Studies On Synthesis, Characterization, Catalytic Properties Of Metal Complexes Supported By New Tridentate Chelating Ligands

In this dissertation, there are three parts including the one-pot synthesis of theN,N,O tridentate titanium complexes and their catalytic behavior in ethylenepolymerization; the N,N,N tridentate titanium complexes and their catalytic behaviorin ethylene polymerization; synthesis and properties of the ONO linear trinuclearculsters constructed with bis（salicylaldimine） ligands derived from binaphthol andcobalt/nickel saltsIn chapter III, A series of tridentate anilido-imine [N,N,O] ligands2-（2-（R₂¹-2,6-C₆H₃NH）C₆H₄）HC=N（4-tBu-6-R²-C₆H₂OH）[R¹=Me, R²=tBu（LaH₂）; R¹=Et, R²=tBu （LbH₂）; R¹=iPr, R²=tBu （LcH₂）; R¹=Me, R²=Ad （LdH₂）;R¹=Et, R²=Ad （LeH₂）; R¹=iPr, R²=Ad （LfH₂）] were synthesized andcharacterized. Reaction of the free ligand LdH₂with TiCl₄in toluene at lowtemperature affords a zwitterionic complex Ld+H₂Ti-Cl₄（1d）. The zwitterioniccomplex can be dissolved in THF to form a THF solvated complex1d′. Heating1d intoluene at40°C affords a neutral complex LdHTiCl₃（2d） by losing a HCl. Complex2d can be fully converted to the final complex LdTiCl₂（3d） at140°C under vacuumby losing another HCl. Complexes3a–3c,3e, and3f were also synthesized in highyields in the same one-pot procedure. All complexes were characterized by¹H and¹³C NMR spectroscopy and the molecular structures of1d′,3b,3d, and3e weredetermined by single crystal X-ray diffraction analysis. The titanium centers incomplexes3b,3d, and3e are five-coordinated with a geometry situated betweentrigonal bipyramid and square pyramid. Upon activation with alkylaluminum andPh₃C⁺B（C₆F₅）₄-, complexes3a–3f exhibit moderate catalytic activity for ethylenepolymerization. In chapter IV, the N,N,N tridentate ligands were synthesized using the doublemethylation （1R,2R）-diaminocyclohexane as the starting material. The correspondingtitanium complexes supported by these ligans were prepared via one-pot HClelimination in high yields. All complexes were characterized by¹H and¹³C NMRspectroscopy and the molecular structures4a was determined by single crystal X-raydiffraction analysis. Upon activation with alkylaluminum and Ph₃C⁺B（C₆F₅）₄-,complexes4a-4b exhibit moderate catalytic activity for ethylene polymerization.In chapter V, Chiral bis（salicylaldimine） ligands derived from binaphthol （LH₂）were synthesized by condensation of （R/S）2,2′-dihydroxy-1,1′-binaphthyl-3,3′-dicarbaldehyde with2-anisidine. Cobalt and nickel complexes （CoL）₂（OAc）₂Co（5a） and （NiL）₂（OAc）₂Ni （5b） were synthesized via reactions of the ligand with thecorresponding metal acetate salt. Both complexes were characterized by elementalanalysis, IR, MS, and single-crystal X-ray diffraction analysis. The X-ray analysisreveals linear trinuclear for5a and5b and the metal ions in both complexes areoctahedral coordination. The two acetates separately bridge the center metal with oneof the terminal metals in M–O–C–O–M manner. The magnetic susceptibility of5abelow150K suggests the existence of a weak ferromagnetic exchange at lowtemperatures, while antiferromagnetic interactions among Co（II） cores were observedabove150K. Complex5b shows similar magnetic behavior to that of5a.