Studies of a new series of ion-pair complexes [Mo(dtc)_4][Ln(dtc)_4] (Ln=La-Er,exp.Pm)

A new series of ion-pair complexes [Mo(dtc)4][Ln(dtc)4] (Ln=La-Er, exp. Pm) were synthesized from MoCl5, LnCl3 and Nadtc in anhydrous methanol. The crystal structures of the four complexes, [Mo(dtc)4][Ln(dtc)4] (Ln=Nd, Sm, Ho and Er) have been determined by X-ray diffraction. Spectroscopic properties of all these complexes are also discussed here.     

2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑的合成

通过对称双酰肼与P_2S_5的缩合反应合成2,5-二-羟苯基-1,3,4-噻二唑,并由此制备了2,5-二[2′-(4′-氯代苯氧乙酸)基]-1,3,4-噻二唑及其相关化合物,同时测定了它们的生物活性。     

"LIVING" FREE RADICAL SYNTHESIS OF NOVEL RODCOIL DIBLOCK COPOLYMERS WITH POLYSTYRENE AND MESOGEN-JACKETED LIQUID CRYSTAL POLYMER SEGMENTS*

The synthesis of rod-coil diblock copolymers was achieved for the firsttime by TEMPO-mediated "living" free radical polymerization of styrene and 2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene(MPCS). The block architecture of the two diblockcopolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was con-firmed by GPC, DSC studies and the formation of multimolecular micelles.     

甲醇在超临界环已烷中形成簇团的Monte Carlo初探

用Ｍｏｎｔｅ Ｃａｒｌｏ方法研究了甲醇－环己烷体系的微观结构随压力（密度）的变化情况，结果表明，在临界区域甲醇分子的聚集最为明显，形成的甲醇团簇尺寸最大，溶剂分子在甲醇周围的局部密度则在低于临界区或亚临界区较大。     

金属硫蛋白的聚合反应动力学

金属硫蛋白(Metallothionein,简称MT)是一类低分子量(哺乳动物MT的分子量为6500)、富含半胱氨酸(一般占氨基酸残量的30％)且具有高度可诱导性的金属结合蛋白。关于其结构与功能的研究是当今化学、生物学和临床医学等领域的重要课题之一。但是,有关各种生物MTs水溶液的热力学稳定性的研究尚未见报道。本文通过对在pH 7.40、4℃下放置不同时间的家兔肝脏(Cd,zn)_7MT水溶液进行HPLC分离,首次观察到MT在水溶液中的缓慢聚合现象,得到聚合反应的表观二级反应速率常数,发现MT-2比MT-1更易聚合。     

聚十二烷二元酸酯及其共聚酯的合成

通过直接熔融缩聚法合成了一系列聚十二烷二元酸酯，用GPC、^1H—NMR、FTIR对产物进行了表征，并讨论了预聚酯合成时催化剂浓度和种类、预聚反应温度、预聚初始醇酸摩尔比对聚合反应的影响。结果表明，在所选的三个催化剂体系中，氮化亚锡二水合物与对甲苯磺酸复合催化剂的催化效果最好；最佳反应条件：n对甲苯横酯／n二元酸=0．0021～0．0032，反应温度为160～180℃，醇酸摩尔比范围为1．05—1.10。     

Ab initio study of the complexes of halogen-containing molecules RX (X=Cl, Br, and I) and NH3: towards understanding the nature of halogen bonding and the electron-accepting propensities of covalently bonded halogen atoms

Ab initio calculations have been performed on a series of complexes formed between halogen-containing molecules and ammonia to gain a deeper insight into the nature of halogen bonding. It appears that the dihalogen molecules form the strongest halogen-bonded complexes with ammonia, followed by HOX; the charge-transfer-type contribution has been demonstrated to dominate the halogen bonding in these complexes. For the complexes involving carbon-bound halogen molecules, our calculations clearly indicate that electrostatic interactions are mainly responsible for their binding energies. Whereas the halogen-bond strength is significantly enhanced by progressive fluorine substitution, the substitution of a hydrogen atom by a methyl group in the CH(3)X...NH(3) complex weakened the halogen bonding. Moreover, remote substituent effects have also been noted in the complexes of halobenzenes with different para substituents. The influence of the hybridization state of the carbon atom bonded to the halogen atom has also been examined and the results reveal that halogen-bond strengths decrease in the order HC triple bond CX > H(2)C=CHX approximately O=CHX approximately C(6)H(5)X > CH(3)X. In addition, several excellent linear correlations have been established between the interaction energies and both the amount of charge transfer and the electrostatic potentials corresponding to an electron density of 0.002 au along the R-X axis; these correlations provide good models with which to evaluate the electron-accepting abilities of the covalently bonded halogen atoms. Finally, some positively charged halogen-bonded systems have been investigated and the effect of the charge has been discussed.     

Oxidative coupling of methane over Na-Mn-W/SiO2 catalyst at higher pressure

Na-Mn-W/SiO₂ catalysts were prepared and their catalytic performance for oxidative coupling of methane (OCM) was evaluated in a stainless-steel microreactor at elevated pressure. The results show that a CH₄ conversion of 15.1% with a C₂₊ selectivity of 71.8% was obtained under 750^oC, 1.0×10⁵h^-1 GHSV, CH₄/O₂ ratio of 8 and 1.0 MPa. Moreover, 17.3% CH₄ conversion with 51.6% C₂ selectivity and 23.6% C₃-C₄ selectivity was obtained under 750^oC, 2.0×10⁵h^-1 GHSV, CH₄/O₂ ratio of 8 and 1.0 MPa.     

Accelerated Hydrolysis of p-Nitrophenyl Picolinate Catalyzed by Metallomicelle Made from a Novel Macrocyclic Polyamine Copper（Ⅱ） Complex

A copper（Ⅱ） complex 1 of a novel macrocyclic polyamine ligand with hydroxylethyl pendant groups, 4,11-bis（hydroxylethyl）-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane （L） has been synthesized and characterized. Rate enhancement for hydrolysis of p-nitrophenyl picolinate （PNPP） catalyzed by 1 was studied kinetically under Brij35 micellar condition. For comparision, the catalytic activity of corresponding copper（Ⅱ） complex 2 of non-substituted macrocyclic polyamine ligand, 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraaza-cyclotetradecane （L＇） toward the hydrolysis of PNPP was also investigated. The results indicate that the macrocyclic polyamine copper（Ⅱ） complex 1 effectively catalyzed the hydrolysis of PNPP, and the pendant ligand hydroxyl group or deprotonated pendant ligand hydroxyl group can act as catalytically active species in the reaction. A ternary Complex kinetic model involving metal ion, ligand and substrate has been proposed, and the results confirmed the reasonability of such kinetic model.