Synthesis Of Novel Half-sandwich Indenyl Titanium And Zirconium Complexes With Pendant Cooradinated Groups And Their Catalytic Behavior In Highly Selective Ethylene Trimerization

In order to study systematically ethylene trimerization catalytzed by half-sandwich indenyl titanium complexes with pendant coorinated groups, thirty two compounds including seventeen new organometallic complexes were synthesized. These organometallic complexes include nine indenyl titanium complexes with pendant aryl, three indenyl titanium complexes with pendant thienyl, two indenyl titanium complexes with furyl and three indenyl zirconium complexes with pendant pyridyl. All the complexes are identified by1H NMR,13C NMR and elemental analysis. The structures of C3, C5, C9, CS2, CN2are further confirmed by X-ray crystal structure which show that the pendant aryl and thienyl don’t coordinate with metal, while, the N atom in the pendent pyridyl coordinate with the metal in the solid state. All the complexes are tested for ethylene trimerization and styrene polymerization in the present of MAO.1. The results of ethylene trimerization experiments catalyzed by indenyl complexes with pendent aryl show that this series of complexes can be effective for selective ethylene trimerization, and they are more active than corresponding cyclopendienyl complexes. C3in all of these series complexes is the most suitable catalyst for ethylene trimerization;1968Kg/(molTi-h) catalytic activity and95.9%selecticity for1-hexene are abtained at the condition of0℃, Al:Ti=1000,0.8MPa ethylene pressure. The reaction temperature has a great impact on the catalytic activity and high activity can be only getted at low temperature. The structure of the complexes can also influence the catalytic activity and selectivity. Too small or too big bridge carbon group between the indenyl ring and aryl can reduce the activity. Catalyst with the substituent on the ortho position of the pendent arene group can greatly dropped the activity, while substituents on the para-position of the arene group can also reduced the activity but not too much.2. The results of ethylene trimerization experiments catalyzed by indenyl complexes with thienyl show that this series of complexes can also be effective for ethylene trimerization. Of all, CS2gives the best results;697Kg/(molTi-h) catalytic activity and95%selecticity for1-hexene can be abtained at the condition of80℃, Al:Ti=1000,0.5MPa ethylene pressure. An important catalytic feature of these series of complexes is temperature resistant. With the temperature increasing during0-80℃, the activity and selectivity is increasing graudually. The methyl on the3-position of thienyl has greatly reduced the catalytic activity, while, the suitable substituent on the5-position of the thienyl can prompt the activity.3. The results of ethylene oligomerization experiments catalyzed by indenyl complexes with furyl show that this series of complexes can not catalyzed ethylene oligomerization effectively in the condition of0-80℃, Al:Ti=1000, and under0.5MPa ethylene pressure. The activity is extremely low and the main product is polymer.4. The results of ethylene polymerization experiments catalyzed by indenyl zirconium complexes with pyridyl show that this series of complexes have no activity for ethylene polymerization and oligomerization in the condition of0-80℃and Al:Ti=1000-4000.5. The results of styrene polymerization experiments catalyzed by all above complexes show that the complexes with ary, thienyl and furyl groups can catalyze styrene polymerization. The highest activity can reach106g/(molTi-molSt-h). when using the complexes with pendant aryl goups except C6and C7, a kind of bubble-like solid was getted. This kind of solid is usually soluble in the refluxed butanone, and actually it is "syndiotactic-rich atactic polystyrene" charactered by1H and13C NMR. While, the complexes with thienyl and furyl mainly get a kind of white powder solid, most of which is insoluble in the refluxed butanone, named s-PS. The zirconium complexes with pendant pyridyl gourp however, have no activity for styrene polymerization in the same condition as indenyl titanium complexes.