| The thesis focused on the reactivity and coordination chemistry of the rare-earth metal amido complexes with 2-amino-functionalized indolyl compounds.The catalytic activity of the resulting new rare-earth metal complexes with indolyl ligands were also studied.The thesis contains the following parts:1)the reactivities of the rare-earth metal amido complexes with different 2-amino-functionalized indolyl compounds,and the proposed pathway of the dehydrogenation and redox reaction between the rare-earth metal amido complexes and the functionalized indoles;2)the catalytic activity of the resulting rare-earth metal complexes for the intramolecular hydroamination of aminoalkenes and the polymerization of isoprene.The details are listed as follows.1.Reactivities of the rare-earth metal amido complexes with2-amino-functionalized indolyl compounds,and the proposed pathway of the dehydrogenation and redox reaction between the rare-earth metal amido complexes and the functionalized indoles(1)Reactivities of the rare-earth metal amido complexes with2-aromaticamino-functionalized indolyl compoundsReaction of amino-functionalized indole 2-(2,6-'Pr2C6H3NHCH2)C8H5NH(1)with[(Me3Si)2N]3Eu(?-Cl)Li(THF)3 led to oxidative dehydrogenation of secondary amine to imine with a reduction of europium(?)to europium(?)and isolation of the europium(II)complex {[?-?6:?1:?1-2-(2,6-iPr2C6H3N=CH)C8H5N]Eu[2-(2,6-iPr2C6H3 N=CH)C8H5N]}2(2)having the imino-functionalized indolyl ligand bonded to the metal ion in the novel ?-?6:?1:?1 modes.Reaction of[(Me3Si)2N]3RE(?-Cl)Li(THF)3]with 2-(2,6-iPr2C6H3NHCH2)C8H5NH(1)generated the novel dinuclear complexes{[?-?5:?1:?1-2-(2,6-'Pr2C6H3NCH2)C8H5N]RE[N(SiMe3)2]}2(RE = Sm(3),Nd(4))and the mononuclear complexes[?1:?1-2-(2,6-iPr2C6H3NCH2)C8H5N]RE[N(SiMe3)2]-(THF)2(RE = Yb(5),Y(6),Er(7),Dy(8))incorporating amido-appended indolyl ligands,with no observation of the dehydrogenation of secondary amine to imine and the reduction of RE3+ to RE2+.However,treatment of[(Me3Si)2N]3Yb(?-Cl)Li(THF)3]with compound 1 at the elevated temperature(refluxing toluene)afforded the ytterbium(?)complex[2-(2,6-iPr2C6H3N=CH)C8H5N]2Yb?(THF)2(9)with oxidative dehydrogenation of secondary amine to imine and the reduction of Yb3+ to Yb2+ as well.When[(Me3Si)2N]3Y?(?-Cl)Li(THF)3 reacted with compound 1 in refluxing toluene afforded the complex[2-(2,6-'Pr2C6H3N=CH)C8H5N]3Y(10)with oxidative dehydrogenation of secondary amine to imine.In addition,reaction of 2-(C6H5NHCH2)C8H5NH(11)with[(Me3Si)2N]3Eu(?-Cl)Li(THF)3 gave the complex[2-(C6H5N=CH)C8H5N]2Eu[N(SiMe3)2](12)with bis(imino-funnctionalized idolyl)ligands,and with no observation of the reduction of Eu3+ to Eu2+.Furthermore,the reactivities of the new indolyl complexes with the formamidines(2,6-R2C6H3)N=CHN(C6H3R2-2,6)were investigated with isolation and characterization of europium(?)complexes in novel bonding modes{[?-?2:?1:?1-2-(2,6-iPr2C6H3N=CH)-C8H5N]Eu[(2,6-iPr2C6H3)N=CHN(C6H3iPr2-2,6)](THF)}2(13),{[?-?3:?1:?1-2-(2,6-iPr2C6H3N=CH)C8H5N]Eu[(2,6-Me2C6H3N=CHN-(C6H3Me2-2,6)](THF)}2(14),[?1:?1-2-(C6H5NHCH2)C8H5N]Eu[(?3-2,6-iPr2C6H3)N=CHN(C6H3iPr2-2,6)][N(SiMe3)2](15).The results suggested that the steric hindrance of organic molecules has a great influence in the reactivity and coordination of the rare-earth metal ions with the functionalized indolyl ligand.(2)Reactivities of the rare-earth metal amido complexes with 2-alkylamino-functionalized indolesReactions of alkylamino-functionalized indole 2-(tBuNHCH2)C8H5NH(17)with[(Me3Si)2N]3RE(?-Cl)Li(THF)3 afforded the complexes[?1:?1-2-(tBuN=CH)C8H5N]RE[N(SiMe3)2]2(RE =Er(18),Y(19),Dy(20),Eu(21),Sm(22),Nd(23))and[?1:?1-2-('BuN=CH)C8H5N]2Yb[N(SiMe3)2](24)incorporating the 2-imino-functionalized indolyl ligands with the dehydrogenation of secondary amines to imines.In addition,reaction of 2-imino-functionalized indolyl yttrium complex with PhC?CH produced the novel complex{[?1:?1-2-('BuN=CH)C8H5N]2Y(?-?2:?1-C?CPh)}2(27)with the alkynyl bonded to the rare-earth metal ion in novel ?-?2:?1 manners,along with the activation of sp C-H bond of terminal alkyne.(3)The proposed pathway of the dehydrogenation and redox reaction between the rare-earth metal amido complexes and the 2-amino-functionalized indolesThe above results indicated that the redox potentials of Ln3+/Ln2+ and steric hindrance of the 2-amino-functionalized indoles were crucial for the dehydrogenation and redox reaction between 2-amino-functionalized indoles and rare-earth metal amides,which were significantly affected by the reaction temperature.Based on the above results,the pathway for the formation of imino-functionalized indolyl rare-earth metal(?)complexes was proposed.Reaction of the 2-amino-functionalized indole with[(Me3Si)2N]3RE(?-Cl)Li(THF)3 first affored the amido-appended indolyl rare-earth complexes via the silylamine elimination.As the key intermediates,the amido-appended indolyl complexes underwent ?-H elimination then a fast acid-base exchange with HN(SiMe3)2 to give the complexes having the imino-functionalized indolyl ligand,which underwent ligand redistribution followed by homolysis of the RE-N bond to afford the final redox product with the dehydrogenation of the 2-amino-functionalized indoles.2.The intramolecular hydroamination of aminoalkenes catalyzed by the new rare-earth metal complexes with amino-and imino-functionalized indolyl ligandsThe intromolecular hydroamination reaction of aminoalkenes catalyzed by the new rare-earth metal complexes with amido-or imino-functionalized indolyl ligands was first studied.It is found that the rare-earth metal complexes 5-8,18-23 with mono indolyl ligand were active for the intramolecular hydroamination of aminoalkenes.A series of aminoalkenes substrates were smoothly converted to the cyclic products with a high conversion under mild conditions with a low catalyst loading(2-5 mol%),but different substrates shows different activities.The formation of six-member ring product is more difficult than that of five-member ring.For the substrates with internal alkenes,the catalytic transformations require a higher catalyst loading and prolonged reaction time.The reaction rate is enhanced for the substrates containing bulky phenyl substituents at the ?-position to the amino group.The conversion of the a-monosubstituted aminoalkene,having amino group at secondary carbon,is also completed with an albeit moderate diastereoselectivity.It is also found that the catalytic activity of bisindolyl complexes 12,24 was very poor,and the activity of the amino-functionalized indolyl complexes was better than those with imino-functionalized indolyl ligand(complex 6>19,7>18,8>20).The dinuclear complexes 3 and 4 displayed the highest catalytic activity among these catalysts.3.The polymerization of isoprene catalyzed by the new rare-earth metal complexes with 2-functionalized indolyl ligandsThe polymerization of isoprene catalyzed by the dinuclear amido-functionalized indolyl neodymium complex and the 2-functionalized indolyl rare-earth metal complexes was investigated.It is found that most of these complexes are active for the polymerization of isoprene in the presence of[Ph3C][B(C6F5)4]and AliBu3,with the activity and selectivity being significantly dependent on central metal ions,the steric hindrance around the metal center,the spacial sterics of the auxiliary ligand and the aluminum alkyl,solvent.The dinuclear neodymium complex 4 in combination with[Ph3C][B(C6F5)4]and AliBu3 exhibited high activity and exellent cis-1,4 selectivity(up to 98.6%)for the polymerization of isoprene to produce polyisoprene with high molecular weight and narrow molecular weight distribution. |
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