A Valence Bond Analysis of Olefin Polymerization Catalysts

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A Valence Bond Analysis of Olefin Polymerization
Catalysts
Timothy K. Firman and Tom Ziegler
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p-Conjugated Ligands in d0 Systems
X groups are isolobally analogous
Several good catalysts of this type are known
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Resonance Structures
A localized bonding picture of these
ligands requires multiple resonance structures,
e.g.
Main group elements require an octet of
electrons Bond order to metal is variable, which
may facilitate bond breaking during olefin
insertion
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Model Compounds
X CH2, SiH2, NH, PH, O, S