| Abstract: In the present paper,we are reporting the novel tetramethylene-bridged titanocene and zirconocene dichloride. Tetramethylene dicyclopentadienide disodium reacted with tetrachloride titanium and zirconium separately at room temperature in tetrahydrofuran to prepare tetramethylene-bridged titanocene,(CH2)4(C5H4)2TiCl2 yield 21.4%,m.p.104-106℃.δH:6.37,6.24(8H,m,2C5H4),2.74(4H,t,2α-CH2-),1.19(4H,m,2β-CH2-) and tetramethylene-bridged zirconocene dichloride,(CH2)4(C5H4)2ZrCl2,yield 24.5%,m.p.77-79℃.δH: 6.27,6.23(8H,m,2C5H4),2.68(4H,t,2α-CH2-),1.19(4H,m,2β-CH2-).In the methylene-bridged titanocene dichlorides,(CH2)n(C5H4)2TiCl2(n= 1,2,3,4),since the C(1)-C(1') distance for two aromatic cyclopentadienyl ring increases as the number for methylene-bridged increases and a shift of π-electron density away from the bridgehead towar to distal ring position,the Ha chemical shifts move to lower-field,and Hb chemical shifts move to high-field according to the order of decreasing of number for methylene-bridged. The proton chemical shifts for tetramethylene-bridged titanocene dichloride and bis(ethylcyclopentadicnyl) titanium dichloride are similar. The results show that the molecular structure of tetramethylene-bridged titanocene dichloride bears analogy to bis(ethylcyclopentadienyl)-titanium dichloride. |
