A new dianionic guanidinate bridged diamide ytterbium(Ⅲ) complex {[Me2Si(NPh)2]2Yb[(NiPr)2CN(SiMe3)2]}{Li(THF)2}2 was synthesized by the reaction of bisguanidinate ytterbium chloride [(SiMe3)2NC(NiPr)2]2Yb(μ-Cl)2Li(THF)2 with silylene-bridged diamide lithium PhLiNSiMe2NLiPh.The complex was characterized by elemental analysis and IR.The molecular structure was further determined by X-ray diffraction techniques.The crystals are monoclinic,space group p 21/c,a=14.0001(8),b=17.6808(9),c=24.9565(16),β=95.994(3),V=6143.8(6)3,Dc=1.287 g/cm3,Z=4.
The catalytic activity of a series of indenylnickel（Ⅱ） halides： （1-R-Ind）Ni（PPh3）X （R=ethyl, cyclopentyl and benzyl, while X=Cl, Br and I）, towards styrene polymerization was studied in the presence of NaBPh4 and PPh3. The catalytic property of these halides was related to the substituent group on the indenyl ligand and the halogen atom bonded to the metal atom. Among them, the （1-Et-Ind）Ni（PPh3）Cl/NaBPha/PPh3 system showed the highest activity for the polymerization of styrene, and the polystyrene obtained was a syndio-rich （rr triad） atactic polymer with Mn values in the range of 103--104. The mechanism of the styrene polymerization initiated by the （1-Et-Ind）Ni（PPh3）Cl/NaBPha/PPh3 system was studied.
A homoleptic lanthanide guanidinate complex [（CH2）5NC（NiPr）2]3Yb was synthesized by the metathesis reaction of lithium guanidinate with anhydrous YbCl3 in 3∶1 molar ratio in THF.Its crystal structure was determined by X-ray diffraction.The crystallographic data:C36H72N9Yb,Mr=804.07,orthorhombic,space group P212121（#19）,a=10.3168（7）,b=11.443（7）,c=35.5649（2）?,V=4199.1（5）?3,Z=4,Dc=1.272 g/cm3,F（000）=1684.00,T=193.1K,λ（MoKα）=0.7107?,μ=22.61 cm-1,R=0.040,wR=0.126 for 8653 observed reflections with（I>3.00 σ（I））.The ytterbium is six-coordinate by six nitrogen atoms of three chelation bidentate guanidinate ligands.
Cp2Yb·2THF reacts with CpNa in 1:1 molar ratio in THF at 40℃ for 2 h, and the in situ generated ani-onic divalent complex NaYbCp3(THF)n reacts further with an excess of CpH at 40℃ for 48 h, after work-up, affording the trivalent anionic ytterbium complex [Na(THF)2(μ2-η5-Cp) (η5,η5,η1-Cp3Yb)(THF)]n (1) by oxidation reaction of Cp2Yb with CpH. Crystal structure determination reveals that com-plex 1 has one-dimension polymeric chains of distinct Na(THF)2(μ2-η5-Cp)(η5,η5,η1-Cp3Yb)(THF) units, which were formed by the coordination of the bridging Cp ligand with Cp3Yb·THF and Na(THF)2 in η5,η5 mode via self-assembly.
Samarium diiodide （SmI2） was found to be an efficient catalyst for the condensation of o-phenylenediamine and ketones to afford the corresponding 2,3-dihydro-1H-benzo[b][1,4]-diazepines in moderate to excellent yields under very mild and solvent-free conditions. The real active species here was suggested to be a Sin（Ⅲ） intermediate formed in situ and the mechanism of the present reaction was proposed.
