Synthesis And Characterization Of Organolanthanide Complexes Supported By β-Diketiminates And Their Behavior For Reaction

A series of lanthanide complexes supported by p-diketiminates were synthesized, and fully characterized. Among of them, 14 complexes were characterized by X-ray diffraction analysis. Some of these complexes showed good catalytic activity for the polymerization of methyl methacrylate and caprolactone.1. Reactions of ?diketiminate lithium 2,6-Me2C6H3NCMe2CH]Li L'Li with LnCl3 in 1:1 molar ratio gave LILnCl(THF)(|a-Cl)2Li(THF)2 (Ln = Tb (1), Eu (2), Yb (3), Nd (4), Sm (5)). Recrystallization of complexes3, 4 and 5 in toluene afforded the neutral lanthanide complexes L'LnCl2THF)2 (Ln = Yb(6), Nd(7), Sm(8)). Further recrystallization of complexes 6 and 8 in hot toluene afforded L'LnClCfi-COsLn Ll(THF) (Ln = Yb(9), Sm(10)). Treatment of the mother liquor of complex 5 in hot toluene for two times gave the novel trinuclear complex L2SmCl(?Cl)3SmLVCl)Li(L2H)(THF) (11), in which a neutral p-diketimine is incorporated with LiCl. All of these complexes were characterized by elemental analysis, IR spectroscopy and melting point determination. Crystal structures of complexes 1-3, 6, 9 and 11 were obtained. The luminescence properties of complexes 1 and 2 were investigated.2. Reaction of ?diketiminate lithium 2,6-Pri2C6H3)NC(MeCH]Li (L2Li) with YbCb in 1:1 molar ratio, crystallized from DME/toluene mixed solvents, gave the complex L2YbCl2(DME) (12). Reaction of L2YbCl2(THF)2 with LiNPrs2 in 1:1 molar ratio in toluene, crystallized from toluene gave the neutral complex [L2YbNPr'2(u-Cl)]2 (13); if crystallization from THF/toluene mixed solvents, the "ate" complex L2YbNPri2(j4.-Cl)2(Li)(THF)2 (14) can be obtained. Reactions ofL2YbCl2(THF)2 with LiNPh2 or LiC5H,0 in 1:1 molar ratio gave L2YbClNPh2(THF) (15) and [L2YbNC5Hio(u-Cl)]2 (16) respectively. L2YbCl2(THF)2 reacted with LiNPh2 in 1:2 molar ratio to produce the complex L2Yb(NPh2)2 (17). All these complexes were characterized by elemental analysis, IR spectroscopy, and X-ray diffraction.3. Divalent complexes L2YbR(THF) (R = C9H7 (18), CH3C5H4 (19), 2,6-Bu'2-4-MeC6H20 (20)) were synthesized by reducing L2YbRCl with Na-K alloy. Their catalytic behaviors for the polymerization of MMA were tested and it was first found that divalent p-diketiminate lanthanide complexes can catalyze the polymerization of MMA in moderate activity.4. The catalytic behaviors of complexes 13, 15 and 16 for the polymerization of MMA and e-caprolactone were tested. It was found that these three complexes can effectively catalyze the polymerization of MMA and the polymerization gives syndiotactic-rich PMMA. They are active for the ring opening polymerization of s-caprolactone to give the PCLs with narrow molecular weigh distributions.5. Reaction of 2,4-pentanedione with 4-methyl-2-aminophenol give a new type of ketoimine: [CH3COCHC=NC6H4OH(4-CH3)] (L3H2). Reactions of L3Li2 with LnCl3 in THF, after crystallized from THF/DME, afforded [L3LnCl(DME)]2 (Ln = Yb (21), Tb (22), Y (23)). All these complexes were characterized by elemental analysis, IR spectroscopy. Crystal structures of complexes 21 and 22 were determined.