮-有机碱配合物的性质研究

希土－β－二酮－有机碱的配合物具有较强的发光性能，其性和作为高分子材料中的发光物质的应用研究发展－直较快。本文合成了九种铕（Ⅲ）－β－二酮－有机碱的配合物（ＥｕＬ３Ｂ），研究了配合物的ＩＲ，ＵＶ，荧光光谱和光电子能谱，并探讨了配体中Ｏ，Ｎ原子与Ｅｕ（Ⅲ）的配位性能。     

聚己内酯/硝基纤维素共混体系结晶行为的研究

通过对聚己内酯／硝基纤维素共混体系的热分析、傅立叶变换红外光谱的研究，证实了该共混体系在聚己内酯含量较高时，是一个热力学相容的体系，同时两组分之间存在强的氢键相互作用。在此体系中聚己内酯长成了清晰规整的环带球晶。聚己内酯结晶形态随结晶温度和共混物组成的变化表明，在共混体系中聚己内酯结晶速率与非晶第二组分的扩散速率存在一定的匹配关系，是影响环带球晶形成的重要因素。     

硝酸钐水合物热分解过程的研究

Sm(NO_3)_3·6H_2O热分解过程的研究工作虽有文献报道,但结果不尽相同。文献[2]不同于文献[1,3],认为分解过程中存在无水盐阶段;文献[3]不同于文献[1,2],认为分解过程中存在低水合物。而且文献尚缺低水合物热分解机理的报道。我们也曾做过一些工作,但脱水阶段也不详尽。为此,我们详细地研究了Sm(NO_3)_3·nH_2O(n=     

聚合条件对N-羧基-L-丙氨酸-环内酸酐开环聚合产物分子量的影响

用光气法制备了N-羧基-L-丙氨酸-环内酸酐(L-Alanine NCA).系统研究了L-Alanine NCA开环聚合反应过程中引发剂、溶剂、温度对聚合物分子量的影响.用硝基苯作溶剂,三乙胺作引发剂,所得聚合物特性粘度[η]=1.18.实验中发现,L-Alanine NCA可以顺利地进行热聚合反应。反应具有速率快,转化率高,分子量大的特点。甲苯溶剂中反应5小时所得聚合物[η]=2.35,高于采用引发剂的聚合体系产物的相应值。