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).

Synthesis, structure and norbornene polymerization behavior of neutral palladium complexes

A series of neutral palladium(II) complexes bearing non-symmetric bidentate pyrrole-iminato or salicylaldiminato chelate ligands have been synthesized, and the structure of representative complexes (3a, 4a, and 5a) have been confirmed by X-ray crystallographic analysis. These palladium complexes have been investigated as catalysts for the polymerization of norbornene. Using modified methylaluminoxane (MMAO) as a cocatalyst, these complexes display high activities and produce vinyl-addition polynorborenes. Catalytic activity of up to 8.52 x 10(3) kg/mol(Pd) h has been observed. Wide-angle X-ray diffraction (WAXD) has been used to investigate the polymer microstructure and it has been found that they are non-crystalline.

Preparation of linear alpha-olefins to high-molecular weight polyethylenes using cationic alpha-diimine nickel(II) complexes containing chloro-substituted ligands

A series of alpha-diimine nickel(II) complexes containing chloro-substituted ligands, [(Ar)N=C(C10H6)C=N(Ar)]NiBr2 (4a, Ar = 2,3-C6H3Cl2; 4b, Ar = 2,4-C6H3Cl2; 4c, Ar = 2,5-C6H3Cl2; 4d, Ar = 2,6-C6H3Cl2; 4e, Ar = 2,4,6-C6H2Cl3) and [(Ar)N=C(C10H6)C=N(Ar)](2)NiBr2 (5a, Ar = 2,3-C6H3Cl2; 5b, Ar = 2,4-C6H3Cl2; 5c, Ar = 2,5-C6H3Cl2), have been synthesized and investigated as precatalysts for ethylene polymerization. In the presence of modified methylaluminoxane (MMAO) as a cocatalyst, these complexes are highly effective catalysts for the oligomerization or polymerization of ethylene under mild conditions. The catalyst activity and the properties of the products were strongly affected by the aryl-substituents of the ligands used. Depending on the catalyst structure, it is possible to obtain the products ranging from linear alpha-olefins to high-molecular weight polyethylenes.

Synthesis and characterization of novel lanthanocene complexes with dichalcogenolate o-carboranyl ligands

Reactions of [ Cp(2)Ln(mu-Cl)](2) (Cp = eta(5)-C5H5, Ln = Nd, Yb, Dy, Gd, Er) with an equivalent of [ (THF)(3)LiE2C2B10H10Li. (TT-IF) (THF)](2) (E = S, Se) in THF afforded the dinuclear sandwich complexes of formula[Cp(2)LnE(2)C(2)B(10)H(10)](2)[Li(THF)(4)](2) [E = S, Ln = Nd (1a), Yb (2a), Dy (3a), Gd (4a), Er (5a); E = Se, Ln = Nd (1b), Yb (2b), Dy (3b), Gd (4b), Er (5b)]. The molecular structures of complexes la, 2a and 2b were determined by the single crystal X-ray structure analyses. Two lanthanide atoms are connected by a pair chalcogen (eta(1), eta(2)-E2C2B10H10) bridging ligands and the central Ln(2)E(2) four membered ring is not planar.

利用~1H-核磁共振谱计算环化丁苯橡胶的环化度和溶剂参与量

对环化丁苯橡胶的1 H 核磁共振谱进行了归属分析 ,并推导出计算环化度和溶剂参与量的公式。设环化丁苯橡胶的1 H 核磁共振谱图中化学位移为 7 0 ,5 4,4 9和 3 0～ 0处的峰强度分别为A ,B ,C和D ,则环化丁苯橡胶中丁二烯总物质的量 (X) =(B +C +D - 2A) /7 1 ,未环化的丁二烯物质的量 (Y) =B/2 +C/4,参与反应的二甲苯物质的量 (Z) =( 1 7 5A -B -C -D) /46 5,环化度 (P) =1 -Y/X ,溶剂参与量 (W ) =91 6Z/X。

The photo-induced decarbonylation of Cp ' M(NO)(CO)(2) (M = Cr, Mo, W) with diorgano dichalcogenides (R2E2; E = S, Se; R = Me, Ph)

The photo-induced decarbonylation of Cp'Cr(NO)(CO)(2) (1a) in MeCN solution in the presence of R2E2 (E = S, Se; R = Me, Ph) leads to the formation of chalcogenolato-bridged binuclear complexes Cp-2'Cr-2(NO)(2)(mu -ER)(2) [E = S; R = Me (2a), Ph (3a); E = Se, R = Me (4a), Ph (5a)] while reactions between Cp'M(NO)(CO)(2) [M = Mo (1b), W (1c)] and Ph2E2 (E = S, Se) result in mononuclear complexes Cp'M(NO)(EPh)(2) [M = Mo; E = S (9b), Se (10b); M = W, E = S (11c), Se (12c)]. The corresponding reactions of (1b) with Me2E2 (E = S, Se) yielded both mono and binuclear complexes: Cp'Mo(NO)(SeMe)(2) (8b), Cp-2'Mo-2(NO)(2)(mu -EMe)(2) [E = S (6b), Se (7b)]. The new complexes have been characterized by i.r., H-1-, C-13-n.m.r. spectra and by electron-impact mass spectrometry.

Half-sandwich cyclopentandienyl molybdenum and tungsten nitrosyl complexes containing bidentate sulfur ligands

Half-sandwich nitrosyl complexes Cp*M(NO)I-2 (M = Mo, or W) react with dithiocarbamates (NaS2CNMe2 and NaS2CNEt2) in THF to form of complexes: Cp*Mo(NO)I (S2CNMe2) (1), Cp*Mo(NO)I(S2CNEt2) (2), Cp*W(NO)I(S2CNMe2) (3) and Cp*W(NO)I(S2CNEt2) (4) in high yields. Treatments of Cp*M(NO)I-2 (M = Mo, W) or [CpMo(NO)I-2](2) with phosphinodithioate (NaS2PMe2) and phosphorodithioate [(NH4)S2P(OMe)(2)] result in complexes: Cp*Mo(NO)I(S2PMe2) (5a), CpMo(NO)I (S2PMe2) (5b), Cp*Mo(NO)(S2PMe2)(2) (6a), CpMo (NO) (S2PMe2)(2) (6b) and Cp*Mo(NO)I[S2P(OMe)(2)] (7), Cp*W(NO)I(S2PMe2) (8), Cp*W(NO) I[S2P(OMe)](2) (9). Treatment of (5a) and (5b) with an excess of NaS2PMe2 gives (6a) and (6b). The complexes have been characterized by their elemental analyses, i.r., H-1, C-13-n.m.r. and by EI-MS spectrometry.

THE STUDY OF MOSSBAUER-EFFECT IN EUBA2CU3O7-Y

EuBa2(Cu1-xFex)3O7-y has been investigated by the Fe-57 and Eu-151 Mossbauer effect. The Fe-57 Mossbauer spectra of the EuBa2(Cu1xFex)3O7-y without or with DC electric current (the current strength I = 0.5A) around the superconducting transition temperature have been measured. The results indicate that the isomer shift (IS) and the quadrupole splitting (QS) of the Fe replacing the Cu(2) vary neither with increasing the Fe content nor with the small DC eletric current passing the superconductor and that the IS and the QS of the Fe replacing the Cu(1) vary with the Fe content. Especially, the IS and the QS of the Fe (D3) replacing the Cu(1) are changed when the small electric current passes the superconductor at 80K.

镁钕合金中铁镍钼铜和硅的光谱测定

镁钕合金是航空、宇航等工业所需要的一种合金,它具有比重轻、强度大等优点,所以引起人们的注意。根据冶炼的要求,建立了镁钕合金中Fe、Ni、Mo、Cu和Si的光谱分析方法。本方法具有较好的再现性,回收率较高、简单、方便等优点,易于推广。 一、实验条件 仪器:ИСП-28中型光谱仪,三透镜照明系统,中间光栏5mm,狭缝宽12μm。直流电孤,粉末法,5A,阳极激发,曝光41S。 试样:镁钕合金先用稀硝酸洗去外部的污物,然后用蒸馏水、去离子水、二次蒸馏

双烯烃聚合催化剂——n-C_4H_9NdH_2·3LiOCH_3

近年来,文献上相继报道了稀土有机化合物对双烯烃聚合的研究结果。我们亦曾报道当Nd(OCH_3)_3和n-C_4H_9Li以摩尔比1:3反应时,可以分离到一类新的有机钕氢化物n-C_4H_9NdH_2·3LiOCH_3,并发现它可以在较低温度下和苯乙烯反应生成乙基苯。本文研究了它和丁二烯的反应,结果表明,n-C_4H_9NdH_2·3LiOCH_3可以单独用于催化丁二烯聚合。 丁二烯为聚合级。庚烷(分析纯)用5A分子筛干燥。n-C_4H_9NdH_2·3LiOCH_3的合成见文献。聚合在容积为30ml的聚合瓶中进行,在氮气下依次加入丁二烯庚烷溶液

The variability of eddy kinetic energy in the South China Sea deduced from satellite altimeter data

We used fifteen years (1993-2007) of altimetric data, combined from different missions (ERS-1/2, TOPEX/Poseidon, Jason-1, and Envisat), to analyze the variability of the eddy kinetic energy (EKE) in the South China Sea (SCS). We found that the EKE ranged from 64 cm(2)/s(2) to 1 390 cm(2)/s(2) with a mean value of 314 cm(2)/s(2). The highest EKE center was observed to the east of Vietnam (with a mean value of 509 cm(2)/s(2)) and the second highest EKE region was located to the southwest of Taiwan Island (with a mean value of 319 cm(2)/s(2)). We also found that the EKE structure is the consequence of the superposition of different variability components. First, interannual variability is important in the SCS. Spectral analysis of the EKE interannual signal (IA-EKE) shows that the main periodicities of the IA-EKE to the east of Vietnam, to the southwest of Taiwan Island, and in the SCS are 3.75, 1.87, and 3.75 years, respectively. It is to the south of Taiwan Island that the IA-EKE signal has the most obvious impact on EKE variability. In addition, the IA-EKE exhibit different trends in different regions. An obvious positive trend is observed along the east coast of Vietnam, while a negative trend is found to the southwest of Taiwan Island and in the east basin of Vietnam. Correlation analysis shows that the IA-EKE has an obvious negative correlation with the SSTA in Nio3 (5A degrees S-5A degrees N, 90A degrees W-150A degrees W). El Nio-Southern Oscillation (ENSO) affects the IA-EKE variability in the SCS through an atmospheric bridge-wind stress curl over the SCS. Second, the seasonal cycle is the most obvious timescale affecting EKE variability. The locations of the most remarkable EKE seasonal variabilities in the SCS are to the east of Vietnam, to the southwest of Taiwan, and to the west of Philippines. To the east of Vietnam, the seasonal cycle is the dominant mechanism controlling EKE variability, which is attributed primarily to the annual cycle there of wind stress curl. In this area, the maximum EKE is observed in autumn. To the southwest of Taiwan Island, the EKE is enlarged by the stronger SCS circulation, which is caused by the intrusion branch from the Kuroshio in winter. Finally, intra-annual and mesoscale variability, although less important than the former, cannot be neglected. The most obvious intra-annual and mesoscale variability, which may be the result of baroclinic instability of the background flow, are observed to the southwest of Taiwan Island. Sporadic events can have an important effect on EKE variability.

Bifurcation of Pacific North Equatorial Current at the surface

The grid altimetry data between 1993 and 2006 near the Philippines were analyzed by the method of Empirical Orthogonal Function (EOF) to study the variation of bifurcation of the North Equatorial Current at the surface of the Pacific. The relatively short-term signals with periods of about 6 months, 4 months, 3 months and 2 months are found besides seasonal and interannual variations mentioned in previous studies. Local wind stress curl plays an important role in controlling variation of bifurcation latitude except in the interannual timescale. The bifurcation latitude is about 13.3A degrees N in annual mean state and it lies at the northernmost position (14.0A degrees N) in January, at the southernmost position (12.5A degrees N) in July. The amplitude of variation of bifurcation latitude in a year is 1.5A degrees, which can mainly be explained as the contributions of the signals with periods of about 1 year (1.2A degrees) and 0.5 year (0.3A degrees).

A quasi-synoptic interpretation of water mass distribution and circulation in the western North Pacific II: Circulation

Using the data of conductivity-temperature-depth (CTD) intensive observations conducted during Oct.-Nov. 2005, this study provides the first three-dimension quasi-synoptic description of the circulation in the western North Pacific. Several novel phenomena are revealed, especially in the deep ocean where earlier observations were very sparse. During the observations, the North Equatorial Current (NEC) splits at about 12A degrees N near the sea surface. This bifurcation shifts northward with depth, reaching about 20A degrees N at 1 000 m, and then remains nearly unchanged to as deep as 2 000 m. The Luzon Undercurrent (LUC), emerging below the Kuroshio from about 21A degrees N, intensifies southward, with its upper boundary surfacing around 12A degrees N. From there, part of the LUC separates from the coast, while the rest continues southward to join the Mindanao Current (MC). The MC extends to 2 000 m near the coast, and appears to be closely related to the subsurface cyclonic eddies which overlap low-salinity water from the North Pacific. The Mindanao Undercurrent (MUC), carrying waters from the South Pacific, shifts eastward upon approaching the Mindanao coast and eventually becomes part of the eastward undercurrent between 10A degrees N and 12A degrees N at 130A degrees E. In the upper 2 000 dbar, the total westward transport across 130A degrees E between 7.5A degrees N and 18A degrees N reaches 65.4 Sv (1 Sv = 10(-6) m(3)s(-1)), the northward transport across 18A degrees N from Luzon coast to 130A degrees E is up to 35.0 Sv, and the southward transport across 7.5A degrees N from Mindanao coast to 130A degrees E is 27.9 Sv.

Characteristics of nonlinear internal waves observed in the northern South China Sea

The South China Sea (SCS) is one of the most active areas of internal waves. We undertook a program of physical oceanography in the northern South China Sea from June to July of 2009, and conducted a 1-day observation from 15:40 of June 24 to 16:40 of June 25 using a chain of instruments, including temperature sensors, pressure sensors and temperature-pressure meters at a site (117.5A degrees E, 21A degrees N) northeast of the Dongsha Islands. We measured fluctuating tidal and subtidal properties with the thermistor-chain and a ship-mounted Acoustic Doppler Current Profiler, and observed a large-amplitude nonlinear internal wave passing the site followed by a number of small ones. To further investigate this phenomenon, we collected the tidal constituents from the TPXO7.1 dataset to evaluate the tidal characteristics at and around the recording site, from which we knew that the amplitude of the nonlinear internal wave was about 120 m and the period about 20 min. The horizontal and vertical velocities induced by the soliton were approximately 2 m/s and 0.5 m/s, respectively. This soliton occurred 2-3 days after a spring tide.

Vertical structure and evolution of the Luzon Warm Eddy

Eddies are frequently observed in the northeastern South China Sea (SCS). However, there have been few studies on vertical structure and temporal-spatial evolution of these eddies. We analyzed the seasonal Luzon Warm Eddy (LWE) based on Argo float data and the merged data products of satellite altimeters of Topex/Poseidon, Jason-1 and European Research Satellites. The analysis shows that the LWE extends vertically to more than 500 m water depth, with a higher temperature anomaly of 5A degrees C and lower salinity anomaly of 0.5 near the thermocline. The current speeds of the LWE are stronger in its uppermost 200 m, with a maximum speed of 0.6 m/s. Sometimes the LWE incorporates mixed waters from the Kuroshio Current and the SCS, and thus has higher thermohaline characteristics than local marine waters. Time series of eddy kinematic parameters show that the radii and shape of the LWE vary during propagation, and its eddy kinetic energy follows a normal distribution. In addition, we used the empirical orthogonal function (EOF) here to analyze seasonal characteristics of the LWE. The results suggest that the LWE generally forms in July, intensifies in August and September, separates from the coast of Luzon in October and propagates westward, and weakens in December and disappears in February. The LWE's westward migration is approximately along 19A degrees N latitude from northwest of Luzon to southeast of Hainan, with a mean speed of 6.6 cm/s.