Effects of an Interannular Bridge on Spectral and Electronic Properties of Bis(cyclopentadienyl)- and Bis(indenyl)zirconium(IV) Complexes

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• 作者：Ulrich Wieser ; Frank Schaper ; Hans-Herbert Brintzinger ; Nora I. M&auml ; kel&auml ; Hilkka R. Knuuttila ; and Markku Leskel&auml
• 刊名：Organometallics
• 出版年：2002
• 出版时间：February 4, 2002
• 年：2002
• 卷：21
• 期：3
• 页码：541 - 545
• 全文大小：162K
• 年卷期：v.21,no.3(February 4, 2002)
• ISSN：1520-6041

文摘

Interconnection of the indenyl ligands of bis(indenyl)zirconium dichloride complexes by a1,1'-positioned Me₂Si or (CH₂)₂ bridge causes pronounced bathochromic shifts of the longestwavelength UV/vis absorption bands by ca. 50 nm, while much smaller shifts are caused bya Me₂Si bridge in otherwise analogous bis(cyclopentadienyl) complexes. Extended HückelMO calculations show that overlap between the empty 4d orbitals of the ZrCl₂²⁺ fragmentand the highest filled mages/gifchars/pi.gif" BORDER=0 > orbitals of the indenyl anions is decreased when a Me₂Si bridgeforces the indenyl ligands into a lateral orientation. Consequences of this orbital mismatch,e.g. on electron densities at the Zr center, are discussed.