| A series of lanthanide dichloride, chloride, aryloxide and methylcyclopentadienyl complexes supported by bidentate or tridentate Schiff base ligand [( 3,5-But2-2-(OH) C6H2CH=N-8-C9H6N(HL1), 3,5-But2-2(OH)-C6H2CH=N-4-R-C6H4, R= -Cl (HL2), -CH3 (HL3), -F (HL4)] were synthesized and well characterized, including monometallic dichloride, chloride, aryloxide and methyl-cyclopentadienyl, as well as a ytterbium and samarium complexes bearing an unprecedented dimeric or trimeric polyanionic ancillary ligands. The catalytic activity of these complexes in polymerization ofε-caprolactone, guanylation of amines with carbodiimides and cyclotrimerization of phenyl isocyanat respectively was tested. The main results obtained are as follows:1. The treatment of salicylaldimine 3,5-But2-2-(OH)C6H2CH=N-8-C9H6N (HL1) and NaH in 1:1 mole ratio in THF yielded the sodium salt of salicylaldimine {(3,5-But2-2-(O) C6H2CH=N-8-C9H6N) Na(THF)}2 (2) in good yield. The complex was characterized by elemental analysis, 1HNMR spectroscopy and X-ray diffraction. The crystal structural analysis of (2) revealed that it had a dimeric structure .2. The in situ generated 2 from the treatment of the mixture of NaH with 1 equiv HL1 in THF reacts with 1/3 equiv of LnCl3 (Ln = Sm, Eu) to give the monomeric lanthanide Schiff base complexes (3,5-But2-2-(O)C6H2CH=N-8- C9H6N)3Sm (C6H14) (6) and (3,5-But2-2-(O) C6H2CH= N-8-C9H6N)3 Eu(C4H8O) (C6H14) 0.5(7) in good yield, respectively. The X-ray diffraction analysis showed that the atoms of Sm and Eu were nine-coordinate. The in situ generated [3,5-But2-2 (OH)-C6H2CH=N-4-R-C6H4]Na (R= -Cl (HL2), -CH3 (HL3), -F (HL4) from the treatment of the mixture of NaH with 1 equiv 3,5-But2-2(OH)-C6H2CH=N-4-R-C6H4 (R= -Cl (HL2),-CH3 (HL3),-F (HL4) in THF reactions with 1/3 equiv. of SmCl3 to give the monomeric samarium Schiff base complexes(3,5-But2-2-(O)-C6H2CH= N-4-Cl-C6H4)3Sm(C4H8O) (8),(3,5-But2-2-(O)-C6H2CH =N-4- CH3-C6H4)3Sm (C6H14) 0.5 (9), (3,5-But2-2-(O)-C6H2CH =N-4-F-C6H4)3Sm(C4H8O) (10), respectively. The complexes 8 and 9 were determined by X-ray diffraction. These complexes can catalyze the polymerization ofε-caprolactone, guanylation of amines. The electron-withdrawing group on the Schiff base ligand can increase the activity of samarium complexes: the active sequence is Cl > F > CH3. Bidentate Schiff base complexes exhibited much higher reactivity than the tridentate Schiff base complexes.3. The in situ generated 2 from the treatment of the mixture of NaH with 1 equiv HL1 in THF reacts with 1 equiv. of LnCl3 (Ln =Yb, Sm, Eu, Y) to give the lanthanide Schiff base dichloride complexes (3,5-But2-2-(O) C6H2CH=N-8-C9H6N)YbCl2(DME) (11a), (3,5-But2-2-(O) C6H2CH= N-8- C9H6N)SmCl2(DME) (12), (3,5-But2-2-(O) C6H2CH=N-8-C9H6N)EuCl2(DME)(13) and (3,5-But2-2 -(O) C6H2-CH=N-8-C9H6N) YCl2(DME)(14), respectively. The complex 11a was determined by X-ray diffraction. The crystal structure revealed the Complex 11a had a solvated monomeric structure, and the central metal ytterbium atom was seven-coordinated. In contrast, a complex ((3,5-But2-2-(O)C6H2CH= N-8-C9H6N)YbCl3)(Li(DME)3(11b) was prepared when lithium salt from the treatment of the mixture of LiBu with 1 equiv. HL1 in THF was used instead of the sodium salt of HL1 . In anion, the central metal Yb was six-coordinated.4. Reaction of 11a, 12, 13 and 14 with NaCH3C5H4 in 1:1 molar ratio, respectively, gave the complexes (3,5-But2-2-(O)C6H2CH=N-8-C9H6N)LnCl (CH3C5H4)(THF)(Ln =Yb(15), Sm (16), Eu(17), Y(18)). The complexes 15, 16, and 17 had been characterized by X-ray diffraction. The structural analysis showed that three complex had isostructural complexes. Reaction of complex 11a with 2 equiv. of Na(OC6H3-But2-2,6) in THF afforded the desired solvent-free ytterbium aryloxide [(3,5-But2-2-(O)C6H2CH= N-8-C9H6N)Yb(OC6H3-But2-2,6)2] (19). Complex 19 can also be prepared by the protolytic exchange reaction of HL1 with (OC6H3-But2-2,6)3Yb in 1:1 molar ratio. The structural analysis showed Yb atoms was five-coordinated distorted trigonal bipyramidal geometry.5. The in situ generated 2 from the treatment of the mixture of NaH with 1 equiv 3 in THF reacts with 1 equiv. of LnCl3 (Ln =Yb, Sm, Eu) to give the lanthanide Schiff base chloride complexes {(3,5-But2-2-(O)C6H2CH=N-8-C9H6N)}2LnCl(C4H8O) 3.5 (Ln =Yb(20), Sm(21), Eu(22)), respectively. The complex 20 was determined by X-ray diffraction. Reaction of complex 20 with 1 equiv. of Na(OC6H3-But-2-Me-4) in THF afforded the desired ytterbium aryloxide [(3,5-But2-2-(O)C6H2CH= N-8-C9H6N ) 2Yb(OC6H3-But2-2,6) (THF) 2.5 (21). The structural analysis showed that the coordination geometry around ytterbium atom can be described as a distorted pentagonal bipyramid. Reaction of complex 20 with 1 equiv. of (CH2=CH-CH2)MgBr in THF afforded the [Mg(H2N -8-C9H6N) Cl(THF)3]Br (24).6. Reaction of the Schiff base HL1, LiBun, YbCl3 and Na(OC6H3-But-2-Me-4) in 2:2:1:1 molar ratio afforded an unprecedented ytterbium aryloxide (3,5-But2-2-(O) C6H2CH =N-8-C9H6N) (3,5-But2-2-(O) C6H2CH(C4H9) -NH-8-C9H6N)Yb (OC6H3-But-2 -Me-4)(C7H8)2.5 (25). Complex was fully characterized by elemental analysis and X-ray diffraction.7. The reaction of Yb[N(TMS)]3 with Schiff base HL1 in 1:3 molar ratio afforded the Schiff base ytterbium (III) complex (3,5-But2-2-(O)C6H2CH= N-8-C9H6N)3Yb(C4H8O)4 (26). However, reaction of Yb[N(TMS)]3 with HL1 in 1:1 molar ratio afforded an unprecedented ytterbium (III) complex YbL1``2(28), in which two Schiff base HL1 were dimerized to form the new ligand H3L1``2 by the reductive coupling reactions of imine groups involving a rare coupling reaction of C=N bond of quinoline ring with imine group of Schiff base ligand.8. The reaction of Yb(II)[N(TMS)]2 with Schiff base HL1 in 1:3 molar ratio also afforded the Schiff base ytterbium (III) complex (26). Treatment of complex 21 with excessive metallic sodium produced an unprecedented samarium complex [Na(DME)3][SmL1`3Na(DME)] (27), in which three Schiff base HL1 were trimerized to form the new ligand H5L1`3 by the reductive coupling reactions of imine groups also involving a rare coupling reaction of C=N bond of quinoline ring with imine group of Schiff base ligand.
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