Synthesis And Characterization Of Group ? And ? Metal Complexes Supported By Aminophenolato Ligands And Their Catalytic Behavior Toward Hydrofunctionalization Reactions

Zirconium and rare earth metal complexes bearing multidentate aminophenolato ligands were synthesized.All of these zirconium and yttrium complexes were characterized by 1H and 13C NMR,and elemental analysis.Some of these complexes were characterized by single crystal X-ray diffraction analysis.Zirconium complexes were applied in the intramolecular hydroamination reaction of aminoalkenes,and intermolecular hydrophosphination of primary and secondary phosphine.Relationship between structures of catalysts and catalytic activities was evaluated.Multidentate aminophenolato ligand precursors used in this thesis are:The main findings are listed below.1.Complexes L1ZrCH2Ph)2(1),L2Zr(CH2Ph)2(2),L3Zr(CH2Ph)2(3),L4Zr(CH2Ph)2(4),LSZr(CH2Ph)2(5),L6Zr(CH2Ph)2(6),L7Zr(CH2Ph)2(7)were synthesized by the reaction of ZrBn4 with ligand precursors L1H2-L7H2 bearing different amine bridges.Complexes L8Zr(CH2Ph)3(8)and L9Zr(CH2Ph)3(9)were synthesized by the reaction of ZrBn4 with multidentate aminophenols L8H and L9H,respectively.Complexes 1-9 were confirmed by NMR spectroscopy.Complexes 1.2,6,7,8 were characterized by X-ray diffraction analysis.2.Complexes L10Sc(CH2C6H4-o-NMe2)2(10),L11Sc(CH2C6H4-o-NMe2)2(11),L8Sc(CH2C6H4-o-NMe2)2(12)were synthesized by the reaction of Sc(CH2C6H4-o-NMe2)3 with ligand precursors L8H,L10H and L11H.The reaction of Y[N(SiMe3)2]3 and L 12H gave the unexpected ionic yttrium complex 13.Complexes 10-13 were confirmed by NMR spectroscopy.Complex 13 was characterized by X-ray diffraction analysis.3.The catalytic activities of complexes 1-5 in catalyzing intramolecular hydroamination reactions have been studied and compared,which reveals the significant role that ancillary ligands play in influencing catalytic activities.Cationic species derived from zirconium dibenzyl complexes showed good activities in catalyzing intramolecular hydroamination reactions of both primary and secondary amines,and afforded respective N-heterocycles in 85%to 99%yields.Moreover,this catalytic system also catalyzed sequential cyclization of primary aminodienes,and generated bicyclic tertiaryamines in 94-99%yields.4.The catalytic activities of neutral zirconium complexes 1,3-5,8,9 and their cationic derivatives in the hydrophosphination of alkenes as well as heterocumulenes have been investigated and compared.Neutral complex 8 bearing a multidentate amino phenolato ligand exhibited high activity in hydrophosphination of simple alkenes,and anti-Markovnikov products were obtained in 37-94%yields at room temperature.Cationic species generated in situ from complex 3 stabilized by a bis(phenolato)ligand were found to be more active for hydrophosphination of heterocumulenes,i.e.,carbodiimides and isocyanates,and gave phosphaguanidines and phosphaureas in 67-93%yields.The Lewis acidity and coordination space of metal centers are modified through changes in the ligand structure,which is found to significantly influence catalytic activity.5.The catalytic activity of zirconium complexes 3-7 was tested in hydrophosphinationreaction.Complex 3 showed good activity and chemo-selectivity in catalyzing intermolecular hydrophosphination of C-C multiple bonds with primary phosphine under mild conditions.A broad range of alkenes and alkynes underwent mono-addition reaction with phenylphosphine,which generated secondary phosphines in 39-99%yields and>7:1 selectivity(over double hydrophosphination).