Synthesis and reactivity of rare earth metal alkyl complexes stabilized by anilido phosphinimine and amino phosphine ligands

Anilido phosphinimino ancillary ligand H2L1 reacted with one equivalent of rare earth metal trialkyl [Ln{CH2Si(CH3)(3)}(3)(thf)(2)] (Ln = Y, Lu) to afford rare earth metal monoalkyl complexes [L(1)LnCH(2)Si(CH3)(3)(THF)] (1a: Ln = Y; 1b: Ln = Lu). In this process, deprotonation of H2L1 by one metal alkyl species was followed by intramolecular C-H activation of the phenyl group of the phosphine moiety to generate dianionic species L-1 with release of two equivalnts of tetramethylsilane. Ligand L-1 coordinates to Ln(3+) ions in a rare C,N,N tridentate mode. Complex 1a reacted readily with two equivalents of 2,6-diisopropylaniline to give the corresponding bis-amido complex [(HL1)LnY(NHC(6)H(3)iPr(2)-2,6)(2)] (2) selectively, that is, the C-H activation of the phenyl group is reversible. When 1a was exposed to moisture, the hydrolyzed dimeric complex [{(HL1)Y(OH)}(2)](OH)(2) (3) was isolated. Treatment of [Ln{CH2Si(CH3)(3)}(3)-(thf)(2)] with amino phosphine ligands HL2-R gave stable rare earth metal bisalkyl complexes [(L2-R)Ln{CH2Si(CH3)(3)}(2)(thf)] (4a: Ln=Y, R=Me; 4b: Ln=Lu, R=Me; 4c: Ln=Y, R=iPr; 4d: Ln=Y, R=iPr) in high yields. No proton abstraction from the ligand was observed. Amination of 4a and 4c with 2,6-diisopropylaniline afforded the bis-amido counterparts [(L2-R)Y(NHC(6)H(3)iPr(2)-2,6)(2)(thf)] (5a: R=Me; 5b: R=iPr).

Influence of the degree of grafting on the morphology and mechanical properties of blends of poly(butylene terephthalate) and glycidyl methacrylate grafted poly(ethylene-co-propylene) (EPR)

Poly(ethylene-co-propylene) (EPR) was functionalized to varying degrees with glycidyl methacrylate (GMA) by melt grafting processes. The EPR-graft-GMA elastomers were used to toughen poly(butylene terephthalate) (PBT). Results showed that the grafting degree strongly influenced the morphology and mechanical properties of PBT/EPR-graft-GMA blends. Compatibilization reactions between the carboxyl and/or hydroxyl of PBT and epoxy groups of EPR-graft-GMA induced smaller dispersed phase sizes and uniform dispersed phase distributions. However, higher degrees of grafting (>1.3) and dispersed phase contents (>10 wt%) led to higher viscosities and severe crosslinking reactions in PBT/EPR-graft-GMA blends, resulting in larger dispersed domains of PBT blends. Consistent with the change in morphology, the impact strength of the PBT blends increased with the increase in EPR-graft-GMA degrees of grafting for the same dispersion phase content when the degree of grafting was below 1.8. However, PBT/EPR-graft-GMA1.8 displayed much lower impact strength in the ductile region than a comparable PBT/EPR-graft-GMA1.3 blend (1.3 indicates degree of grafting).

20世纪稀土科技发展的回顾与前瞻

本文对20世纪各个时期稀土科技的重大发展作了回顾,并对21世纪初期稀土可能取得的重大应用作了展望。

Fragmentation reactions of adduct ions [M+CH3CO](+) of isomeric phenylenediamines

The dissociation routes of the adduct ions [M+CH3CO](+) formed by ion-molecule reaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionization condition were investigated by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.

Synthesis and characterization of novel crosslinkable side-chain liquid crystalline polyesters

Crosslinkable side-chain liquid crystalline polyesters PCn from N-[n-(4-(4-nitrophenylazo)phenyloxy)alkyl]diethanolamine (Cn, n = 3, 5, 6, 10) as mesogenic monomers and maleic anhydride were synthesized and characterized. The thermal properties of PCn's were studied by means of DSC, polarized optical microscopy (POM) and wide angle X-ray diffraction (WAXD), and the results showed that all the polymers studied exhibit enantiotropic liquid crystallinity. In the molar mass independent region, the relatively high content of cis -CH=CH- groups in the polymer backbone of PC3 causes an increase of the melting temperature (T-m) and a decrease of T-g and isotropisation temperature (T-i). The crosslinking of PCn in the radical polymerization with styrene was confirmed by FTIR spectroscopy. The absorption band at 1300 cm(-1) attributed to the in-plane C-H-bending vibration of trans -CH=CH- in the polymer backbone disappeared after crosslinking, indicating that the trans -CH=CH- functions are consumed in the crosslinking polymerization of styrene.

Electrochemical study of interactions between DNA and viologen-thiol self-assembled monolayers

We investigated the binding characteristics of double-stranded DNA to self-assembled monolayers (SAMs) containing viologen groups formed on the surface of gold electrodes via Au-S bonds. The positive charged and hydrophobic surfaces of the viologen SAMs modified gold electrodes are suitable to bind strongly dth DNA, whose interactions to solution DNA and adsorbed DNA both lead to positive shifts (22.5 mV and 65 mV, respectively) in the first redox potential ci viologen centers, indicating that the main interaction is from a hydrophobic interaction. Meanwhile, the binding of DNA strongly affects the kinetics of electron transfer of the viologen group so that the separation of anodic and cathodic peak potentials becomes larger and the heterogeneous electron transfer constant becomes smaller.

1,5,9-环十二碳三烯的阳离子型跨环齐聚合反应

本文研究1,5,9-环十二碳三烯在阳离子型引发剂AlCl_3和BF_3·OEt_2催化下进行的跨环聚合反应,考察各种反应条件对跨环聚合反应的影响。产物为白色粉末,分子量均在1096—1431之间。对其溶解性、核磁共振和红外光谱的分析,确认了它的结构。

Molecular cloning, characterization and expression of a novel serine proteinase inhibitor gene in bay scallops (Argopecten irradians, Lamarck 1819)

Serine protease inhibitors, critical regulators of endogenous proteases, are found in all multicellular organisms and play crucial roles in host physiological and immunological effector mechanisms. The first mollusk serine proteinase inhibitor (designated AISPI) cDNA was obtained from the bay scallop Argopecten irradians by randomly sequencing a whole tissue cDNA library and rapid amplification of cDNA ends (RACE). The full-length cDNA of the scallop serine protease inhibitor was 1020 bp, consisting of a 5'-terminal untranslated region (UTR) of 39 bp, a 3'-terminal UTR of 147 bp with a canonical polyadenylation signal sequence AATAAA and a poly(A) tail, and an open reading frame of 834 bp. The AISPI cDNA encoded a polypeptide of 278 amino acids with a putative signal peptide of 22 amino acids and a mature protein of 256 amino acids. The deduced amino-acid sequence of AISPI contained six tandem and homologous domains similar to that of Kazal-type serine protease inhibitors, including the conserved sequence C-X(7)-C-X(6)-Y-X(3)-C-X(2,3)-C and six cysteine residues responsible for the formation of disulfide bridges, indicating that the AISPI protein from bay scallop should be a member of the Kazal-type serine protease inhibitor family. The temporal expression of AISPI was measured by semi-quantitative RT-PCR after injury or bacterial challenge. After the adductor muscle was wounded or injected with Vibrio anguillarum, the expression of AISPI mRNA in hemolymph was up-regulated and reached the maximum level at 8 and 16 h, respectively, and then progressively dropped back to the original level. The results indicated that AISPI could play an important role in injury healing and immune response in mollusks as it could be induced by injury and bacterial challenge. (c) 2005 Elsevier Ltd. All rights reserved.

Discovery of Late Cretaceous garnet two-pyroxene granulite in the southern Lhasa terrane, Tibet and its tectonic significances

The Lhasa terrane, located between the Bangonghu-Nujiang suture zone and the Indus-Yalung Tsangpo suture zone in the southern Tibetan Plateau, was considered previously as a Precambrian continental block. Mesozoic and Cenozoic tectonic evolution of the Lhasa terrane is closely related to the subduction of the Tethys ocean and the collision between the Indian and European continents; so it is one of the keys to reveal the formation and evolution of the Tibetan plateau. The garnet two-pyroxene granulite which was found at the Nyingtri rock group of the southeastern Lhasa terrene consists of garnet, clinopyroxene, orthopyroxene, labradorite, Ti-rich amphibolite and biotite, with a chemical composition of mafic rock. The metamorphic conditions were estimated to be at T = 747 similar to 834 degrees C and P = 0.90 similar to 1.35GPa, suggesting a formation depth of 45km. The zircon U-Pb dating for the garnet amphibolite and marble associated with the granulite give a metamorphic age of 85 similar to 90Ma. This granulite-facies metamorphic event together with a contemporaneous magmatism demonstrated that the southern Lhasa terrane has undergone an Andean-type orogeny at Late Mesozoic time.

冲绳海槽黑潮流域近4万年以来的古海洋环境演化

本文采用取自冲绳海槽的91个站位的表层样品和2个柱状岩芯，通过微体古生物有孔虫分析、氧碳同位素测试、AMS~(14)C测年、沉积物粒度和地球化学分析，探讨了现代生物群落、表层沉积物氧同位素与现代海洋环境之间的关系，进而对冲绳海槽区域近4万年来的古海洋环境和古黑潮演化进行了详细的研究。表层沉积物中的浮游有孔虫氧同位素与现代海洋环境之间的关系密切，浮游有孔虫从G.ruber到G.sacculifer到N.dutertrei其δ~(18)O值由轻变重，表明三种有孔虫其生活水层依次由浅到深。在横穿海槽的剖面上浮游有孔虫δ~(18)O在近陆端因受冲淡小影响较强而变轻，而在东侧站位，受黑潮暖流或其支流的影响氧同位素同样有变轻的趋势。N. dutertrei和G.ruber的氧同位素差值表明了冲绳海槽北部区域黑潮支流对表层水体的影响要大于次表层水体，而在冲绳海槽南部区域，黑潮暖流对次表层水体有相对较强的影响。冲绳海槽南部表层沉积物中的浮游有孔虫整体上属于赤道区组合，溶解作用对该区的浮游有孔虫群落有显的影响，冲绳海槽北部区浮游有孔虫组合对具有温带群落的特征。浮游有孔虫分布与海洋环境密切相关，南北区的浮游有孔虫分布都明显受暖流的影响，在暖流的主流轴处浮游有孔虫丰度通常较高。冲绳海槽具有相对较浅的碳酸盐溶跃面，浮游有孔虫丰度和底栖有孔虫深水胶结壳的含量都进一步表明了该区碳酸钙溶跃面大约在1700 m水深左右，比开放大洋明显要浅得多。表层沉积物中的底栖有孔虫主要受水深和水团等因素的制约。水深制约着有孔虫属种的分带，也影响底栖有孔虫的组合。根据Q型因子分析，冲绳海槽南部表层沉积物中的底栖有孔虫从陆架连缘到海槽底部可以划分为5个特定的组合，分别对应黑潮表层水和次层水影响环境、黑潮中层水影响环境、溶跃面以上的黑潮深层水影响环境、黑潮底层水团影响环境和溶解作用较强的槽底环境；北部区的底栖有孔虫群落反映了四个组合，分别代表了陆架混合水团影响环境、黑潮暖流中层水影响环境、冷涡沉积和上升流区影响环境以及对马暖流水团影响下的环境。以氧同位素曲线为基础，结合AMS~(14)C测年和生物地层学对柱状岩芯进行了地层划分和对比，E107孔记录了冰消期以来大约15,000 a来的古环境演化记录，具有较高的沉积速率，DOC－42孔保存在主要是末冰期中40－10ka BP期间的古环境沉积记录，沉积物记录的分辨率相对较低。浮游有孔虫有碎壳比和底栖有孔虫深海胶结壳含量表明了现代冲绳海槽的浅溶跃面是大约最近2000 a BP才开始突然变浅形成的，碳酸盐的溶解作用从冰消期到现在逐增强。冲绳海槽南部E107孔的底栖有孔虫组合把映了15,000 a来的底层水团具有两种完全不同的营养状况，约6500 a BP以前有机质通量较高，6500 a BP以后有机质通量则明显降低。DOC－42孔的底栖有孔虫组合反映该区约4万年以来的底部水团演化主要受有机质通量和氧含量的共同制约，氧同位素3期主要为高有机质通量的沉积环境，伴随有氧含量水平的较大波动；氧同位素2期有机质通量有所降低，氧含量整体为中等水平；氧同位素1期早期义部水体则较高氧含量为主。浮游有孔虫温跃层转换函数反映了冲绳海槽中部的温跃层在约13100 a BP有一个明显的变化，在这之前产温跃层深度较浅，平均89 m，而在该时间以后，温跃层平均深度变为166 m。此外在160 cm处和100 cm的温跃层深度的两次明显的降低，分别对应于新仙女木事件和黑潮暖流的重新入侵，表明这两个事件导致了海洋上层水体结构的突然变化。冲绳海槽北部浮游有孔虫转换函数古温度和浮游有孔虫的低温、低盐特征种反映了在氧同位素3期早期约40000a BP和氧同位素2期间存在两个明显的低温、低盐阶段，可能与沿岸水在该期间加强有关。其中氧同位素3期早期的表层海水古水温比末次冰期还要低，反映了区域海洋环境的重大变化。冲绳海槽南部E107孔的沉积物粒度、地球化学特征、黑潮特征指示种、表层古水温以及底层水团的性质在6500 a BP左右发生了重大的改变，与冲绳海槽南部的其他岩芯反映的古环境化基本一致，表明了南部海槽在6500 a BP前后古黑潮流径发生了重大变化。而冲绳海槽北部区域2万年以来的古环境则与南部有明显差异，总结前人对冲绳海槽古黑潮流径的研究，笔者对未次冰盛期古黑潮流径提出了新的推测。

First record of marine crab, Eucrate alcocki SerSne, in SerSne and Lohavanijaya, 1973 (Crustacea, Decapoda, Brachyura, Euryplacidae) from India

This paper reports the occurrence of a marine brachyuran crab species Eucrate alcocki SerSne, in SerSne et al., 1973, of the family Euryplacidae Stimpson, 1871, for first time from India, based on a male specimen from Parangipettai fish landing centre in Bay of Bengal, Southeast Coast of India. Although morphologically corresponding with what is currently defined as E. alcocki, the color pattern of the carapace of the present specimen is rather different from that of the Chinese material-only the anterior fifth of the carapace is marked with scattered red spots, the rest of the surface is yellowish, with four unusually shaped red blotches which almost look like Sanskrit characters.

藏成药安神丸脂溶性提取物对大鼠脂质代谢及抗氧化功能的影响

目的 观察藏成药安神丸饱和脂及不饱和脂提取物对大鼠脂质代谢及抗氧化功能的影响。方法 测定连续ig给药4周、8周及给药8周又停药4周后大鼠血清中丙二醛（MDA）、还原型谷胱甘肽（GSH）及高密谋脂蛋白（HDL）的含量。结果 安神丸的脂溶性提取物可明显增加较大龄鼠血清中的GSH和HDL含量。结论 安神丸脂溶性提取物可改善较大龄鼠脂质代谢功能，提高其抗氧化能力。

祁连山海北高寒草甸地区植物生长期的光合有效辐射特征

分析了祁连山海北高寒草甸地区1998年植物生长期内光合有效辐射（PAR）的日、季节变化特征。结果表明：PAR日变化与太阳总辐射（E_g）日变化趋势一致，表现为单峰型变化过程，日总量最大可达11.7MJ·m~(-2)左右。植物生长期内的4月下旬～9月中旬季节变化较为复杂，雨季来临之前的4～6月较高，其它时间较低，旬平均最高在5月达85.23MJ·cm~(-2)。PAR在E_g中所占的比例（η）晴天状况下日平均在0.36～0.41之间，阴天稍高，植物生长期内η的旬平均在0.32～0.43之间。分析还表明，PAR与E_g日总量具有很好的正相关关系，从而可依E_g的变化量来估算PAR。同时计算表明，海北高寒草甸地区植物群落对PAR的光能利用率为0.58%左右。

Phylogeography of the Qinghai-Tibetan Plateau endemic Juniperus przewalskii (Cupressaceae) inferred from chloroplast DNA sequence variation

The vegetation of the northeast Qinghai-Tibetan Plateau is dominated by alpine meadow and desert-steppe with sparse forests scattered within it. To obtain a better understanding of the phylogeography of one constituent species of the forests in this region, we examined chloroplast trnT-trnF and trnS-trnG sequence variation within Juniperus przewalskii, a key endemic tree species. Sequence data were obtained from 392 trees in 20 populations covering the entire distribution range of the species. Six cpDNA haplotypes were identified. Significant population subdivision was detected (G(ST) = 0.772, N-ST = 0.834), suggesting low levels of recurrent gene flow among populations and significant phylogeographic structure (N-ST > G(ST), P < 0.05). Eight of the nine disjunct populations surveyed on the high-elevation northeast plateau were fixed for a single haplotype (A), while the remaining, more westerly population, contained the same haplotype at high frequency together with two low frequency haplotypes (C and F). In contrast, most populations that occurred at lower altitudes at the plateau edge were fixed or nearly fixed for one of two haplotypes, A or E. However, two plateau edge populations had haplotype compositions different from the rest. In one, four haplotypes (A, B, D and E) were present at approximately equivalent frequencies, which might reflect a larger refugium in the area of this population during the last glacial period. Phylogenetic analysis indicated that the most widely distributed haplotype A is not ancestral to other haplotypes. The contrasting phylogeographic structures of the haplotype-rich plateau edge area and the almost haplotype-uniform plateau platform region indicate that the plateau platform was recolonized by J. przewalskii during the most recent postglacial period. This is supported by the findings of a nested clade analysis, which inferred that postglacial range expansion from the plateau edge followed by recent fragmentation is largely responsible for the present-day spatial distribution of cpDNA haplotypes within the species.