| 12 divalent organolanthanides supported by C5H4CMe2Ph- (Cp) or chelating bisphenolate ligand such as 2,2 -CH2(Me-4-But-6-C6H3O)2 were first synthesized and well characterized. The catalytic behaviors of some organolanthanides mentioned above for polymerizations of ε-caprolactone (CL), MMA, 2,2-dimethyltrimethylenecarbonate (DTC) and copolymerization of ε-CL with DTC were tested. Besides, 7 trivalent lanthanide complexes were prepared and their catalytic activities on the oligomerization of phenyl isocyanate were examined. The coupling reactions of carbodiimides with divalent lanthanide complexes were studied for the first time.1. The reaction of LnI2(THF)2 (THF = tetrahydrofuran) with 2 equivalent of PhMe2CC5H4Li(DME) in THF affords the divalent lanthanide complexes [Ln2(PhMe2CC5H4)4(u-I)2][Li(DME)3]2 (Ln = Sm (2), Yb (3)), while the Na/K alloy reduction of (PhMe2CC5H4)2YbCl, which was formed in situ by the reaction of YbCl3 and PhMe2CC5H4Li in 1:2 molar ratio, gives Yb(II) complex [Yb2(PhMe2CC5H4)4(u-Cl)2][Li(DME)3]2(4). All the complexes were fully characterized by elemental analysis, IR spectroscopy, 1H-NMR, and X-ray diffraction. The single-crystal structural analyses of 2-4 reveal that they all comprise two Li+(DME)3 cations and a new class of dianion, {[C5H4(CMe2Ph)]4Ln2(u-X)2}2-, in which two [C5H4(CMe2Ph)]2Ln were bridged together by two iodine atoms or two chlorine atoms. The central metal is bound to two C5H4PhCMe2 in a n5-manner and two halogen atoms to form the formal coordination number of 8. The geometry around the central metal is best described as a pseudo-distorted tetrahedral. Each lithium atom in the cations is coordinated to three DME molecules and adopts a distorted-octahedralgeometry. 2-4 are first examples of dinuclear divalent lanthanide complexes containing organolanthanide dianion.2. 2-4 are efficient single-component initiators for the ring-opening polymerization of ?-CL. The Sm species shows higher activity than that of Yb, and 4 containing chlorine bridges is more active than that of 3 containing iodine bridges.3. 2-4 are active for the polymerization of MMA to give syndiotactic-rich polymers with relatively narrow molecular weight distribution (<1.9), and they all display higher activity than that of the neutral species (ButC5H4)2Sm(DME).4. The metathesis reaction of SmI2(THF)2 with two equivalents of 2,6-But2C6H3ONa in the mixed solution of THF and DME gives (2,6-But2C6H3O)2 Sm(DME)2(6), and its crystal structure was determined by X-ray diffraction.5. Ln[N(SiMe3)2]2(THF)3 reacts with 1 equiv of 2,2'-methylene bis(6-tert-butyl-4-methyl-phenol) (L1H2) or 2,2'-ethylidene bis(4,6-di-tert-butyl-phenol) (L2H2) in toluene to give quantitatively a new class of bridging biphenolate lanthanide(II) complexes [LnL1(THF)n]2 (Ln = Sm, n = 3 (7); Ln=Yb, n=2 (8)) and [LnL2(THF)3]2 (Ln = Sm (13); Ln = Yb (14)). Because of poor solubility in polar solvent such as THF, addition of hexamethylphosphoric triamide(HMPA) to a THF solution of 7 , 8 and 13 afforded the corresponding HMPA-coordinated complexes, [LnL1(HMPA)m(THF)n]2(Ln = Sm, m=1, n=1(9); Ln=Sm, m = 2, n =0(10); Ln=Yb, m =1, n = 1 (11)) and [SmL2(HMPA)2]2 (15) respectively, in excellent yields. "One-pot" reaction of EuCl2(THF)3 with sodium salts of the bisphenolate followed by reduction with the excessive Na-K alloy, led to the formation of the divalent analogue{EuL1(HMPA)2}}2 (12). The formula of 7-15 are confirmed by elemental analyses and NMR spectra. 10-12 and 15 were further characterized by X-ray diffraction. The crystal structures reveal them to be a homoleptic dimeric complex possessing two oxygen bridges.6. The results of ring-opening polymerization of e -CL by 6-13 and 15 indicate they are effective initiators, but the activities of them are lower than that of monodentatearyloxide lanthanide(II) complex. This may be caused by the dimeric structure. The activity order of the lanthanide(II) bisphenoxides is consistent with the red...
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