The neodymium chloride complex[Nd（ONN＇O）Cl（THF）]2 supported by amine-bis（phenolate） ligand was synthesized by the metathesis reaction of anhydrous NdCl3 with Li2（ONN＇O）[H2ONN＇O = Me2NCH2CH2N（CH2-3-Bu2^t-5-Me-C6H2OH）2]in high yield.X-ray structural determination shows[Nd（ONN＇O）Cl（THF）]2 complex consists of two seven-coordinate neodymium centers linked throughμ-Cl bridges.And this complex was successfully used to initiate the ring-opening polymerization（ROP） ofε-caprolactone.
Li Rong Wang Zhen Hua Liang Xu Feng Ni Zhi Quan Shen
The poly（2,2-dimethyltrimethylene carbonate） （PDTC） with one hydroxyl and one formate terminal functions was synthesized by in situ generated, tetrahydrosalen stabilized yttrium borohydride complex. The influences of monomer/initiator molar ratio, temperature and reaction time on polymerization of DTC were investigated. Under the condition： [DTC]/[I] = 500, 55℃, toluene： 0.5 mL, DTC： 0.6 g, PDTC with Mn = 15600 and PDI = 2.15 was obtained. Through 1H-NMR and 13C-NMR analyses, the structure of PDTC was characterized and a coordination-insertion mechanism was proposed. In addition, the random copolymerization of DTC and caprolactone （CL） initiated by rare-earth borohydride compound was studied. The microstructure of PDTC-co-PCL includes four diads： DTC-CL, CL-CL, DTC-DTC and CL- DTC, which were determined by the specific signals in lH-NMR spectra. Based on the typical signals of the formate （δ = 8.08） and hydroxyl （δ= 3.34） end groups of PDTC-co-PCL, a mechanism involving DTC monomer inserts before CL during the initiation process was presumed. Furthermore, the thermal properties of amorphous copolymer were characterized by differential scanning calorimetry （DSC）. The results support the random structure of PDTC-co-PCL.
Tetrahydrosalen ligand was employed in the synthesis of gadolinium complex. The ligand was deprotoned by LiBu, and the afforded lithium salt was reacted with anhydrous GdCl3 to produce the gadolinium complex through salt metathesis. This complex was successfully used to initiate the ring-opening polymerization of ε-caprolactone. The initiation conditions in different temperature, monomer-to-initiator ratio and time were investigated. Under the condition： [ε-caprolactone]：[catalyst] = 600, 56 ℃, toluene： 2 ml, poly（ε-caprolactone） （PCL） with Mw = 11,2782 and PDI = 1.96 was achieved.
Guang Ming Wu Xu Feng Ni Wei Lin Sun Zhi Quan Shen
In this paper, we report the preparation of a new tertrahydrosalen-stabilized yttrium complex which was employed as an initiator-precursor for the polymerization of ε-caprolactone （ε-CL） in the presence of NaBH4 to give interesting hydroxytelechelic poly（ε-caprolactone） （PCL）. The effect of [monomer]/[initiator] （[CL]/[I]）, temperature and time on the polymerization was investigated. It was found that under the condition： [CL]/[I] = 1200, 55℃, toluene： 0.5 mL, ε-CL： 0.5 mL, PCL with Mw = 32,600 and PDI = 1.47 was obtained.
Jing Huang Jian Fang Yu Guang Ming Wu Wei Lin Sun Zhi Quan Shen
Neodymium-based heterocyclic Schiff base complex was prepared and applied for the coordination polymerization of isoprene. This complex polymerized isoprene to afford products featuring high cis-1,4 stereospecificity （ca. 95%） and high molecular weight （ca, 10^5） in the presence of the triisobutyl aluminium （AliBu3） as cocatalyst, The microstructure of obtained polyisoprene was investigated by FTIR, 1^H NMR. Two different kinds of active centers in the catalyst system were examined by GPC method.
An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,monomer concentration,polymerization time and temperature were investigated.Activities of ca.171 kg/Nd·h were obtained under the optimum condition(CL/Nd=1600(molar ratio),[CL]=2.26 mol L^(-1),1 h at 50℃),giving a poly(ε-caprolactone)(PCL)of number-average molecular weight M_n=5.4×10~4 and molecular...
