| Some neutral lanthanide complexes supported by carbon-bridged bis(aryloxide) were synthesized and well characterized. The catalytic behavior of these complexes for the ring-opening polymerization ofε-caprolactone was studied. The ligands used are 2,2'-methylene-bis(6-tert-butyl-4-methylphenoxo), abbreviated as MBMP.1. Reaction of LnCp3 with MBMPH2 in THF in a 1:1 molar ratio afforded neutral complexes (MBMP)LnCp(THF)2 (Ln = Nd(1), Y(2), Yb(3), Sm(4), La(5)). These complexes were well characterized, and the crystal structures of 1, 2, and 4 were determined. These complexes can initiate the polymerization of　-caprolactone.2. Reaction of (MBMP)LnCp(THF)2 with ArOH in THF in 1:1 molar ratio afforded neutral complexes (MBMP)Ln(OAr1)(THF)3 (Ar1O = 2,6-iPr-C6H2O, Ln = Yb (6), Sm (7), La (8)), (MBMP)Ln(OAr2)(DME)2 (Ar2O = 2,6-Me-C6H2O, Ln = Yb (9), Sm (10), La (11)), [(MBMP)Ln(OAr3)(THF)2]2 (Ar3O = p-tBu-C6H2O, Ln = Nd (12), Sm (13), La (14)), (MBMP)Ln(OAr4)(THF)3 (Ar4O = 2,4,6- (Me2NCH2)3 C6H2O, Ln = Yb (15), Sm (16), La (17)). The crystal structure of complexes 7, 10, 11 and 12 was determined. Complexes 7, 10, 12 and 16 can effectively initiate the ring-opening polymerization ofε-caprolactone.3. Reaction of (MBMP)LnCp(THF)2 with MBMPH2 in toluene in a 1:1 molar ratio afforded the neutral homoleptic complexes (MBMP)Ln(MBMPH)(THF)2 (Ln = Y (18), Sm (19)) and (MBMP)3La2(THF)2 (20). These complexes were characterized by IR, elemental analysis and 1HNMR, and the crystal structures of 18 and 20 were determined. Complexe 20 is a highly efficient initiator.
|
PDF Full Text Request