Polymerization of N-Phenylmaleimide Catalyzed by (ArO)_2Sm(THF)_4

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Synthesis and Characterization of the First Dinuclear Europium （Ⅱ） Complex Supported by Carbon-Bridged Biphenolate Ligand

Amongpossiblealternativestothetraditionalan cillaryligandbis(cyclopentadienyl)setinrareearth metalchemistry,alkoxides(aryloxides)havereceived muchattentionandbecomeincreasinglypopularsince theyareeasilyavailable,tunableandevenpotentially recyclableancillarysetsformediatingthereactivityof theseelectropositivecations[1,2].Thechelatebiphenol andbinaphtholhavebeenfoundtobeabletoactasa dianionicligandintherareearthchemistry,whichhas theadvantagesofavoidingligandredistributionreac tions,andallowingth…     

Synthesis, Crystal Structure of [ （MeC5H4）2Ln（μ-OCH2 CH2NMe2 ） ]2 （Ln = Sm, Y, Nd） and Their Catalytic Activity for Ring-Opening Polymerization of ε-Caprolactone

Reaction of (MeC5H4)3Ln with HOCH2CH2NMe2 in tetrahydrofuran (THF) gives the new complexes [ (MeC5H4)2Ln(μ-OCH2CH2NMe2)]2(Ln = Sm, Y, Nd) with nitrogen functionalized μ-alkoxide ligand. The complexes were characterized by elemental analysis and IR, and [ (MeC5H4)2Sm(μ-OCH2CH2NMe2)]2 was structurally characterized by the X-ray diffraction to be a dimer formed by two unsymmetric oxygen bridges. The complex has a tricyclic skeleton with the additional two Sm- N bonds via intmmoleeular coordination of OCH2CH2NMe2. The coordination number of the central metal Sm is nine. The tide complexes show good catalytic activity for ring-opening polymerization of ε-capmlactone.     

Reaction of Bis （Methylcyclopentadienyl） Lanthanide Amido Complex with n-Hexyl isocyanate-Synthesis and Characterization of {（MeC5H4 ）2 Yb[ OC（NPh2 ）N（n-hexyl） ]}2

In recent years,the synthesis of polyisocyanatesand their chemical structures have received consider-able attention,because polyisocyanates have somespecial properties,such as chiral spiral structure[1]and liquid crystal[2]etc.We previously reported thatcyclopentadienyl lanthanide amido complexes[3]anddivalent lanthanide complexes[4]both can catalyze theoligomerization or polymerization of phenyl isocyanate.Furthermore,the active intermediates of these reac-tions were obtained by the stoichiom…     

GW-CF低残渣压裂液体系

GW-CF低残渣压裂液体系,是针对油气田酸化压裂作业中低渗透率地层而自主研发的一种低残渣、低浓度、高返排的压裂液体系。该体系包括低残渣增稠剂和5个配套助剂,通过低残渣瓜尔胶增稠剂分子结构设计和高效、易控合成工艺及低浓度瓜尔胶有效交联等独创技术实现,具有使用浓度低、携砂能力强、滤失量小、摩阻低、返排率高、增产效果好等优点,满足了低渗透油气藏的经济、高效开采的需要,具有广阔的应用前景。     

Synthesis and Characterization of A Polynuclear Yttrium Trifluoroethoxide and Its Activity for Oligomerization of Phenyl Isocyanate

A polynuclear yttrium trifluoroethoxide was synthesized and its activity for the oligomerization of phenyl isocyanate was tested. Reaction of anhydrous YCl3 with CF3CH2ONa in a 1:3 molar ratio in THF at room temperature, after workup, gave complex 1 as colorless crystals. The composition of complex 1 is [Y(OCH2CF3)3]6ONa2(THF)12, which was identified by elemental analysis and 1H NMR. Further X-ray structure determination reveals that complex 1 is a polynuclear ion pair compound, [Y6(μ6-O)(OCH2CF3)18]2-[Na(THF)6] 2 (1). The crystal data of complex 1 are trigonal, P-3 space group, a=1.78440(14) nm, b=1.78440(14) nm, c=1.27395(12) nm, γ=120°, V=3.5129(5) nm3, Z=1, Dc=1.607 mg·m-3, μ=2.591 mm-1 (Mo Kα), F(000)=1710, R=0.067, wR=0.182. Preliminary results demonstrated that complex 1 is a highly effective catalyst for the oligomerization of phenyl isocyanate.