Research On The Polycarboxylate Complexes And The Half-sandwich Complexes Of Rare Earth Metal Ions

As a newly-identified functional molecule-based material, metal-organic framework (MOF) has been a focus of coordination and material chemistry due to their flexible tailoring structures as well as their facile functionlizing properties. Cationic complexes of early transition metals are of great importance since they act as catalytically active species in olefin polymerization catalysis.Part1The design and synthesis of new d-f heterometallic MOFs with polycarboxylate ligands became the main purpose of this work. The optics, magnetism and ions exchange of the corresponding synthetic complexes were investigated at the same time.The thesis covers following three chapters:1. The concepts, methods, histories and new developments of metal-organic frameworks are concisely introduced. At the end of this chapter, we pointed out the importance of the search project2. Three new3d-4f heterometallic MOFs,{[Co(H2O)6]·[Ln2(ODA)6Co2]·6H2O}n [Ln=Gd (2a), Dy (2b), Er (2c)], were synthesized by hydrothennal reaction with oxydiacetic acid (H2ODA) ligand. The structural analyses showed that the three complexes all had three fold interpenetration3D anionic channels. The highly stable skeleton and guest water molecules exchange were demonstrated by thermogravimetric and powder X-ray diffraction. The properties of magnetic and ion-exchange were also investigated.3. Based on the lanthanide metalloligand, seven4d-4f heterometallic MOFs,{[Cd(H2O)6]·[Ln2(ODA)6Cd2]·mH2O}n, Ln=Gd(3a), Tb(3b). Dy(3c), Ho(3d), Er(3e), Tm(3f) and (3g), have been designed and synthesized using Oxydiacetic acid (H2ODA) ligand. The structural analyses showed that the seven complexes all had three-fold interpenetration3D anionic channels about6x6A, in which [Cd(H2O)6]2-acted as counter ions filling in it. The highly stable skeleton and guest molecules exchange were demonstrated by thermogravimetric and powder X-ray diffraction. The luminescence properties of compound (3a)(3b) and the ion-exchange properties of compound (3b) have also been investigated.Part2In this study, we have systematically investigated the synthesis of THF-free cationic rare earth metal complexes and explored their applications in olefin polymerition.The thesis covers following three chapters:1. The concepts, methods, histories and new developments of half-sandwich rare earth complexes are concisely introduced. At the end of this chapter, we pointed out the importance of the search project.2. We report the synthesis and polymerization of olefins activity of the half-sandwich scandium dialkyl complexes bearing mono-pyrrolyl and-phospholyl ligands with different substituents. The acid-base reaction of Sc(CH2C6H4NMe2-o)3with pyrrole ligands C4Me4NH or2,5-tBu2-3,4-Me2C4NH gave the corresponding scandium pyrrolyl complexes (L)Sc(CH2C6H4NMe2-o)2(L=C4Me4N,(5)),(L=2,5-tBu2-3,4-Me2C4N,(4)) in high yields. The salt metathesis reaction of ScCl3with C4Me4PK or2,5-tBu2-3,4-Me2C4PK afforded the scandium phospholyl complexes (L)Sc(CH2C6H4NMe2-o)2(L=C4Me4P,(6)),(L=2,5-tBu2-3,4-Me2C4P,(7)) in high yields. The substituents on the ligands and the difference of the hetero atoms showed great influence on the activity of styrene polymerization, copolymerization of ethylene with norbomene, copolymerization of1-hexene with norbomene, and copolymerization of1-hexene with dicyclopentadiene, isoprene polymerization in the presence of a half-sandwich rare earth complex in combination with [Ph3C][B(C6F5)4].3. we report the reaction of dialkyl complexes2,5-/Bu2-3,4-Me2C4N1.n(CH2C6H4NMe2-o)2(CpN=2,5-tBu2-3,4-Me2C4N; Ln=Y(6a), Er(6b), Tm(6c)) with AlMe3to afford the trinuclear rare earth methylidene polymethyl complexes [CpN3Ln3(μ2-Me)3(μ3-Me)(μ3-CH2)](Ln=Y(6e), Er(6f), Tm(6g)) in which each Ln atom is surrounded by one CpN, two μ2-Me, one μ3-Me, and one μ3-methylidene groups, forming a distorted trigonal-bipyramidal geometry. Moreover, the methylidene polymethyl complexes reacted with ketones to give methylenated products via formation of C-C bond and cleavage of the double C-H bonds of the phenyl groups.